Does anyone have any experience/own a .458 WSM?
Load data would be appreciated for my new build.

You might check with Kevin Weaver (Weaverrifles.com)
He's been making WSM's in .375 and others for a while now and seems to know a lot about it.
He is just east of you in Falcon.

Max

There is a fellow, Chris I think something or other in Australia that did what he calls a 458 Alpine. His purpose was for some sort of mean ass deer. The rifle he built has a very long barrel, like 26 inches or something such. It's a 458 WSM is all. With it's longer barrel it is about equal to the 458 B&M with the 18 inch barrel. However some of the loads he is publishing I am sure is some over max. It can be found on ammoguide I think.

Michael

Noveske posted about his experiences on here several years ago.

As I recall he called it the 458 Noveske and Hornady's Custom Shop made the dies for him.

Found it:

http://forums.accuratereloadin...=291108601#291108601

Thanks guys!
Appreciate the info. I'd read about the Noveske on this forum and several others.

Snellstrom: Had never heard about Kevin Weaver before. I will get in touch with him.

Michael 458: Had heard about the .458 WSM and think it might work well in that BLR I've been talking about. Got a Browning parts supplier/gunsmith who is willing to give it a shot and thinks it will work well. We'll see.
Max

Max

Yes, that might work, maybe short enough to go through the magazine without much change to it. Just might be the ticket.

Michael

The 458 WSM has been around for a while and a search for "458 WSM" will turn up a lot of good information. There used to be a WSM website but it went away several years ago, but you might still find something still remaining online.

There is also the 458 Alpine and the 450 Yukon(done for a V threaded Marlin 1895) you might look up. Checkout CH4D for all the various already available iterations he has dies for.

I have a 450 M BLR and was thinking along the same lines...and also a 500-510 WSM possibly, but getting the barrel off is the problem....If I could have found a safe way I would have one already.

The 450 M clip without the spacer block will handle up to 2.95" COAL and I tried some WSM dummbies to see how they would work...OK except only 2 down and the feed lips would need some tweaking.

I think a take-down BLR could be converted as then it would only be a rechamber job basically and tweaking the mag, but if you have the "solid" barrel/receiver all the Browning people I talked to wouldn't touch it because of needing special tools to keep from tweaking the aluminum frame for certain and a question about doing the same with the steel framed older rifles because the barrel is screwed on so tight...just like ALL Brownings.

I also emailed the factory and they declined my "offer"...They will replace with a barreled receiver only in any caliber that they chambered for and use your old internal parts, but not just the barrel itself...

I haven't heard anything about just swapping take-down barrels around, but that would be a possible option....an easy rechamber of a 450 Marlin barrel. I keep looking for a take down BLR to measure, but haven't come across any in my area.

There seems to be a small amount of chatter about "wildcatting" the BLR's and I keep searching for a way to wildcat my solid BLR.

All the strength is in the barrel shank and the receiver is just a place to hang the scope on as another poster put it.

The way the BlR/BARs handle the bolt lockup and timing makes any kind of wildcatting a bit difficult and not for the faint of heart.

I also inquired about doing a 458 WM on a long action BLR/BAR and ran into the same problem of no one wanting to touch the receiver because it is so thin and REALLY stuck together.

Hope you have better luck and let us know what you come up with.

Luck

Foobar,
You have summarized almost all the info that I have come up with. On a BLR takedown in .450 Marlin, it is easier to rechamber the barrel to .458 WSM than rebarreling. Rechambering would have to be done by hand due to the piece that the barrel screws into and bolt locks into.

One thing additional on the magazine, the BLR's WSM magazine will hold three down, but require more tweaking of the magazine feed lips. Had a comment on the scope hanging on the aluminum receiver and found out that Browing has a steel plate under the top of the receiver to ensure the scope will hang on.

Foobar, have you uploaded the .450 Marlin at all considering the cartridge is loaded to 42,000psi and the BLR is good for well over 62,000psi? Any data on this?
Max

I have loaded my 450 M with 350 gr to 550 gr jacketed and cast bullets well over 450 M SAAMI specs, near 60KPSI as far as I can calculate, but NO guarantees WHAT pressure was actually produced. The BLR is a strong rifle and none of the loads I worked up showed an sign of being squirrely or going close to the dangerour pressure zone.

I used AA2230, 2460(5% slower than 2230) and 2495, Varget, H4895, 748 a few times and BLC-2, IMR 4198, RL-7 and RL-10(in 4 different 45 cal rifles with close case capacities) and I have some 8208 and Benchrest I want to try but haven't found the right toit yet.

I don't post my actual loads for safety reasons and because I don't have a way to measure the pressures directly...I run Load from a Disk and Powley online software to get a general idea but don't push anything as software programs are just mathamatical constructs and the results can vary widely.

You can also get a good fit if you just do a little extrapolation and iterpolation with the data posted in the powder web sites as most of the IMR/H log type powders are linear as to pressure/velocity curves and don't usually do any strange pressure excursions...

Even though you have a fairly wide pressure window to work with, the cases are about 20% apart so a small increase in powder amount will cause a large increase in pressure but not necessarily a large increase in velocity in the smaller case.

It's one of those "is it worth the small increase in velocity" things.

If you have a BLR smart gunsmith who can take out the bolt and then time it correctly when putting it back together, and can keep the headspace correct(you only have one chance to get it right) you can do either a "through the receiver" or a "through the barrel, pull" rechamber to either a WSM case or use a WM reamer or throater to lengthen the chamber, then pick whatever case length you want...in effect using the case mouth as the headspacer.

BUT...The FLY IN THE PIE...The WSM case gain depends on the case design you use and you have to open up the bolt face to handle the larger rim OD on the BLR which micht weaken it a bit....maybe not enough gain to go through all that trouble unless you go to something like the 458 B&M which is a shortened RUM case which would put you in the 458 WM volume range...90 plus gr H2O...NOW you're talking GAIN.

Get a subscription to AmmoGuide if you don't already have one...lots of good information on WSM iterations there.

I measured my 450 throat length at 2.15" then trimmed some 458 WM cases to that length, did a bit of milling on the mag block stop to get a COAL of 2.65"...take that block out completely and you can go to 2.90" and have room to spare. I loaded up some 500 gr cast and worked up beyond 1650fs with no pressure signs, EZY extraction, no primer flattening and no leading...cast bullets are not hard on the pressure end.

I load Hornady 350 gr FP's at 2.65" COAL loaded over 450M SAAMI specs in the rifle, 435gr TruShot cast same COAL in the 2rd mag, and 500gr RN's in the 3rd mag...quick and easy to swap around...but I worked up slowly and stopped somewhere near the 60KPSI point.

I have a 45-120, a BLR 450 M and two 458 Americans...a Marlin 336 - 2.65" COAL max and SMLE - 3.05" COAL max. The BLR 450 M is the most reliable feeding of the lever/bolt guns so I'm not going to muck about with it although the SMLE is a very close second...the Marlin, well, it's a levergun and works OK until it gets tipped over one side or the other too far.

I run ~2200fs with 425-450 cast bullets in the SMLE with AA2460 42-45KCUP somewhere near 53-55KPSI, but at a 3.050" COL so let YOUR safety be your guide with the BLR.

I keep looking for a used 450 M take-down, but to do a shortened 2.3-2.4" 458 WM or RUM case, which will give me a ~85-95 gr H2O capacity case and a much higher gain in velo which translates into much higher energy.

Anytime you do a wildcat you walk on the wildside...literally...and there are many considerations to look at before you jump...but you might have already done you homework.

Luck

Foobar,
Thank you for the info on your loading. I understand not wanting to publish specific data.

According to one gunsmith, the bolt head may not have to be changed to a WSM factory one, or altered. Some boltfaces for the .450 Marlin cartridge are actually .534 and some WSM brass have a head dimension of .533. That might make this a better proposition. In any case, it would be only a .002 to .003 increase, if needed.

Yes, with the takedown model. a simple through the rear of the barrel rechambering is possible. the .555 body of the WSM will clean up the chamber just fine.

The idea of the .458 B&M was suggested to SSK gunsmithing. They looked at a BLR in .450 and did not recommend it due to case length and magazine used for feed ramp. The WSM case looked like the best idea. The .458 WSM is listed as having an H2O capacity of 85+ grains. That should bring it close enough to the .458WinMag for me. I think that may be enough recoil for me to manage in the BLR.

I appreciate all the help and suggestions you have provided. Yep, done a lot of homework on my own, but learned long ago, someone may know something that I may have forgotten or never knew. Keep an open mind.
Max

I measured my bolt head at ~0.545" and a WW 270 WSM at a slightly oval 0.533" - 0.535" and the case would seat down into the boltface recess all the way to the bottom and the extractor would catch and eject the round.

I just wasn't thinking...the BLR is chambered for several WSM cartridges now, so I would suspect most if not all the later BLRs have only one bolt head since the WSM case came out.

I've seen case capacities running from ~82 to ~90 gr...as I said it all depends on the OD of the shoulder which runs from ~0.538" to ~0.545", and whether the shoulder has been moved forwar and shortened and/or the shoulder angle...lots of play going on in those areas.

Bob Wilson, originator of the 450 Yukon, used a 300 RUM case shortened and resized as it was easier for him to size down that size up. The shoulder was left a 0.536" and basically standard WSM other dimensions... 2.1" OAL, 0.360" neck length.

Check him out, he posted some load data...the recoil level is what stops most people with large calibers in lighter rifles...my BLR is lighter by about 24 oz than my Marlin and does give a right smart slap, but it seems to be more backwards than upwards and I have a MB on the Marlin 458 A barrel which helps a bit.

Not sure why the mag wouldn't work with the B&M case without the block...when I had the block out on one mag to modify it to get a longer COL, I tried several case lengths out to ~2.45" and out to 2.75" COL without any problems...

You might have to include some kind of block/ramp at the end of the mag maybe for that cartridge just to get the bullet nose up a little, but I didn't fiddle with it over 2.65" COL, but maybe the difference in case OD opens up problems that I didn't look into.

Every wildcat I ever worked with/on in every rifle has it's own problems to solve...that's what makes wildcatting so interesting.

Luck

Here is the twist
Literally
The twist of the barrel is 1 in 20"
That means 400 and under grain bullets for optimal terminal performance.
The case capacity is better suited to 400 grains anyway so how about a rebore of a stock WSM to say a 400 WSM to get 405 win to 450/400 performance.
On a 450 Marlin conversion a 458-300 RCM might be worth doing first and have potentially no issue using the 450 Marlin mags. Just my twist on it

Those are excellent ideas, Boomy, the only problem is with the BLR/BAR barrel being screwed into a the part that the bolt locking lugs fit into and THAT part press fit into the aluminum frame...getting those pieces apart without ripping something apart is the main issue. I can't find ANYONE who will attempt it and the factory doesn't even to it...it replaces the whole receiver/barrel as one unit.

In the older steel framed rifles, one 'smith I talked to said it can be done but no guarantee that the receiver OR the barrel will survive...Browning runs those barrels into that boss so tight there is a good chance of gauling or stripping threads.

If a 400 cal barrel were available for the BLR/BAR that could be rechambered then your idea would work...that platform is such a perfect platform to do lots of neat things except for the barrel/bolt lockup problem., but I still keep digging to find a solution.

I've looked at the RCM case hard and there are conversions using that case in Marlin 1895 V threaded action on one of the Leverguns sites that addresses the weakness in the Marlin receiver.

I think Browning would have a winner if it came out with a 405 Win or a 400/416 WSM...lots of folks would like them I think...I definitely would find a way to buy any of those.

Luck

Foobar,
You got it on the bolt head measurement. I think though, that the RUM casehead measurement is a little larger. Will find some cases and measure that.

Having the shoulder out to 0.540 - 0.545 would seem to ensure an adequate gain in case capacity. Moving the shoulder forward would be an excellent idea, but then the magazine conundrum comes up. If that weren't the fly in the ointment, I'd have a .458 B&M built up! Your comment on making a block/ramp in the front of the mag. Any ideas as to shape and how to do it? Might be willing to give up a little COL for better feeding.

Emailed Bob Wilson, but have not received a reply as yet. Am hoping. I did read everything he'd written on the Shooter's Forum pertaining to the .458 Yukon cartridge.

Boomie,
I would love to have a 1-12 or 1-10 twist barrel, but as has been said above, rebarreling is not an option. 400gr and under .458 bullets is not that great a restriction.
Reboring say a .325WSM is a possibility to .400, but nothing larger. I want .458!

If 45-70 bullets are the bullets to be used then maybe a 2.4" win mag case and 45-70 bullets. Add some spacer so you can use any normal belted case. Use a 458 win mag reamer to 2.4" maybe and 458 win mag dies. Think of it as a belted 45-90

The 300 RUM cases that I have measure the same as the 270 WSM...the RUM is just longer.

Take a look at the 458 Alpine on AmmoGuide...get a subscription if you don't have one...it is the best deal for 20 bucks I've come across for a long time.

The Alpine, WSM case, has a shorter neck at 0.295", shoulder moved forward just a bit and altered to 40° and shoulder blown out to 0.545"...87 gr H20, 2.1" case length.

Basically what I would do if I was going to use the "fat" case, but I would use a RUM case and move all the measurements out an additional 0.100 - 0.200" so I could match a specific bullet cannelure and max COL for the BLR mag.

I like the 430 gr TrueShot "Silver Bullet" as the Trueshot bullets are the most uniform cast lead bullets I've come across...almost as uniform as jacketed. I ran a lot of bullet weight/velocity numbers through Load from a Disk and the 425-450 gr slugs gave the the highest velocity/energy/SD/BC numbers overall with the 450 M/458 A case size. 350gr was faster and in some cases gave higher energy but the SD and BC of the heavier 425+ gr had better SD and BC's so the might penetrate and hold their velo better...alwasy highly argumentive...depends on the game, a 45 cal bullet will do all the damage usually required. Probably try a WSM magazine also.

Each additional 0.100" with a 0.545" shoulder OD will get you an additional 5 gr of case volume.

As to the block, that would basically be a cut and try thing, taking the height measurement from the block and basically moving it toward the front of the mag on the new block. I took 0.065" off the block, I think, (can't recall exactly right now and I posted that data somewhere also) on the one mag...just milled it down to just before cutting into the two roll pin holes.

To gain more mag length those pins need to be removed altogether and the block fitted then epoxied in or pinned from the front or bottom...I haven't really taken a good look...the block is simple to make.

I posted somewhere here on how I used/did the 458 WM belted mag case thing in the 450 M along with the actual difference in belts...it isn't a lot and as long as you watch what you're doing when matching all the different components, i.e., chamber length, case length resizing, case mouth expansion and taper crimping and load adjustment, it is safe to do...just do a search for NFG and it should turn up...I also posted some of the information on the SMLE 458 American I did also...I used a 458 reamer and adjusted the case length to fit the different bullet cannelures to get the COL of 3.050" for the SMLE OEM 308 mag.

Don't forget that there are lots of things you could do to the 458 B&M case and COL to get the extra case capacity and fit the mag...seating the bullet down a little deaper, trimming the case down, using a shorter bullet with a larger diameter meplat. You don't have to go lockstep with what SAAMI says. Boomy is right...case capacities for the 2.4" belted mag and the 45-90 are almost identical for all intents and purposes as far as hunting is concerned.

You could also have the 458 Alpine reamer ground with an additional 0.100" or a little more and use trimmed down RUM cases and be slightly shorter than the B&M and gain the additional shoulder angle and larger shoulder OD. The reamer and dies have to be custom made anyway so why not do a little more customizing?

Wildcatting is all about learning how to skin a rat 17 different ways for each day of the week.

Luck

I calculated that the 2.4" 458 win mag case would have 90 grains an that is exactly what the 45-90 case is. That is more capacity than the WSM and if only using 45-70 bullets it makes more sense and would be easier conversion on the 450 Marlin BLR. Use 45-90 loads with 45-70 bullets for light loads and quick load what could be done at 60k PSI
The belted 45-90 could be an all off the shelf wildcat conversion and that saves time and money.

Thn 2.425" R-P cases I use in my SMLE run 88 gr H20 +/- a grain or so actual water weight, 2.35" run ~85 gr., 2.3" ~83 gr.

WW cases gave slightly higher weights by a couple gr...actual weights depends on the brand anyhow so it just takes mucking about with a few to find the max average amount of H20 between the brands. I'm guessing Norma and Lapua might give slightly lighter amounts.

Using an extended 458 Alpine configuration, extending all the lengths by 0.200", 2.3" OAL, neck length 0.295", shoulder 1.968, the H20 capacity is increased to ~98 gr H2O and with a TrueShot 430 gr bullet seated to the crimp groove ends up ~2.78" which seems fairly easy to achieve in the BLR mag with a slight additional milling of the block...and shouldn't pose a major problem in feeding.

The B&M has slightly different measurements and a smaller OD shoulder which accounts for the different water weights.

Using a 458 WM case trimmed to 2.3" would do the same but end up at ~83 gr H20...a longer case wouldn't increase the NET capacity unless the seating depth was increased which is a bit iffy in this application...and DEFINITELY would be the cheaper and easier way to go...one of the reasons I went with the 458 WM in my SMLE instead of going a WSM, Rigby, or Gibbs cases I also played with...higher cost of reloading dies...my Rigby cased 510 Makatak dies ran $275.00 with an extra seating stem...seems a bit dum-bass when comparing to the cost of standard 458 WM dies.

This is boiling down to case volume as the COL at 2.75- 2.85" is about maximum for the BLR short action. All the other normal alternatives of rebarreling/reboring having been eliminated.

If you REALLY want to go all out, using a Rigby case is another alternative by the expedient of rebating the rim to fit the bolt face...2.3, COL 2.80" with similar dimensions as the "extended" Alpine would net you ~115 gr H20.

I trimmed a rigby cast to 2.350" and it fits the mag but the follower would need a bit of taper matching and looks like it will only hold 2 down, but 115 gr H20 would give you TONS of whack and put you into the 450 Watts/Ackley room in a short case for certain...and add a bit more complications.

I gotta quit this...I'm starting to think about swapping my 450 M "solid" for a take down...Jeezzz...I need this like I need another "wife from HE**.

Luck

I was thinking about the COAL when I came up with the 2.4" case length and 45-70 bullets. I agree that cheap, fast and easy is a good starting point. The case could be trimmed back depending on bullet type. My guess is that 400 grain barnes busters at 2,150 coul be easily achieved and would be pretty potent on anything under the big 3.

Yeah...that bullet would be excellent...I wouldn't feel slighted using it. NF and Hawk have some nice FP's that would fit the bill also.

This is what the Rigby 2.35" case looks like in the BLR mag.

The case mouth is 0.570" now and it hangs up on a bunch of protusions so this would need a takedown model to even begin the fiddling, and none of my belted mag cases will accept the case to begin any kind of necking down.

I might fiddle with making a tapered "neck squeezer" to get it down far enough to run into a 458 WM die, then do a 0.300" neck length and stuff a boolit in it just to see if that will solve the front end issues...the only way to solve the bolt face difference is to open it up to about 0.600"...the Norma brass rims measure 0.585".

You never know...I might end up with a 450 MAKATAK S&F(short and fat) on the Rigby case. Probably a Mr. Allready Bendone.

I have some extra time now that the 6mm-284 barrel is on it's way back to it's maker...that or go fishing.

Luck

Boomie: You mentioned a spacer. How would this work within the chamber to shorten the area needed for the belt?

Foobar: Your idea of the Alpine case is excellent. I am not necessarily trying to equal the .458 Win Mag. All I want to do is use Mike458's bullets and take a cape buffalo and maybe a hippo. Elephant is not on the menu for me...yet. I'm thinking 85-90 grains H2O capacity would be sufficient. Comments?

Handloading cast bullets at heavy .45/70 velocities is definitely in the plan for hogs. Bullets from 350-425gr would be the standard.

Yes, the RUM case is what I plan on using...unless Boomie's idea of lengthening the chamber with a .458 reamer make more sense in the long run.

Looking at the block at the front of your magazine, it seems to me that removing it, milling the front of it and reshaping to fit the magazine would definitely add to COL and still ensure good feeding. More could be added by a slight milling of the rear side, being careful to ensure the feeding ramp is still effective. Epoxying the block back in would then definitely be needed, as you said, and eliminating the pins altogether.

The Rigby case is not one I'd choose to go to. Cost of cases, dies, etc., climb really fast as I've learned with several other wildcats. If a reamer and dies have already been made and used, it becomes cheaper for an additional set to be made.

Current thought is to try the extended chamber with .458 WM cases. Limiting length to no more than that used with the WSM. Trying that. Then if more is wanted, go to either the Alpine improved chamber, or all out with a B&M chamber.

Sounds like a plan to me.

What you are looking for is NET case capacity after bullet is seated to the desired COAL...the column of powder is what makes the world go around.

I don't know the bullet OAL of the bullet you want to use, so the NET data I'm posting is from a bullet in my data bank...at a COL of 2.75"...doesn't matter whether you use a 458WM or 450M case, the powder column will have the same length and net volume...~56 gr H20, with a 430 Trueshot about 1.100" long.

For a case diameter of about 0.480", for every 0.100" you gain/loose about 4.5 gr H20 so you can measure Mikes bullets and compare his length to the 430 TS length and do the math and come up with the net for those belted cases. His bullets are solid so they will be longer for equal weights and using a lighter solid bullet will get you the same effective result as using a heavier lead/copper bullet...at least that's what seems to be the case.

As far as the Aline is concerned, for the same 2.75 COL the NET volume is ~71 gr H20.

You don't have to load it any more than is comfortable for you...maybe half way between 450 M and 458 WM...or ??

A couple more pics...this time with a bullet at 2.75" COL...forget it's a Rigby case, it shows where the bullet ends in relation to the block. From this perspective I would mill off the front of the block then mill the edge angles...would be simpler and quicker than doing it from the back. You might also need to add an extension to the front of the follower so it wouldn't move around...having the follower deside to go to Florida at the wrong time could cause some discomfort, usually at the wrong time.

If you decide to go the belted mag route, from my perspective I wouldn't mess around with spacers unless you intend to glue them on...the difference between a 458 WM belt length and a 450 M belt length is about 0.025"...trying to make a 0.025" wide by 0.530 OD shim/spacer with a 0.513" hole in it is more than what I want to contemplate, even it you just use 0.025" brass shim stock and try to shave off a 0.025" sliver to bend around, cut and attach is way more than I want to attempt...it can be done with the right equipment but I think the cost in time alone would make doing a Rigby dance seem like chumpchange.

All you have to do is fit the case length minus 0.005" or so to where the chamber mouth ends and use a taper crimper...basically it will be the same thing Mike is doing with his cartridge line...headspacing on the mouth of the case and using the action of a tapered cylinder inside another tapered cylinder...no muss, no fuss...been working in lots of cases for millions of years, or maybe millions of cases for lots of years.






From what I understand of your interest/desire I would go with the ALPINE and call it good...basically a rechamber, dies and load development at the optimum all around lever...but it's GONNA SLAP YOU GOOD, I garoantee...and you will have a very high bragging level to boot. Hahahahahahah

Luck

Regarding the 25 thou spacer
One guy said epoxy lol.
I would post a query in the gunsmithing forum.
I personally would want the a steel washer press fit in.
Nominal 45-70 tip to crimp is length is .45"
2.4" case + .45" = 2.85"
If using longer bullets just trim back.
If going back below a 2.3" case you might as well just load long from the 450 Marlin and lengthen the throat.
If going a fatter case I would do the 458 B&M SA. Thats michaels 2" version of the B&M. Use longer rifle bullets and load out 45-70 bullets.
If a 2.85" COAL 458 win mag case feeds then that would be my sows ear purse.

Yep, the thing is gonna SLAP me, although some friends consider me "punch-drunk" already from some of the calibers I do shoot.

Boomie: Do you know offhand what Michael's .458 SA's case capacity is? That might solve all problems at once.

Now, a little mush. I do really want to thank you two for the assistance in this project. We might be called the Cerberus, you know, the three-headed dog from mythology?
Max

Yeah, Boomy, EPOXY...the hight temp stuff. Of couse, the comment was more tongue in cheek than for actual use...I was illustrating the problems with trying to use/make a 0.025" wide by ~0.012" "spacer" that isn't required in the first place...the conversion to belted mag case data is posted already just for a little bit of searching and looking closely at one of my posts on this thread.

Not sure about the .45" crimp length thing...I have 45 cal bullets with crimp groves anywhere from about 0.375" to about 0.750". Where the crimp groove ends up depends on many things...besides you can always crimp in a grease groove or forget the crimp altogether and use a taper crimper.

I don't worry about crimp grooves per se, there are many ways around crimping that will work well...I hardly ever think about the grooves unless they just happen to fall at the right place for the COAL I want to use...and it is simple just to trim slightly if needed.

The other part of this is flexibility...picking a COAL to fit all the parameters as closely as possible...i.e., bullet weight, construction and material, crimp groove if you want to use it and bullet length, chamber length, throat length...then match the case length "made to order" so to speak.

No way will you gain anything as far as NET capacity, velocity, etc., by using the 458 WM case over the 450 M except you DO gain case length for bullet grip, but the effectiveness of that is up for grabs as using a 450 M case will still get you 0.350" to 0.450" grip on the 430 gr TS, 1.100" long, depending on the COAL from 2.75" to 2.85".

I like at least 0.400" of bullet being gripped by the case and using at least 0.004" of expander grip by polishing the expander button especially on hard recoiling, heavy bullet, large cal rounds.

That might be a moot point considering the Alpin has a 0.295" neck. Another reason for using the RUM case to form the Alpine is to get a longer neck grip.

There is always more than meets the eye when contemplating ANY wildcat conversion and you have to understand and consider all the aspects from all the angles.

Even after I complete a wildcat project and have the rifle and ammo in my hot, sweaty hands I see things I could/should have done maybe a little better or at least differently, but second guessing and Monday morning quarterbacking soon goes away...usually at the recoil of the first shot.

I pick a specific receiver length, caliber and bullet, then design a case around it. I want the highest NET volume I can get within reasonable expectations, going from a .473 case to belted mag to WSM to Rigby to Gibbs as the case may be...which usually means a "blown out case" with minimum taper, case length as long as possible, COAL to fit the mag, shoulder positioned to achieve the length and level of grip for the expected recoil, shoulder angle to achieve a good feed and efficiency...and so forth.

That level of expectation is why I would go for the "extended" Alpine rather than the "standard" Alpine if I were doing this project. The reamer and dies will cost the same.

I won't do a 450 Alpine BLR, ecomonically and reality wise that's beyond question, but I could do a rechamber on the 458 A SMLE or a swap barrel for My Ruger Tang 510 Makatak,...the shorter WSM or Rigby case will work much better as far as COAL is concerned and I don't think the sage rats fill feel the difference...Jezzz...here I go again.

You can gain ~12-14 gr H2O more volume by just long throating the 450 M and fiddling the mag, then seating to 2.85"...~9-10 gr by seating to 2.75"...that's about what most Ackley Improved versions achieve and will gain ~25% of those amounts, percentage wise, in extra velocity...12 gr x .25 = 3% more velo...~2.5% with 10gr...

PLUS the extra velo by loading to the higher pressure limits...roughly 100 fs more with a 400 gr bullet just by long throating and seating out...1900fs to 2000fs, roughly 275 more ftlbs of energy...a very cheap and effective way to get more pizzazz...

But by going to the WSM, WHICHEVER one you pick, you can have that same increase in velo/energy, but with the additional reserve capabilityies of going to 2200fs and WELL beyond...just like having a 500ci engine in your truck...the performance is there if and when you want it, otherwise you just pay a little more in gas over a 350ci.

If you're not looking for a "short, fat" 458 WM then just long throating the 450 and seating out will get you a very LONG leg up without much extra cost...just the cost of a long throat job and some mag work...and you can use the 450 M dies. TOTALLY CHEAP.

The problem with Cerberus is he had his head in our world and his butt in the nether world, and came out of a really UGLY mother.... hahahahahahahaha

Luck

You can go in stages
First start with a long throat.
That is cheapest way to make a bigger boom
Call it the 450 Marlin Nitro Express
If that does not float your boat try the longer case.
If that bores you go 458 BMSA
if that does not blow your hair back go for the 458 WSM
I've always wanted to be 1/3 mythical creature lol.
Maybe start from scratch and name it the 458 Cereberus
Since the chamber is already 2.1" might as well have a case that is 2.1" long I guess. I say rent a 458 throater and call it the 458 Mad Max

Hey...that would work...cool name...lots of ways to get "somethin' somthin'". A 45 cal "Whatever" makes acquiring nice, thick BBQ'd steaks...EZY.

Looking forward to what "IT" actually ends up.

Luck

More good info on increasing power.
I had pretty much came to the same conclusion as Boomie, to try modifications in stages. The longer case might be skipped, or the .458 BMSA. I think the .458 WSM will be the final change.

As far as names, I like the .458 Cerberus better than the Mad Max. Already got my name on the .395 Max by Ron's insistence.

Hey Prof242...call Wild Wild West Guns...they can do your conversion if you supply the reamer...REF: Leverguns, this forum.

I'm working up a dimension drawing for a reamer from PT&G...the 450 MAKATAK..."stretched Alpine", 2.3" case, COAL 2.75" - 2.85", case volume ~112 gr H20...a "short action Lott" using trimmed RUM cases.

Of course if I REAllY went nutz I would use the Rigby case and end up with a short action Lott.

This is basically just a rechamber so maybe I won't have to hock my soul to get it.

Luck

2 cents
I like the idea of a 2.25" Rigby case better.
To get the Lott case capacity might need to go 3.35" on the blown out short neck rum case.

I did a Rigby case design, 2.3" case length, 0.575" shoulder, same shoulder angle, neck length, etc., 2.75" - 2.85" COL and came up with ~112 gr H20 plus or minus a bit depending on case wall thickness...That was the case in the picture of the BLR mag.

The die cost will be HIGH...for the RUM based case from CH4D they run about $175- 185 including shipping...going to the Ribgby case adds another $25 or so.

I agree it would be a very nice proposition.

Depends on how much you want the product, how much you are willing to pay to get it and how deep your pockets are.

When I hit the Lotto I will have a few made...BLR AND BAR...take-downs for sure....Hahahahahahahah

Luck

quote:

Hey Prof242...call Wild Wild West Guns...they can do your conversion if you supply the reamer...REF: Leverguns, this forum.

Whatever you do---DON"T CALL WILD WEST IDIOTS! I had them do a 50 Alaskan for me some years ago, and it was the most awful mess I had ever seen. You could not feed a 50 Alaskan into the magazine tube, the rifle would not CHAMBER a 50 Alaskan case, nor cartridge. They took 8 months longer than THEY SAID to begin with, they were paid in full to begin with. In the end, they could not ship the rifle for over a month because they did not have a BOX to ship it in! No, don't call wild west morons for anything! I sent it to Brian, he sorted it out. I got rid of the POS as well! I would not have it in my lab with their name on it! End of Story!

Anything else you decide Max, I am happy to help any way I can!

Michael

That's good to know...you're the second person that thinks WWW isn't worth cold ****.....One person getting dinged is questionable...You have a proven track record, Michael, and excellent products so...???...I've read several acounts of people with WWW conversions that rave over their shooters.

I can't believe they couldn't find a shipping box...what kind of hokey BS is that??? That kind of excuse, phoney BS alone makes me think there's something smelly going down in Alaska.

I was going to email them with my specs for a price quote for a rechamber only and more detailed info plus some pictures of their shop before I did anything.

I have talked to another smith that will do a steel framed BLR or BAR but I need a lot more information on HOW WWW handles an aluminum framed, solid BLR before I will let ANY gunsmith touch one of my shooters...I've been burned twice and that's one to many.

My simple solution is to sell/swap my solid frame for a take down and do the rechamber myself. Probably could do it through the receiver, just need to setup an extension to hold the reamer. I think I will dig around to see if I might have and extension somewhere hide out I forgot about...Senior dementia can really mess with a guy...

There might be enough meat in the barrel to rebore to 0.500 or 0.510 for your 50 B&M Long...0.730" OD...0.0115" muzzle walls...or maybe a .475 cal.

Luck

Guys,
My Browning BLR in .450 Marlin is on order!

Upon arrival, my work begins. I agree with Michael about WWW. Have heard a number of complaints from different people about their service.

I probably will have to order my own reamer and have my local gunsmith do a rechamber after the tests with the .450 Marlin and lengthening the chamber with a .458WM reamer.

FOOBAR: Your .450 MAKATAK sounds like more than I think I want...although? As I said, I think what I want is 90gr case volume, maybe a little more. 100gr might give me some leeway and allow lower pressures.

I've been advised to go to a steel frame also, but the takedown model just is so, so, so... Okay, techie. Your idea on a rebore was a thought to me, also, but not sure if there is enough meat in the barrel for a .475 cal.
Max

Good idea with the 458 win mag reamer.
Will you just use it for the throat or go to 2.4"?

I used a 458 WM reamer to do both of my 458 A's.

Using it did two things at once...lengthened bullet end of the chamber and also lengthened the throat. I used a 45-120 reamer, then a 45 cal throater to lengthen the chamber on my NEF BC to get the almost 5" length required to use 720 Gr bullets.

If you're going to stay with 450 M cases or 2.1" length all you need to do is use a throater...if you want to use 458 WM cases trimmed to whatever length you like then you will have to use a 458 WM reamer, no way around it...going with a WSM changes the picture a bit.

No loosers here, just different desires and requirements.

I don't think you can get too much overkill and doing so keeps YOUR pieces and parts in one place...underkill is a whole different kettle of fish, so I want to maxinize the potential...you can't overload safely, but you can always underload.

Going to a Gibbs case will maximize the potential for sure, and if I were going after African DG and just HAD to use a levergun I would go that route in a NY second...but realistically going with a maxed out WSM/RUM/LAPUA case will get you pretty much all you need for 95% of all hunting situations no matter what continent you're on.

I like 0.125" minimum muzzle wall thickness, but 0.100" would work well enough...the pressure is well down and many rifles operating in the 40-50KCUP range have less than that at the chamber end, Ref the Marlin leverguns....I just like the look of a BIG hole and a BIG barrel, plus it adds some weight and helps with recoil mitigation.

My barrel has enough meat to handle going out to 0.510", you can run a Hoop stress analysis on 0.100" wall thickness and see how much safe margin you have easy enough, the software programs are available online on many physics links and at least one Northern Cal gunsmithing school...but to be sure I would talk to Clearwater or one of the other reborers for expert opinions.

A steel frame is stronger, but in the BLR/BAR's almost all the strength is in the barrel...the frame is just part of the structure shape...but I agree...I like the looks and feel of steel in the older steel framed rifles. I have my eye on an older steel framed 300 WM BAR to convert to something from 416 to 50 cal, but I'm waiting until I get a solid answer on the hows of barrel removal.

We're still talking about a 45 cal bullet and tons of penetration data is available online...besides all that energy that gets lost as the bullet exits is wasted, argumentatively speaking and it's what the bullet does as it's mucking about INSIDE the animal that counts so pick the bullet accordingly. Penetration and tissue destruction/organ-CNS disruption all go hand in hand.

One thing about reloading data...once you know the water weight volume of your case, you can use reloading data from ANY case with similar case volume AND caliber...as long as you use safe reloading procedures...start low and work up slow.

Short fat cases might be a bit more efficient in getting the powder to burn better, but the expanding gas doesn't care what shape the case is.

You can get some good data from Powley online programs for free...just punch in the case and bullet information and out pops a 86% "optimum" starting load. QL and Load from a disk use similar formulas to calculate load data, tweaked and tuned for todays powders.

You're on your way...enjoy your trip.

Luck

Boomie, I intend to use the throater first, then will think about moving forward with the .458 Reamer to 2.4.

FOOBAR, Yep, that is my third move. Use the WSM reamer for the chamber and check throat. May go directly to that after throat lengthening. At that point, a safe loadn and the amount of recoil I can stand will have a say. I would like to use the RUM case for maximum capability, but will have to see if the magazines can be modified sufficiently for 100% feeding. No compromise there.

Now. You've struck a chord, FOOBAR, in the possibility of reboring to .475! If the muzzle is as you say .730, that would leave .127 on each side. A little thin, but doable and maybe able to handle 60K pressures.

Would be interested in a steel rifle if it were a takedown. That keeps me with the newest model.

Ordered yesterday and am already getting antsy!

I think a long throated 450 Marlin could add some life to this diminishing cart. For under 100 yards the rifle bullets should still be in the functional impact velocity envelope.
450 marlin long throat could be a popular conversion. No extra costs but hand reaming the throat for a significant increase in useable case capacity in light bullets. Just make sure that there is enough parallel sided freebore to seat out 45-70 bullets to .8" tip to case mouth.

You will ALWAYS have a built in max length of about 2.80-2.85...maybe 2.90" with ANY case you use.

Here's a few more things to think about.

The NET case volume will be controlled by the bullet length inside the case.

If you want to use solid brass bullets then you will have to go to the lighter end and a truncated cone otherwise the bullet will almost be too long to stabilize and will be seated WAY deep in the case, LOOSING case volume. You will need a 1-20 T at least to handle the longer brass bullets.

In this application it doesn't matter which case you use, 458 WM or 450 M...they both have the same case NET internal volume at 2.80" COAL with a 1.1" bullet, and also the same NET volumes with ANY bullet seated to 2.80" no matter WHAT the length...~58 gr H20 NET volume in this case...

It DOESN'T matter what length the case is OR the case volume, which runs from ~70 gr H20 at 2" to ~88 gr H2O at 2.45"...so throating only gets you that much...58 gr H20 NET and it DOESN'T matter WHAT length the case actually is...from 2.0 to 2.5"...the NET volumes will be the same.

NET volume is what you want, not what an empty case measures...

BECAUSE of the length limitation of the magazine, the only way to gain volume is to go to a fatter case...no way around it.

A PIC of some solid brass 45 cal bullets with different shaped nose profiles I turned out on my lathe...nothing fancy...compared to a 430 gr TS hard cast lead. I turned them just to get an idea of what is required to obtain the weights and shapes I might want to use in solid brass bullet.



ANY of the 3 brass seated to 2.80" leaves ~41.5 gr H2O NET volume...~1.050" deep in the case. That's good for ~1500-1700fs, ROUGHLY, at 53KCUP. The slightly lighter 430 gr TS cast lead is good for ~2000fs at the same pressure...it's seated 0.650" deep.

I don't have any need or desire to whack ANY African game, but it doesn't matter WHAT game I take, I want to hit it with maximum killing power for all the reasons a responsible hunter should use...and I'm WAY to tight with the schekels to do the job more than once...

Luck