My brother is getting a 36" bbl from Pacnor, they have a 12 or a 18 twist. He's using a Ruger #1 and throating the Jeffery chamber for BMG bullets, the 750 A-Max.

Load From A Disk program says a 16-17 twist is necessary. I don't know if the program is conservative in it's calculations or what, if it was, the 18 twist might work... What a chance he'd be taking though, I'm thinking the 12 twist is the safe bet?

I've seen people on here use 10-12 twists in there Weatherby based 50's shooting BMG bullets, hope you all could recommend a solid yes or no to the 12 or 18 twist.
I think it will hold 10gr more powder than the WBY case, pressure wise, I'm not sure if it will take as much as the WBY though... the extra bbl length may offer the only additional gain... what do you all think? I'm thinking 2500 with a 750 grainer.

Thanks guys!

Go with the 12" twist, 18 is ok with 535's, but not the heavier stuff. Mine has a 15" twist, though I haven't had a chance to see if it is sufficient to stabalize BMG bullets. I think it'll be ok with the ball rounds, but too slow for the VLD bullets.

If you decide to use any military surplus bullets for general plinking, you may want to stick with a lower twist rate, or you may shed jackets on occasion.

Thanks guys.

Decissions...

Paul, who made the 15 twist bbl for you, it sounds perfect for all the bullets?

12 twist does seem unnecessarily fast, ya think it would shed jackets though? I just think the 18 twist is "too" slow but, if someone out there's having success with them and they ain't keyholin, it's hard to argue with.

My 416wby is a 14 twist and only calls for something like an 18 though, it shoots amazing to say the least... no problems are apparently related to overstabilization on that one.

Brent,

I believe it is a Douglas. I've never heard anything about the fast twist shedding jackets, and there are a few folks on this boars shooting the 500 Asquare with fast twist deep throat tubes launching the mil surp pills 2200 fps.

I don't know what type of velocities to expect from a long tubed Jeffrey, but 2500 may be possible with a 36" tube. The neat thing about the A-square and the Jeffrey is even in sporter length barrels, you get 70-80% the velocity of the BMG, but only burn 1/2 the powder.

Right on Paul, thanks again for the help and insight!

Mine's 1-18... and will handle up to 650s...

but, Wayne Doudna made me some 535 gaschecked HARD leads that I am running at 2200 fps as my cheap load. 14� DELIVERED...

that, with surplus powder (see my post in cast bullets) I can shoot for less than 30�

far far far cheaper than 30� delivered on 650 grain bullets

jeffe

Thanks Jeffe,
I'll let him know about that too. It don't get cheaper than that!!

Waynes bullets are nice,I ordered 200 750 grainers from him,bullets only cost 30.00,but the shipping was 41.00! Still cheaper than 585 jacketed bullets.
My 2 pennies,why not build a 500A2, wby brass alot cheaper than 500 jeffe brass more plentiful also,something to think about.

I have a .500 A-Sq with the 10" twist. I have used H-4831sc filling the case. I haven't chrono'ed the loads but it shoots perfectly. One winter awhile back I fired one up at about an 80 degree angle at night into clouds.

{Yes I know this isn't supposed to be done, but I live in the frozen equivalent of the deep Sahara desert.}

It went perfectly straight and the ultra dazzling red tracer was lost in the clouds and lit them from inside with a pleasant "afternoon" glow. It made me warm inside.

A 36 inch barrel on a Ruger #1? WoW! I only use a 34 inch on my Heavy class .50 BMG. With that said, 1;10-1:15 twists all work with mil surp bullets. While you at it consider a 505 Gibbs case or better yet a Chey-Tac case blown out to .50BMG. Now that should cook!-Rob

Roger,
I know what you're talkin about, had some tracers for the '06 and fired them over the glacier one night when we up there.... seemed like they went straight as an arrow till they disapeared, I was amazed!

Rob,
I wish he would look at the Chey-Tac case, the one I measured weighed 164gr water and would be sweeeeet necked to 50! Dave has the Jeffery reamer and it's cheaper to start with, I think he isn't worried about the extra speed the 408 case would obviously add, he just want's another 50, on a smaller case this time.

I looked at doing a 338 on the Jeffery case, i' didn't see the advantage with it over the Wby case though. The 408 would be the top choice if all out velocity was wanted with a 300gr SMK though. I'll build one of them soon. I'll be playin with the 338 Lapua Improved this winter.

Thanks again guys, I think the 12 twist will work best for him if he's goin heavy.