So I want a 50. But I want one that will shoot .510 mil-surp bullets. Assuming I'm limited to a 4" magazine and a .648 bolt face, what's the most powerful .510 wildcat I can build? What kind of muzzle velocity can I expect with 750 gr. bullets? (And yeah, I know I may have to single-load each cartridge.)

This would be on a Montana Pro-Hunter action, if that helps.

Pertinax

You can shoot .510 mil-surps in the .500 Jeffery/11.2x72mm Shuler, but I couldn't tell you what velocities you'd get with 750gr. bullets.

Why not just get a .50BMG Ferret upper (available in LH) and attach it to an AR-15 lower?

George

If you were to neck Rob's 600 OK down to 50, it would be the biggest case you could use. I'll take a SWAG, and say you'll be in the ~2300 fps ball park with 750's, with a 505 based cat, I'd think 2200, and with a 500 A-sq, 2100. If you go with a 28" tube, you'll pick up a little speed.

I had my 500 Jeffrey deep throated for 50 bmg milsurp, but I have yet to work up any loads for them.

I don't know that I'd go with the 600 OK cat though (no offense to Rob), you'll gain 100+ fps over a 500 A-sq, but once you get past 460 Weatherby brass, you don't have a consistant supply of brass. Though with CZ coming out with a 505, an improved gibbs case in .510" might be another reasonable option.

If I did another 50 cal, it would be the 500 A-sq, being to call up supply houses and get brass off the shelf is a big plus over a case that "we'll get some more in a month".

Actually the .600 Ok necked down to .510 will do about 2400fps with a 750 A max. I am building a unlimited class gun on this cartridge as we speak. Accuracy has been outstanding at 1000 yrds ( .5 MOA to date)
Horneber .600OK brass will be available thru AHR(406-961-4944) in the next few weeks.-Rob

I have a couple 500 A2's (.510/.460 Wby) and that is plenty of kicks for me, thank you.

If I were to do another .510 bore,
.510/.505 Gibbs would be it.

The .408 Chey-Tac is based on the .505 Gibbs case head, but beefed up. As a .338 Lapua is to .416 Rigby, so is the .408 Chey-Tac to .505 Gibbs.

If I could lay in a good supply of .408 Chey-Tac brass from Jamison, that would be sweet.

Well, with that Montana PH action-- could I do a .600 Overkill? (Why stop at .50!) I'm looking for an excuse to put one of those actions on order, but I want somthing BIG-- bigger than I can build on a Win M-70 action.

quote:

Originally posted by pertinax:
Well, with that Montana PH action-- could I do a .600 Overkill? (Why stop at .50!) I'm looking for an excuse to put one of those actions on order, but I want somthing BIG-- bigger than I can build on a Win M-70 action.

I lose interest after .510.

I agree with Ron, my 500 Jeffrey cured me of any desire to go bigger. I'd have to use a break, or make the gun really heavy, and either of those were unacceptable to me. The componet cost and available also go up logrithmically once you pass 50 cal. I just couldn't see going with a gun that would cost me twice as much to build and feed, and I'd shoot it even less.

You just might want to shoot one of the monsters before plunking down several thousand dollars to build one.

I disagree with you guys! After doing a bit of hunting with the 585 NYATI and .600 OK on Deer,Pigs, ELAND and meadow Grizzly's, I continue to find the BIG stuff far more entertaining and unbelievably effective than .510 stuff. I've really never found the 500A2, Jeffery, 505 Gibbs etc that much more dramatic on game than a 470NE or 460WBY. The .600OK is in a different class ( Hydraulic stops on marginal hits become possible). Yes they are not for everybody, but the effects are nonetheless impressive! -Rob

Rob,
sure wish you could make it next weekend to SEE!!!

Jeffe

quote:

Originally posted by Robgunbuilder:
I disagree with you guys! After doing a bit of hunting with the 585 NYATI and .600 OK on Deer,Pigs, ELAND and meadow Grizzly's, I continue to find the BIG stuff far more entertaining and unbelievably effective than .510 stuff. I've really never found the 500A2, Jeffery, 505 Gibbs etc that much more dramatic on game than a 470NE or 460WBY. The .600OK is in a different class ( Hydraulic stops on marginal hits become possible). Yes they are not for everybody, but the effects are nonetheless impressive! -Rob

I'm not saying the on game performance for the ultra big bore isn't there, just that I'm not willing to live with the type of gun required to make a ultra big bore shootable. I find the 500 Jeffrey with 600 gr loads in a 10 1/2 pound unbraked gun is my limit. I guess I'm a pansy

WARNING WARNING WARNING

Testtosterone over load! Testosterone overload!

Oh Ray,
we know you top out on a 404!!!

jeffe

quote:

Originally posted by GeorgeS:
You can shoot .510 mil-surps in the .500 Jeffery/11.2x72mm Shuler, but I couldn't tell you what velocities you'd get with 750gr. bullets.

Why not just get a .50BMG Ferret upper (available in LH) and attach it to an AR-15 lower?

George

Now George, be nice!

Nice? I'm serious.


Slap one of these bad boys on an upper, and you're ready to rock!

George

Down the road I will put my 510 HE in a
Ruger #1 with long heavy barrel, and weighted to 16 lbs...
My only rimmed HE wildcat, with brass made from 475 #2 3.5 inch brass, straightened out.
Case 3.55 long.Rim .630, Base 5.77.Rim can be bigger, but I reduced it to use in bolt action.
Over 11,000 ft lbs. 600 gr at 2900,
750gr at 2600 fps.
I already tested it in Enfield bolt action,
as a single shot with
a couple lengthened cases, to hold 12 gr more
powder.Got 600 gr soft to 3000 fps..Ed.

hubel458,

Aren't those loads equal to the 50BMG, in weight & speed

Hog Killer

I've thought a little on this subject. Looks to me like the Gibbs case could be made to hold about 170g of water and still have .45" for a neck. You'd end up somewhere around 4.7" COL, but that's a lot of powder behind a 750g.
For the Wby case, 105g gives you about 2200 fps with the 750g, so figure another 25% more powder and you should top 2400 fps, right?
Rob, that's some impressive marksmanship on your part, considering the world record for the BMG these days is somewhere around .6 MOA, right?

Oh, also there's the T-Rex case, which for 750g A-Max and the like is plenty long for a 4" COL. That would give you about 180g water under the neck, at only 4" COL. If you're interested in single-shotting it, this would definitely be worth consideration.
Not that this case is easy to come by in any sense of the word. But at .688" casehead it should fit in the PH no prob.
I'm guessing the A-Max is about 2" long. That would give you about 155g of water under it, or maybe 130g powder.
Where's QuickLhen you need it?

Bwana-be

I think the record might be just under 5 inches but that is a 10 shot group. Not sure. The blokes on www.longrangehunting.com will know for sure.

My limit is 375 without a brake and 460 with brake. That is where I can shoot the rifle from a rest and don't have to make compromised because of recoil, except of course for hearing protection.

For shooting offhand etc then I can do a 460 without the brake.

Mike

Hog Killer-They are about 85-90% of bmg.
But case is a special great shape, works really good with DB Ball powders like H-414
and W-760.No shoulder to force the
use of a real slow powder, etc.Ed

Horneber 600 Ok brass will be available from Ed Plummer at American Hunting rifle in 60 days.

Dak

Worlds record in .50BMG is .27 MOA. an even better score has been shot by Lynn Mcmurdo but it was ruled ineligible. The .27 MOA group was Shot by Skip Talbot at Raton NM a few years ago. Same exact load I use( Skip likes to beat us fair and square). That humiliation is a regular occurance. I've shot quite a few <.6 MOA groups( approaching 10 now at 1000 yrds and those records are in the public domain on FCSA.org so I'm not lying) and won smallest group at RENO two shoots ago. This is with three guns ( light, heavy, unlimited) that I built myself. Beacause I can't read the wind for shit yet, I can't do better than about 1 MOA consistently. I do believe a .600OK necked to .510 is more akin to a 6ppc in design( short fat case and high BC bullet) and inherently more accurate than a .50BMG( The .50 Mcmurdo is a shortened, 40 degree shoulder version of the .50BMG by the way). However, it will be slower by 300fps and less wind resistant. I am thinking of asking Skip to shoot my .600/.510 at Reno in a match and seeing just what it's capable of in the hands of the master.-Rob