The standard 500A2 throat has something like 0.4" of freebore.

I have one with 0.3" of freebore and it will handle the 650 to 700 grain Milsurps including AP and ball with target accuracy out to 1000 yards.

I have another one that has about 0.587" freebore, and it will allow me to seat the 750 grain A-Max out as far as it will go.

All of these throats have about 0.3" of leade in addition to the freebore.

As for twist, 1 in 10" works great with 570 grainers (FN, XLC) at 2500 fps and 750 grainers at 2250 fps.

2150 fps may be best with the 700 to 750 grain target bullets.

You need a faster twist when you are shooting 50 BMG target bullets at lower velocities than Ma Deuce Browning does.

Don't listen to anyone who says the 15" twist should be used.

The excess twist helps the shorter/lighter 570 grainers penetrate better when hunting big game with a 500 A2.

10" twist is what A-Square used on their rifles.

The 50 Peacekeeeper also uses a 10" twist.

Case closed.

Great, thanks.

What about the freebore for the Peacekeeper, is it much longer?

Are the A2 and Peacekeeper exactly the same except for the freebore, could I use A2 dies for the Peacekeeper?

Is there any reason to choose the Peacekeeper before the A2?

Thanks again RIP