I was sorting junk in the shop (meaning downsizing) and found a .510 barrel blank with 8 inch twist. 1.250 straight blank. 26 inches.

Hmmm. Have no idea where it came from, likely in one of my trades 25 years ago.

The A Square handbook speaks of 10 inch twist barrels for high bullet rpm and increased penetration. Food for thought for you African guys.

To the point: Anyone have a thought if this barrel is worth chambering for something in 50 Cal, maybe 500 AR? I would contour the blank and put it on a M70.

I can't imagine a twist that fast for a 50 cal except for a sub sonic application.

There are several "500/510 Whisper" variations for shooting subsonic 0.510" 750gr bullets.

Likely work fine, but expect higher pressure from loads... with same relative vels

I have a CZ 550 in 500 Jeff with a 1 in 10" twist McGowan barrel. If I had to do it over again I would've gone with a slower twist rate. It's accurate as hell but you can actually slightly feel the rifle wanting to twist in the hand holding the forearm when shooting offhand. It doesn't effect accuracy but once you feel it, you always know it's there.

Thanks guys. Might turn it into reloading dies for the 500 Jeff, just received a resize reamer.

I like 14 or so twist for the 500's, have this on the 500 Jeff.

My AHR-built .500 A-Square has a barrel with a 1 in 14” twist rate. It has been great with the 570 and 600 grain mono-metal and bonded core bullets I have used.

Art Alphin used 1 in 10” twist barrels on the A-Square-built Hannibal rifles chambered in .500 A-Square.

Nothing but the .50 Browning Machine Gun round drives .510” bullets as fast or faster than the .500 A—Square. IIRC, the .50 BMG uses 650-750 grain bullets, and barrels having a 1 in 15” twist rate.

Not sure why anyone would need a 1 in 8” twist rate on a .50 caliber.

Maybe for very long, very heavy-for-caliber bullets driven at low velocities?

quote:

There are several "500/510 Whisper" variations for shooting subsonic 0.510" 750gr bullets.

quote:

Maybe for very long, very heavy-for-caliber bullets driven at low velocities?

My 510 Whisper is 1:9", only because I couldn't find a 1:8"blank! Helpful stabilizing almost 3" monometal bullets at subsonic velocities.

I would consider a single shot maybe based on the 348 case. 50 Alaskan? Long range subsonic target stuff like the old days but high tech bullets.

I sent you a PM about this barrel.