Others would have a lot more expertise than I but I'm thinking the Achilles heel is how strong the bolt is. Smaller calibers can get away with higher pressure because bolt thrust is not so much an issue but larger bores shooting heavy bullets might be too much depending on the bolt. See what the manufacturer and some of the other big bore auto guys are saying about this. My guess is 45k psi will give a longer life to the bolt.

quote:

Originally posted by boom stick:
That 50 super short 405 BBW#13 @ 2,000 is sweet! Seems 43 grains of Lil Gun will be the sweet spot. An excellent in the thick defensive gun cart combo
I can't help but think a 410 Super Short would duplicate the 405 win of 300@ 2,250 ish

Boomy

Yes, I think 43 Lilgun and the 405 is probably the place to be overall. But I had to see if I could get over 2000 fps with the 405 and stay just under, which it did. I am sure that 43 would be 2000 and be a bit less pressure, which I must try again. As you see this is yet another indication that we are in fact getting to top end pressures, not much velocity gain from 42 to 44, but a big jump in pressures! One takes all things into account.

Also, take notice a couple of times I hit some high pressures, one as much as 70000 PSI, at no time did the cases even get slightly sticky, worked easy and slick extraction. The cases are strong, being cut off WSM and RUM for the other larger B&Ms. Many times I have made mistakes to 70000 PSI and have few issues with extraction or problems in the other guns as well. Being in the 60000--63000 psi is very safe, max up to 65000 safe.

No 410 Super Shorts. Bullets are just too long for magazines under .458 caliber. So from the official B&Ms, there wont' be any under .458 caliber. Just not enough versatility down under that.

M

quote:

Originally posted by boom stick:
Others would have a lot more expertise than I but I'm thinking the Achilles heel is how strong the bolt is. Smaller calibers can get away with higher pressure because bolt thrust is not so much an issue but larger bores shooting heavy bullets might be too much depending on the bolt. See what the manufacturer and some of the other big bore auto guys are saying about this. My guess is 45k psi will give a longer life to the bolt.

Jim and Boomy

I think I will start and stay with the 50000 PSI mark and see what happens. Personally I really don't care too much about these things, until I get them on the range and shooting. They are quite fun to play with, once you get them to where they need to be. Weighing in at 10-11 lbs with scope you need some sort of "Transport" to get them to the range and back. HEH HEH HEH...... Far as I am concerned rather useless things they are, but I must try and please folks that like them, so I am stuck with doing the data at some point. Not putting a tremendous amount of effort into it, low priority to me, other things have much more priority, so I work them in as I do other things.

M

Hello All,

Well once again Michael has amazed us with his ability to create wonderful data. Does this man have a real job besides buying shampoo? He pretends to but I don’t believe it.
As an engineer, I love to play with numbers. At North Fork, we have our measures of determining good powders and loads for a given cartridge. Once determined, we test for accuracy. Now granted, we may miss something, but in general, this is a very good method with 12 years of development, plus, we need to make bullets. Let it be known, like Michael, we believe penetration is everything. If you can’t to the boiler room from any angle, then you are limiting your ability to hunt effectively.

Lets look at the 50 B&M AK (Michael’s data):



Impressive to say the least. On the far right, I have calculated Average Speed, Speed per Pressure, Speed per Powder Weight, and finally and the most important, Speed per Pressure times Bullet Weight per Powder Weight or Momentum divided by the product of Pressure and Powder Weight. This is what we call the Load Efficiency. In terms of “real” engineering, it does not mean a damn thing and the units are nonsense, but so are most “bullet” measurements beyond momentum and energy (i.e. Taylor KO, Keith, etc.). These are all empirical by nature and seem to follow a trend and it can only be discovered after significant amount of testing. What we look for are loads that are above .30 (higher the better) or what we call 30% (please note again, the calculation does not really come out as a percentage due to the fact it still has units attached to it – lets please not get into a fight as to who’s method of measurement is best – this is ours and it is what we use).
I have rearranged the data, placing the highest efficiency loads at top. Again, .30 is the goal and we try to design our bullets such that no matter the powder/loading, the bullet will allow give an efficiency above .30 (we are not always 100% but we strive to be).



Conclusions: Yes, I am an engineer so I always need a conclusion. At the lower pressures needed for a lever gun action, the lighter brass bullets have significantly less bearing surface and have much greater speed and lower pressures. Thus, their efficiency rating is great. A caveat is it is harder to compare mismatching bullet weight but we trust our formula from years of work.

Lets look at the 50 B&M Super Short data:



Amazing how much pressure will influence the performance of the cartridge. Who would have thought you could use so much pistol powder with such great success.



Conclusion: At higher pressure, it may be argued that brass over copper begins to show higher pressures per same speed and weight. But for a bolt gun, it may not matter. Besides, both bullets have stretched the performance of this cartridge far beyond what ordinary bullets could do. This is like arguing who was the best heavy weight fighter, Mohammed Ali or Mike Tyson. Both were the best and both had significantly different fighting styles. That is how I look at the bullets Michael has developed (with Sam and CEB) and ours. We differ on some things (I like my bullet to stay together), Michael wants his famous star pattern. We could “debate” all day, but in the end, neither will be persuaded (due to all of our testing) so why not have a nice Scotch and discuss hunting. We do agree that penetration trumps everything else and two holes are better than one. Both of these bullets will kill effectively every time. Straight line penetration breeds confidence. Confidence leads to better shooting. Better shooting puts money in everyone’s pockets.
Let us know your thoughts.

Regards,

North Fork Technologies
www.northforkbullets.com

North Fork

I can't see your photos or charts or whatever, and I want to see them!!!!!!!

Michael

I obviously have some troubles. Here are the pictures in order for above.

http://farm7.static.flickr.com...597_103efa5dbd_s.jpg
http://farm7.static.flickr.com...136_dc27b42af1_s.jpg
http://farm7.static.flickr.com...960_117edf8ced_s.jpg
http://farm7.static.flickr.com...547_6a45a391da_s.jpg

Holy Crap what in the world is going on.

Try it yet again.

http://www.flickr.com/photos/66107454@N08/6012404597/
http://www.flickr.com/photos/66107454@N08/6012952136/

Keep working on it. those are so small look like someone trying to write on rice!

OK those last two are better can almost see those!


If you want, they are jpgs, email them to me I can post them. Looks like excellent stuff!

And for the 50 B&M Super Short - although the above links you can just scroll over once in Flickr.

http://www.flickr.com/photos/66107454@N08/6012951960/
http://www.flickr.com/photos/66107454@N08/6012404547/

quote:

Originally posted by North Fork:
Holy Crap what in the world is going on.

Welcome to our world--



SSR

I should note, that this simple calculation does not tell us anything about accuracy nor does it say anything about each individual contributor. This measures the system. To truely measure the difference between components you can only vary one thing at a time. That is why Michael's data is so great! (Notice on the gun rags how loadings between different bullets also have different powders or were loaded with different powder weights even for the same bullet weight - that way the manufacturers cannot be angry at the magazine showing their true performance relative to someone else's)

Michael - I will email you the pictures.

www.northforkbullets.com

North Fork

EXCELLENT WORK!!!!! I love it! Especially when I see so many .30 or better, heh heh!!!!!

I do see however that you just had to go and "hi-light" all of the "Over Max" pressures as well,thank you very much! LOL....... Gees, could have not added those, much less have to go an hi-light them?

HEH HEH,,,, Ya'll see there on the chart that I have a new primer, a Fed 120? Ever heard of one of those? Bet not! That's a top secret primer I have been working with Federal on recently and it's kinda like a magic primer and is specifically designed for the B&Ms!!!! Do you see that, I think it's on the Super Short chart! Hmmmmm, you say?

OK OK---I have one finger that is a little faster sometimes than the other, and instead of 210--sometimes it comes out 120! That's all, there really is no top secret primer, that was just BS! LOL......

Also, I did just now receive the charts via email so Thank You. I will study them more tomorrow a bit more in depth. Looks like a great body of work! Interesting as well!

Now some points to ponder. You are correct, the BBW#13 and our North Forks are not quite matching in weight, material and some other things as well. As you well know, you put a lot of time into designing the new North Fork bullets for the B&Ms, and you did a damned good job at it too. In both the 50 B&M and the 50 B&M Super Short I am able to achieve higher velocity with less pressure with the North Fork bullets than the brass CEB BBW#13s. Both being what I would call Non Conventional, speaking now of the CPS and the NonCon. Both work in different ways, and both per given weight actually penetrate to near the same distance, or so close that it does not matter. CPS (B&M CPS) expand and transfer trauma in that matter, along with deep and through penetration, while the BBW#13 blows petals transfers trauma and continues to penetrate as well. Both bullets absolutely devastating and above ANYTHING, deep and through penetration, which absolutely, we both concur is required to be successful. Now lets' look at the super shorts, and what WAS available for any of them. Conventionals and not constructed heavy enough to do heavy work for sure. Now, with the North Fork CPS and the BBW#13s, this has enhanced the Super Shorts to far more than they would have ever been capable of in the past. I would have no issues, concerns or problems at all taking any of the Super Shorts for buffalo now, with these bullets! WHY???? Penetration! It's there! With penetration one cannot fail! Penetration first, transfer of trauma next. That we have, with both bullets.

quote:

Michael wants his famous star pattern

Well, yes and no to that actually. As for blowing the blades, I am not so sure which is better, or if it makes a big difference whether they go off in a star pattern away from center wound channel, or if they stay within the center wound channel doing even more destruction. I have seen both ways, and as far as transfer of energy to an animal I can't see a difference in animal reactions. Both are dead as hell and lot's of trauma transferred, and devastation to vital tissue unequaled. On a bullet with blades, yes I want shear, brass or copper, and because of that shear, penetration increases, I want that penetration!

I don't want a shear on the CPS--I want it to do exactly what it does, ROLL backwards, but only to that 1/4 of the top of the bullet and mash and pulverize it's way through, destroying everything in it's path. Velocity such as the 500 MDM can churn up does not hurt this bullet, it rolls back and over and penetration increases continuous with velocity. As does trauma transfer. The 450 CPS we have primary for the 50 B&M is incredible in the 50 and will for sure slam buffalo to the dirt. In that 18 inch gun I can run 2350 fps with a 450 gr North Fork CPS and be well under max pressures! That is nothing to sneeze at gents, and .500 caliber at that. Buffalo don't have a pray against that. I cannot run any other similar weight bullet to that velocity and keep pressures below max. So we have an excellent deal going on with that bullet, and the exact same thing is going on with the 50 Super Short and it's designed 375 CPS from North Fork, and I will use this next year on those Australian buffalo. Along with the other Super Shorts, 458 and 475! The CPS will be up front. And I will also be using the BBW#13 s as well. Hopefully with over 50 buffalo or more on quota, no bullet will go short of use!

Thanks for this great body of work again. It looks great, but it is getting late on the "Right" side over here, and my bed time! So I will look more tomorrow.

Oh, and by the way, I will be conducting our little test we talked about yesterday in the morning, so I will have those results tomorrow for you!

Thanks North Fork! No worries, there is room enough for two quality bullet makers in the world, and as far as I give a damn, that's North Fork and Cutting Edge Bullets--both of you are great at looking after our Big Bore Interests, and I am sure everyone here is thankful for both of you, I know I am!

Michael

Before I head off to roost, I just want you boys to take note of something! When does other bullet manufacturers come and participate with us Big Bore guys and talk bullets, cartridges loads, pressures things like that???


Ever seen them? No you have not! Sometimes they are lurking about, you can believe that, but none of them give a damn about it anyway, not enough to actually come and find out what actual shooters really need or want. If they lurk, they only lurk because they want to see what threats are out there for their bottom line! Other than that, they could care less, they prove it all the time!

I think we should appreciate and support those who do care, and those that actually listen to what we need!

Good Night!
Michael

Yep life is good...CEB visited yesterday and NF today. Now if we can get Dr J back on board all will be well.

quote:

Mike458,"Before I head off to roost, I just want you boys to take note of something! When does other bullet manufacturers come and participate with us Big Bore guys and talk bullets, cartridges loads, pressures things like that???".

Mike, i think you really hit the nail on the head with this quote. Applicable to many manufacturers of much of the equipment we, as hunters, use, more specifically rifles and bullets. I think the mutual co-operation between the shooters/hunters and NF & C.E.B, involved in this thread and the T.P.B thread will inevitably benifit all of us and I for one am truly grateful to ALL.

In response, in the future I will be ensuring that the barrels of neither my Lott nor 500 M.D.M will be poluted by anything other than N.F's and C.E.B's.

P.S I remember meeting some of the N.F fellas in Dallas, nice fellas to boot ! hope to meet Dan some day.

Paul

For sure the North Fork boys are First Class all the way! And yes, we had a blast at DSC with them!

quote:

hope to meet Dan some day.

Dan and CEB crew I think will be in attendance this years DSC. I hope to put CEB and North Fork together, can you imagine what a team they would be? Hmmmmm?

Well in the meantime, Dan, his son Nathan, and a fella named Bob, all from CEB dropped in for a visit a week or so ago. We had a blast, so meet Dan, Nathan and Bob!




And of course here is Dan and Sam




Dan, Nathan and Bob did not have a lot of Big Bore experience before their visit, I think maybe they have shot a few 338s small bore things, but little real big bores. So nothing would do but Sam brought down a bunch of his doubles for them and I covered them up in B&Ms and a few things I had laying around. Somehow I missed getting photos of them shooting the doubles, and they started out with those first, I think I had to run into the office for something, but I don't recall?

I did not, on purpose, give them any big bore shooting lessons, pretty much just handed them a rifle and said go shoot! First, unless they know what they are doing wrong, then how to learn to do it right? Kinda like throwing them in the pool and letting them drown first, then teaching them how to swim! Sorta anyway!

Poor Nathan, I just happened to bust him with the 510 Wells and get a good photo of "afterwards", Bob did about the same thing, I just did not catch it!








Well after this little incident, and lot's of laughing at poor Nathans expense, a tad bit of instruction took care of all these matters afterwards!

Look at these stances now

This is Bob--Before Instruction





This is Bob After Instruction



Bob is a sharp fellow, catches on quick!

Dan let the little maple 50 rock him just a bit, but he caught on quick too when it came to the 510 Wells.







We had a really good visit, had lot's of fun! Nathan was so impressed with the rifles that he is getting himself a brand new 458 B&M, it's one I had here that just came in recently!



Michael

Great pics Mike, thanks for posting.

Looks like the fellas from C.E.B could do with Herd Reduction hunt for some "in-field" big bore "hands-on" ???

Awesome little 458 Nathan picked up, all business like ! Those guns are WICKED !!

Hey Paul

I think they are getting some practice in for sure.

I sighted Nathans rifle in today, and it was a easy chore, moved the sights one time only, and it was good to go. Shooting 480 gr CEB BBW#13 Solids Dead center at 25 yds--for the heavy stuff, and 400 gr BBW#13 Solids a tad high just above that. Iron sights are good to go, rifle headed his way.



Talked to Wes today about my bastogne stocks, still at the checkering place--coming soon! While Wes had me on the phone he ended up getting some more of my money today too! He had two more gorgeous bastogne blanks come in, I could not say no, so I have them put aside for B&Ms of some sort?

How about your rifles? Any news on the export yet??? Has to be close!

FYI--Not such good luck right now with the Horneber 500 MDM brass! Seems a little soft, not holding 500 MDM pressures well. I am waiting to get the pressure trace rifle back from Wes so I can run pressures and see how far it goes. Looks like we have to keep 500s under 2250 fps right now to use that brass, guessing 50000 PSI is max with it! Little disappointed in that so far.

Michael

Mike, that little 458 of Nathans really looks the goods. Very practicle carrying, all-weather, hard-use rifle with plenty of punch !
I'm sure he'll get a lot of fun out of that one.

Bastogne stocks ??, mmmmm, your getting flash in your advanced age, what are they going on ?

No news yet on my rifles, might actually send off an e-mail today to see what's going on.

Dissapointing re the Horneber brass. Limiting to 2250 will be o.k for a while but no point having a Masserati if your going to have to stick to the speed limit !!

Best regards to all at home,

Paul.

Oh Lordy! Horneber screws up too?
My .395 Tatanka brass from QualCart must have been pulled off the basic line at Hornady before it got hard enough.
That was a disaster!
I can only hope to shoot them and size them enough to harden them before they hurt me!

"FYI--Not such good luck right now with the Horneber 500 MDM brass! Seems a little soft, not holding 500 MDM pressures well. I am waiting to get the pressure trace rifle back from Wes so I can run pressures and see how far it goes. Looks like we have to keep 500s under 2250 fps right now to use that brass, guessing 50000 PSI is max with it! Little disappointed in that so far."

Paul

Yes, my memory is getting worse these days, I don't even recall exactly why I built it or the circumstances around that little 458 B&M Ultimate? Just showed up one day? Hmmmm? Anyway, it will make Nathan an excellent starter into big bore rifles for sure. He is already in contact with Wes to have a wood stock built too. Have the best of both worlds, plastic and wood!

Yes, I am on a bastogne kick right now, we will see how they turn out, have 3 at checkering right now. One is going on a 500 MDM Stainless, One is going on a 50 B&M Stainless, the other will be in waiting for a new 475 B&M Stainless--waiting on barrels right now so it's behind.

Also, the entire 475 B&M project is going to be behind right now. Somewhere I had a miscommunication with Brian on the neck and shoulder and it turned out not exactly right. Sam and I found out trying to make brass for it. So that is busy being corrected, but requires reamer and starting over on the damned dies! Oh well, things happen!

RIP

Yes, this is just preliminary right now, no full test done, but I am sure it is too soft and it will not handle 500 MDM loads. It will handle 50 B&M loads at least in a 500 MDM. Wes has my pressure trace rifle fitting that stock to it, so when I get the pressure trace rifle back I will put the brass thru the ringer and find out what the upper limit is.

I have had good luck with brass in all the short guns, little quirk with Quality here and there with the first shaving off! Second run of Hornady brass in the short guns is great. But not good in the 500 MDM of course! 500 MDM likes it's parent cartridge--375 RUM, and damned particular about any changes and not very tolerant of other brass! I swear, I think I will take a dremel tool to the 375 and I have some hammer stamps just put a 500 in it's place, and tell anyone that don't like it to kiss my ass! There is but one reason to worry with it, and that's idiots in other areas, so I swear that's what I am going to try! And use nothing but the RUM brass! Thing is, in many many hunts across the globe I have never had anyone actually compare head stamps with barrel stamps, but, BIG BUT, it don't take but one idiot somewhere to cause a problem. I was told that RSA was looking hard at this before I left, so all my 500 MDM and 458 B&M was head stamped, every piece. Arrived at the airport and Police, my ammo was in the bags with Momma outside the airport and not even in the room with the rifles, they never even asked about ammo! Check serials, see ya later. Zimbabwe they tried their best to count it--but even that seemed to be a problem--1-2-3-6-11-, wait, let me start over! HEH HEH HEH.......

Michael

Fortunately, the 500 Mbogo brass from QualCart was good, and it was based on Hornady basic also.

Glad I passed on getting some "proposed" Horneber 49-10 (12.7x68mm) brass.
I just like that .338 Lapua Magnum brass so much, never a problem, stoutest stuff going ...
I will figure out a way to fit a "49" on the .338 Lapua Magnum case,
and make the barrel stamping match:
"49 [L] .338 Lapua Magnum"
(the [L] represents the Lapua shield logo on the headstamp)
aka
"49-Bore/.500-Caliber/.338 Lapua Magnum Improved of 2010"
aka
49-10
aka
"12.7x68mm Tornado"

My other easy ones:
.395 Ruger
.395 H&H
.398 Lapua Magnum ... just a stroke of the engraving pen on some good brass.

I wanted the brass badly, mostly for the guys that want the B&Ms and don't wish to encounter issues or possible issues when traveling. As for myself, like I said, in many many trips across the pond, zero problems, zero issues. Does not mean it won't happen the very next time. So crap, I am going to skin some off of 375 RUM and scratch 500 on it somehow, and they can do as they please. Seems the RUM brass is about all that is going to work correct in the 500 MDM.

I had several rifles stamped or engraved on the barrel various things, 50BM/300 and things like that, until no one ever even looks! So quit.

Michael

Michael,

Hopefully you’ll get your 500 MDM with the pressure connections back shortly. Hopefully Horneber will make things right regarding the brass once you can document that the brass doesn’t hold up to the 375 RUM’s CIP’ PMap.

Also, haven't had a chance to putz with the 300 RUM brass yet but will by this weekend.

quote:

Posted Aug 15, 2011 2:06 PM Hide Post
Dave,

They’re the “forgotten child” of the B&M lineup…but if the 458 B&M cartridge is to long for the BLR box, Michael already has a solution on the shelf for you. It is the 458 B&M SA cartridge. The 458 B&M SA uses the 300 SAUM case length, 2.0” case length, so it slots nicely between the 2.4” case length 458 B&M and the 1.65” case length 458 B&M SS. I think the overflow case capacity of each is (approximately); 458 B&M = 99gr, 458 B&M SA = 85gr, and 458 B&M SS = 70gr respectively. Performance wise, in a bolt action rifle the 458 B&M SA performance should be very similar to the performance difference between the 300 WSM and the 300 SAUM cartridges using identical bullets and identical barrel lengths.

Although Michael tagged the “SA” as "Semi-Auto" as he chambers them in his DPMS Semi-Auto rifles…it just happens to be the optimum solution for the various "Short Action” bolt action rifles that are chambered for either the 300 SAUM or 300 WSM (or any of the full case length derivative SAUM or WSM cartridges)…and yes this would not be the M70 Winchesters. LOL…

quote:

Cappy, now you may be on to something. However, I think we should leave this here. I think RIP is a little tired of our 450 Marlin discussion. I'll check it out with Michael. Now, back to bullets! Big Grin


Dave
DRSS
Chapuis 9.3X74
Krieghoff .500/.416 NE
Blaser .470 NE

quote:

Posted Aug 15, 2011 2:46 PM Hide Post
Yep normally we'd be having this type discussion over on this thread:
416-458-50 SS-50 B&M Series Cartridges/Rifles
http://forums.accuratereloadin...43/m/9111029801/p/27


Jim coffee

"Life's hard; it's harder if you're stupid"
John Wayne

OK, I brought us over to the B&M thread with this. Really not an issue with me, and I am sure not RIP on TBP, but is more pertinent here I suppose.

Capo
Thanks, and yes the little 2 inch 50 B&M SA and the 458 B&M SA are the "Lost Children" maybe better termed "Black Sheep" of the B&M Family! HEH..... Since they are designed for that big Semi Auto DPMS, and that is just not one of my favorite things, although quite fun I admit, but they are very large rifles, heavy and I am just not that in to those things anymore. Damn, I have the 458 B&M SA in hand now, and I have some loads sorted out to start working on data, but have not done so yet. I must get busy on that.

Both of these are 2 inch RUM cases. They have some power behind them, no doubt about it. I dare say I will be able to exceed the 450 Marlin even in the DPMS rifle. I don't recall case capacity, I got it the other day, but have forgotten already.

Our buddy Daryl in Australia had one built. I fought it pretty hard, it was on a Remington SAUM, I finally relented. I shot it a few times as well before sending to the FFL to send to the exporter. WOrked very good. I was just fire forming some cases to see what they looked like.

Michael

quote:

Originally posted by michael458:
[QUOTE]

Posted Aug 15, 2011 2:06 PM Hide Post
Dave,

They’re the “forgotten child” of the B&M lineup…but if the 458 B&M cartridge is to long for the BLR box, Michael already has a solution on the shelf for you. It is the 458 B&M SA cartridge. The 458 B&M SA uses the 300 SAUM case length, 2.0” case length, so it slots nicely between the 2.4” case length 458 B&M and the 1.65” case length 458 B&M SS. I think the overflow case capacity of each is (approximately); 458 B&M = 99gr, 458 B&M SA = 85gr, and 458 B&M SS = 70gr respectively. Performance wise, in a bolt action rifle the 458 B&M SA performance should be very similar to the performance difference between the 300 WSM and the 300 SAUM cartridges using identical bullets and identical barrel lengths.

Although Michael tagged the “SA” as "Semi-Auto" as he chambers them in his DPMS Semi-Auto rifles…it just happens to be the optimum solution for the various "Short Action” bolt action rifles that are chambered for either the 300 SAUM or 300 WSM (or any of the full case length derivative SAUM or WSM cartridges)…and yes this would not be the M70 Winchesters. LOL…

quote:

Cappy, now you may be on to something. However, I think we should leave this here. I think RIP is a little tired of our 450 Marlin discussion. I'll check it out with Michael. Now, back to bullets! Big Grin


Dave
DRSS
Chapuis 9.3X74
Krieghoff .500/.416 NE
Blaser .470 NE

quote:

Posted Aug 15, 2011 2:46 PM Hide Post
Yep normally we'd be having this type discussion over on this thread:
416-458-50 SS-50 B&M Series Cartridges/Rifles
http://forums.accuratereloadin...43/m/9111029801/p/27


Jim coffee

"Life's hard; it's harder if you're stupid"
John Wayne

OK, I brought us over to the B&M thread with this. Really not an issue with me, and I am sure not RIP on TBP, but is more pertinent here I suppose.

Capo
Thanks, and yes the little 2 inch 50 B&M SA and the 458 B&M SA are the "Lost Children" maybe better termed "Black Sheep" of the B&M Family! HEH..... Since they are designed for that big Semi Auto DPMS, and that is just not one of my favorite things, although quite fun I admit, but they are very large rifles, heavy and I am just not that in to those things anymore. Damn, I have the 458 B&M SA in hand now, and I have some loads sorted out to start working on data, but have not done so yet. I must get busy on that.

Both of these are 2 inch RUM cases. They have some power behind them, no doubt about it. I dare say I will be able to exceed the 450 Marlin even in the DPMS rifle. I don't recall case capacity, I got it the other day, but have forgotten already.

Our buddy Daryl in Australia had one built. I fought it pretty hard, it was on a Remington SAUM, I finally relented. I shot it a few times as well before sending to the FFL to send to the exporter. WOrked very good. I was just fire forming some cases to see what they looked like.






These are Daryl's rifles that he is exporting to Australia. No sights as you see, the reason for this is that he is taking the barrels down to 14 inches when he gets them to Australia, and then will put the iron sight on there.



Michael

Not sure as I have never examined a magazine on a BLR, but I would venture to say the 458 B&M SA would be a perfect fit if they have done any in a WSM cartridge.

This is the 50 B&M SA DPMS, the parent of the 458 B&M SA

Michael, I think Cappy was right. The .458 B&M SA might just work in the BLR if it headspaces on the shoulder and it looks like it does. Case length is the same as the 450 Marlin. Can you tell me what OAL of a loaded cartridge is?

Moved from the TBP Thread:

quote:

Originally posted by boom stick:
458 B&M 2.24"
Nominal 45-70 bullets .45" tip to crimp
2.69" minimum oal.
Why would this not fit in a BLR?

I believe the issue is that the BLR has a limited internal length magazine more in common with the short action rifles – the M70 WSM action is truly an intermediate length action – which limits the cartridge length to pretty well under 3” overall. The recommendation to use the 458 B&M SA cartridge is a simple solution to the issue as it allows full use of the heavier B&M designed bullets seated optimally rather than seated deeper and they’ll still work in the SA magazine. Velocity loss between the B&M Long and the B&M SA is the same loss difference between the 300 WSM and the 300 SAUM using identical bullets and identical length barrels…a true difference but not a substantial difference.

Hey Michael,
Black Sheep works well…we just won’t refer to the cartridge as the B&M BS… I still have a SS M77 SA 300 SAUM that’ll be built as a 458 B&M SA one of these days.

Dave,
I’ve been playing (again) with QL and QT and it appears that the little 300gr Barnes TTSX BT out of the 458 B&M SA will have virtually the same bullet drop at 350yds as does the 180gr Barnes TTSX BT out of the 308 Winchester (20” barrel loaded at just under PMap). The 300gr does arrive a few hundred fps slower than the 180g…but as Michael showed us back on page 164:


there'll be plenty of bullet expansion upon arrival.
Post corrected.

Cappy, I just ordered an extra magazine for my 450 Marlin. If Michael says it is okay, I will send the magazine down to him and have him see what fits.

quote:

Originally posted by Dave Bush:
Cappy, I just ordered an extra magazine for my 450 Marlin. If Michael says it is okay, I will send the magazine down to him and have him see what fits.

Dave

Yeah man, send it down we will check it out proper and see what the scoop is!

I wonder if there is a difference between the 450 magazine and one that is for the WSM cartridge--In length?

I also wonder?? What changes would have to be made to a 450 gun for a RUM based case? Probably not much in the bolt at all? Would a WSM BLR magazine fit in the 450 gun, or is the action altered significantly?

I wonder a lot of things sometimes!
Hmmm

M

The WSM mags would be the way to go.
The SA would be a better "fit" for going from bear buster 450 marlin to buff buster 458 B&M SA. How about calling it the SABM over BMSA? SAMB? BASM?

quote:

Originally posted by michael458:

quote:

Originally posted by Dave Bush:
Cappy, I just ordered an extra magazine for my 450 Marlin. If Michael says it is okay, I will send the magazine down to him and have him see what fits.

Dave

Yeah man, send it down we will check it out proper and see what the scoop is!

I wonder if there is a difference between the 450 magazine and one that is for the WSM cartridge--In length?

I also wonder?? What changes would have to be made to a 450 gun for a RUM based case? Probably not much in the bolt at all? Would a WSM BLR magazine fit in the 450 gun, or is the action altered significantly?

I wonder a lot of things sometimes!
Hmmm

M

Michael, as far as I know all the short action magazines are the same and there is no alteration of the action for the WSM cartridges. My dealer has one in a .243. I'll run down and take a look at it tomorrow and see how it compares to the 450 Marlin.

Dave:
Thanks for your assistance on the magazines. On the lever forum, there was a thread about lengthening the .450 Marlin magazine by cutting back on some block at the rear of it. Does this ring a bell?

From Boomy (w/.458 Win Mag added)
Overflow case capacity of each is (approx):
458 B&M = 99gr
458 Win Mag = 93gr
458 B&M SA = 85gr
458 B&M SS = 70gr

Michael:
I agree that deep seating bullets is not the best way to go, but considering the increased powder capacity and not using anything over 400grs, it might be an OK deal. I still am interested in the .475 B&M. Oh, and thanks for letting me know about this thread and moving things over here. Sometimes I can be a dummy.
Max

quote:

From Boomy (w/.458 Win Mag added)
Overflow case capacity of each is (approx):
458 B&M = 99gr
458 Win Mag = 95gr
458 WSM = 90gr
458 B&M SA = 85gr
45-70 Govt = 79gr
450 Marlin = 74gr
458x2" American = 73gr
458 B&M SS = 70gr

I added a couple of additional cartridges for comparison.

Dave

For the B&Ms to work in the BLR, I think the best chance one has to make that work proper would be with a rifle chambered in WSM. Or at least WSM magazines. I may be wrong, like I said, I never even laid hands on a BLR, but just knowing how things work, a little anyway, I think one of the rifles in WSM would be an easy convert to begin with.

But, I would think that length is pretty much the same in these? I think a B&M cartridge will fit in a 450 Marlin magazine, might not work proper, but get an idea of what could be done anyway. ????? We can see.

I think Max is going active hunting down a BLR in one of the WSMs. I might help find one too.

Magazine length in WSM has to be at least 3.00 inches, if you keep to 400 gr bullets in the 458 B&M, or less, then I think it will work fine, in fact, easy. Many of the larger bullets by CEB will work as well, I know I load the 450s and 480s to 2.95 and work dandy in the M70s.

Does anyone think the BLR can handle 60000 or so? I don't know. If so, then you would have a power house with the 458 B&M on a lever gun!

Michael

I think I mentioned the other day that I bought some NEW bastogne blanks from Accurate Innovations! Wes sent some photos. They look good to me, I bought them, or traded actually, Wes and I have a trade going on, these eat up the rest of the trade and then some! HEH.... I could not refuse them!





Excellent
Michael