Good afternoon Gentlemen,
Can anyone refer me to the source of a chamber reamer in .495 A-Square. My Ruger RSM .458 Lott is going to 50 cal.
thanks

you could consider the 500 accel .. see my sig .. i have the reamer at hand

Can only second Jeffe - the 500 AccRel is a much better choice ....

Patrick.......

Count #3 as a vote for 500 AccRel as a much better choice as well....... Jeffe 510 looks to me to be the best of all 510s.... I have a 510 Wells, done before I knew of the 500AR, if I were doing it over again, it would be the 500AR........ And like Jeffe says, "reamer in hand ready to go"..............

Good Luck......

Michael

Maybe a fourth vote for the AccRel.

You are going to need to re-do the bolt face and to go from a .532 casehead rim to a .589 casehead rim. If you are also going to reduce the cartridge length from the 500 A2//500 Mbogo, you might as well consider the AccRel.

I would add, though, that a 0.25" parallel freebore will probably be more reliably accurate than a 1.25" freebore, so check before chambering.

As for power, the 500 AccRel can do 7000ftlbs without issue. If you want more, then I would recommend the A2//Wells//Mbogo (beltless).

I'll also give a vote for the '500 AccRel', but as Tanz alluded to, my vote is for the '500 AccRel Nyati'.

I think the 495 A-Square is an awesome caliber. Have you spoken to Harlan Satrang at Triple River Gunsmithing to see if he has a reamer?

quote:

Originally posted by Patrick Stoll:
Good afternoon Gentlemen,
Can anyone refer me to the source of a chamber reamer in .495 A-Square. My Ruger RSM .458 Lott is going to 50 cal.
thanks

Art Alphin's first 495 A-Square was done on a Winchester M70. 3.600" COaL.
The 495 A2 was dropping bull elephants using the then new "monolithic solid" of AA's making by 1978.
.510/570-grainer at 2400 fps from a 24" barrel is practical with the 495 A2, and that is "enough gun" to be using for anything.
Like a .458 Lott that took up body building.

The only reason to convert a Ruger RSM 458 Lott to a .510-cal would be to rebore the barrel and preserve the integral quarter rib.
Otherwise you would be better off re-barreling a CZ 550 Magnum, Dakota 76, get a stainless MRC M1999 PH, etc.
Or the "Be Cool," Winchester M70.

You are using a 3.8" Rigby-length action, and getting suggestions for a 3.4" cartridge above.

I once saw a Bowman-Made .505 Gibbs on a Ruger RSM.
That gun started out as the old 24-inch, fat-barreled Gen-2 .416 Rigby profile, 0.810" diameter at the muzzle, not counting the barrel-band front sight.
It changed a 10.75# .416 Rigby into a 10.0# .505 Gibbs by re-boring and re-chambering plus bolt face and magazine/feed work.

IIRC, the factory .458 Lott Ruger RSM is to be had only in the late, great Gen-3 Ruger RSM.
IIRC, that 23-inch barrel has a .750" muzzle diameter.
And that rifle weighed right at 10.0#, IIRC.

.750" diameter at 23-inch length is on the thin side for a re-bore to .510-caliber.

All of my "fifties" (.510 and .500 calibers) have a barrel profile of at least 0.800" at 24" muzzle, and thicker than that if the barrel is shorter.

Oh, no .495 reamer here, but I am sure Dave Manson could make one for you, with any throat you want.
If I were reboring my fat-barreled RSM .416 Rigby to a "fifty" that would be a nice cartridge for it, with magazine length to spare.

My favorite "fifties," all of which could be fitted into an RSM action, are:
500 Mbogo, 500 A2, 500 Bateleur, .505 Gibbs, and 12.7x68/49-10.

quote:

Originally posted by capoward:
I'll also give a vote for the '500 AccRel', but as Tanz alluded to, my vote is for the '500 AccRel Nyati'.

Aye...

Thanks for the replies gents.
My reasons are "for the fun of it". I took the Ruger Lott, new in 2012, to Moz for 2 buffalo, sable and misc other game. 500 A-Frames at 2,250 feet. Great to shoot, but at 11 lbs scoped, a pound heavier that I like. I have Mod 70's, several, in WM, 416 Rem and 375 H&H. This big Ruger is very smooth, a good piece of wood, nice qtr rib and worth doing something fun with. In keeping with the Lott, belted, nice smooth taper and easy feeding, the 495 A2 is an easy conversion and I love the feel of it in my hands. The barrel is a good size all around, The magazine was build for the Rigby, I have CH4D dies, brass, and as someone suggested, Ranson will make a reamer from CH4D's drawings. My goal is a bolt action .500NE.
Thanks for all your comments.

If the re-boring firm OK's the job, i.e., the barrel contour is big enough, go for it.
And let us know who is doing the re-boring.
The 495 A-Square would be excellent, capable of either 500 NE ballistics at low pressure for a bolt action,
or capable of much more.

You will probably lighten a 10-pound .458 Lott to a 9.5-pound "Big Fifty" by re-boring.
Those are dry/bare/empty rifle weights, no scope, no ammo.
That's good.
That is as light as I went with 500 Mbogo No. 2, on a CZ 550 Magnum with 23" No. 6 Sporter contoured Pac-Nor 1:9" twist.
My other "Big Fifties" are 1:10" or 1:12" twist.
They work fine.
I like a little faster than the common 1:15" twist, for slower than 50 BMG velocities with the monometal bullets.
Fast twist does not hurt in a 50-cal DGR.

Art Alphin used 1:10" Twist on his 495 A2.

Have you selected a twist for the re-bore?
.458 Lott RSM is 1:14", and that would be better than a 1:15".

You will also be able to plink with 50 BMG bullets, any of them, if you have a throat like on the standard 500 A2.

If you get hold of the .495 A-Square reamer specs, please share the throat dimensions here.

500 A-Square has .511"-diameter parallel-sided free-bore that is 0.400" in length, with leade angle of 1.5 degrees.
That is a great throat for an all-purpose "Big Fifty."

quote:

Originally posted by RIP:
If the re-boring firm OK's the job, i.e., the barrel contour is big enough, go for it.
And let us know who is doing the re-boring.
The 495 A-Square would be excellent, capable of either 500 NE ballistics at low pressure for a bolt action,
or capable of much more.

Same oal as the 500 Accrel.. And if you don't PAY ART he will sue you

quote:

Originally posted by jeffeosso:

quote:

Originally posted by RIP:
If the re-boring firm OK's the job, i.e., the barrel contour is big enough, go for it.
And let us know who is doing the re-boring.
The 495 A-Square would be excellent, capable of either 500 NE ballistics at low pressure for a bolt action,
or capable of much more.

Same oal as the 500 Accrel.. And if you don't PAY ART he will sue you

Jeffeosso,

You say the 500 Accrel has the same COaL as the .495 A-Square?
That would be 3.600".
Or are you saying you can load the 3.4" 500 AccRel to 3.6" length, by seating the bullets out, long-nose style?

If AA is suing over reamer infringement,
then make a "500 Stoll" reamer FOR 2.810" BRASS LENGTH INSTEAD OF 2.800" BRASS LENGTH OF 495 A-SQUARE.
Then you can trim your brass to 2.800" minimum and use the same max spec for 495A2 as your minimum spec, same dies and brass.
The .505 Empire was like a .495 A2 but with .505 bullets ... etc.

Isn't it great, I ask a simple question and 13 posts later we have invented a new cartridge and named it after me. Capitalism at work.
I initially will use AA's "any shot you want" as my guide. CH4D supplied my dies and has drawings available for reamer production. I will report on the conversation with the reamer guy. I may look to Pacific Tool and Gauge for this. Any comments out there.
Thanks to all.

I have had many reamers made by Dave Kiff of PT&G, as well as Dave Manson of MPR, and a few from JGS.
Have talked to both Dave's by telephone in getting wildcat reamers made, or minor changes to existing proprietary and wildcat reamers.
Both men are good at what they do.

Dave Kiff/PT&G did the 12gaFromHell-3.85" reamer which fits RMC brass with 209M primers perfectly.
Dave Kiff/PT&G did the 20gaFromHell-3.5" reamer likewise.
Dave Kiff/PT&G put a new throat on a 300 Lapua reamer per my specifications.
I have used a standard Dave Kiff/PT&G .338 Lapua Magnum reamer with various removable pilots and various neck and throat reamers for various purposes.

But I have done more "wildcatting" business with Dave Manson/MPR.

JGS:
I got a standard .500 A-Square reamer from JGS back in the late 1990s.
I got a .408 Chey-Tac reamer from JGS last year.
Both of those are proprietary cartridge reamers made to proprietary standards,
and nobody sued anybody over that!

JGS probably has the specs for the .495 A-Square already on hand, maybe a reamer on the shelf ...

But if you have CH4D dies already, better stick with your current plan:
Get the specs used by Dave Davison/CH4D to Dave Kiff/PT&G, or Dave Manson/MPR is good too.
The Three Daves



I have CH4D die sets doing good work for these cartridges:
470 Mbogo
400/.395 Nitro Express 3-Inch Aboriginal aka "10.03x75R"
400 Whelen Petrov of 2003.

The CH4D 400 Whelen dies were originally called "400 Whelen JGS" dies, sitting on the shelf at CH4D.
They had been made to match a 400 Whelen reamer made by JGS.
That reamer had been made to match the G&H rifle chamber cast done by Michael Petrov in 2003.
RCBS also made dies to match that chamber cast/JGS reamer.
RCBS refers to that specification as the "400 Whelen G&H."
It was all good.

I forgot I had this reamer drawing. Found it buried in a stack.
Dave Manson, used to call himself "Loon Lake Precision," now "Manson Precision Reamers."

"Standard" specifications, has a pretty short throat, only 0.150" length of parallel-sided free-bore,
should be accurate with hunting bullets.
With these specs, you will not be able to seat the Hornady 750-grain A-Max out very far though, maybe only 4.25" COal.

Down to the nitty-gritty of the .495 A-Square chamber. My reamer is on order but weeks away. Thanks to Mr. RIP for the Manson drawing. My problem is with Cutting Edge bullets and similar monos, 570 grain solids, they require seating into the powder column or out until the front driving band is into the rifling. Either choice isn't ideal. While the .460 Weatherby case seems cavernous, at 50 cal it's really just adequate. The STD drawing calls for a parallel throat of .150. Not enough, .175 would be adequate but .200 is a good number. Mr AA is emphatic that any mod to a standard chamber requires ID on the barrel. I'm not opposed to say ".495 A-Square .2". Sounds kind of wimpy though. Would you go to the trouble?

By all means make AA happy, if that is all it takes.

".495 A-Square Special Throat"
or
".495 A-Square 0.200 P-S Free Bore"

To be more exact, you are only changing the length of the parallel-sided free-bore, just one component of total throat.

I would go whole hog and make the parallel-sided free-bore length equal to one-half of the bullet caliber: 0.255"
That is my prescription after 15 years of wildcat experimentation.

When I long-throated a 500A2, I had the reamer made with a 30-degree shoulder instead of the standard 35-degree shoulder,
and had the barrel elaborately engraved by a professional engraver:

".510/460 Weatherby Improved Jenkins and Berry"

If you are going to make it special, might as well make it obvious.

495x.2000 or. 2500

With deference to those African authorities who assume the cartridge name on the barrel should match the brass headstamp, I will stay with 495 A-Square in the usual location and then, on the other side, describe the very special nature of this rifle with something like "Special .200 throat for mono-metal solids", elaborately engraved of course. I like it.

It's taken a while, but the parts and tools are now at hand. Thanks to all for the helpful comments and suggestions. I used PT&G for the reamer. I'm about to send the RSM to Jim Dubell at Delta Gunshop for the boring and conversion.
Comments on recent experiences with Jim would be appreciated.

Fun to read through this thread! I like shoulder-
less cases, be they belted, rimmed/flanged or
rimless and beltless that headspace on the mouth
while being held in place by the claw extractor.
I believe our 458hubel has proven longer case
life with such designs. And accuracy is more than
adequate with a properly done build. I remind the
opening poster that michael458 has proven on
dangerous game kills that .280 sectional density
is PLENTY at 2200 FPS or a bit higher with CEB
.500" diameter bullet choice, and even on down
to the smaller .41 calibers if I recall. So a .510"
diameter bullet at 510 grain weight with CEB or
similar quality and type competitor will be fine
for you P.S. Enjoy your rifle sir!

The big Ruger is now in hand. I visited Jim Dubell last week and was presented with more than I could have expected. Jim bored the barrel, chambered it and importantly, made it feed. The nearly invisible quarter rib joint is as new. I provided Jim with Ruger parts, from Brownels, follower and magazine for the .416 Rigby, similar in size to the parent 460 Weatherby case, and dummy rounds in Hornady softs and mono solids. He used a combination of mine and his own to make it feed. And feed it does. I ran a few rounds yesterday, my 570 grain loads at estimated 2,200 fps, the smell of 100 grains of Reloader 15 blending fragrantly with the pines and firs, as the booms echoed up the draw.
It was immediately clear that the Ruger stock has to go.
So, my questions today is: to stock for open sights or scope as this is not a round that lends itself to compromise.

first - congrats on the "new" rifle -- you will enjoy it a alot -

next, as some of my friends have found out, GC cast loads can go 2300 easy...

rl15 is actually too slow.. it is grossly inefficient in the 500accrel and must less h335 delivers much more vel

Rip -i had though the 495 was 3.35 not 3.6 .. as i have now researched and found it to be a 2.8 case, then of course it is about 3.6 ..

which means nearly .3" of case wasted

Yes, congratulations.

I agree with Jeffeoso on the powder, though I would go even faster. For the 500AccRel I found H322 to be better, and I prefer extruded to ball. I've recently picked up some H4198 that I hope to try in the Fall.

On a stock for a scope or not, it's your personal call. I see better and have done all of my hunting with scopes, so I would go that route, and have scopes on hog-backed CZ 416's which shoot similar energy rounds (6200ftlb [though recoil is technically a factor of momentum]). I guess I adapt to a rifle.

I shoot my 500 Jeffery with both open sights and more regularly with a Leupold 1.5-5x on Talley QR med height rings. You do want plenty of eye relief

Many thanks for the comments. Regarding gun powder, I'm using Any Shot You for load data. I'm a bit shy about going it alone. Mr AA uses three powders over a fairly broad burn rate range, R-15, IMR- 4064 and H-4895. I'll go with 4895 for two reasons, reducing loads to the 500NE fps range and further reductions for cast bullet fun shoots. Hodgdon's work and recommendations (60% rule) for reduced loads with H-4895 is on point for this application.
Regarding stocking, in my view the only reason to play in the .500 crowd is to emulate a stopping rifle and I'll stock accordingly. As a .458 Lott, it wore a 1.5X5 but as a .500
we'll go open sights and drop, butt shape/size accordingly. I'm 6'2" and require a lot of drop to get a good full shoulder plant. That much drop just doesn't lend itself to a scope and at these recoil levels, it's just no fun to compromise. I do love the raw power conveyed with each round and the smell of the gunsmoke.

I use an H4895 load out of Any Shot You Want for my 500 Jeffery as well. Stay within the recommended ranges, if you go too low you risk hang fires (ask me how I know that!). I really like the 495 A-Square as a cartridge, nice choice!

and only use federal 215 or 215m ... to avoid hang fires - ask me how i know

Yup forgot to add that part thanks jeffeosso

Well, I'm going to try Winchester LRMag primers, because I ran out of Fed 215Match. I've seen good reviews.

On stocks, 'hogback' is a good style for comfort, and MonteCarlo works, if you are not doing "American classic" almost level. But do not try out a military-type straight drop. That may work on light rifles but can punch your cheekbone. Ask me how I know. On a real big bore the rifle must not recoil into the face bones.

Thanks for the comments gents. I do love the feel of the big A2 round in my hand.
The Any Shot You Want loads using H-4895 are all a little hot for my goal. My check of a fired round seating a Hornady 570 grain bullet gives 100 grains of H-4895 at 100%. That's convenient. I will likely go to 90% as I reach for 2,150 fps from my 23" barrel. With fed 215 primers, I wouldn't expect a hang fire even at 80%, as I may go there with cast bullets. Is this contrary to your experiences?
The stock dimensions are beginning to take shape as I work my way through my gun rack and library.
I'm fortunate to have Calico Hardwoods a few blocks from my office and have spent some time with their inventory. I previously found a good dense, straight grain blank with a little fiddleback for a .375 H&H a couple years ago. My rifle with the Ruger stock is running about 14 ozs light from my goal of 10 1/2 lbs.
It's fun.

I got a hang fire with 95g of H4895 pushing a 570g TSX in my 500 Jeffery at 2000 fps using Jamison brass and Federal 215 primers. Since then, I don't go lower than 101g which gives me about 2200 fps, but have standardized on 103g which gets me to 2300 fps out of a 24" barrel chronographed at about 15'. Not sure about the case capacity of the 495 A-Square compared to the 500 Jeffery but I wouldn't go any lower than the starting load in the book. Your mileage may vary ...