Minimum barrel length and twist for XM193

[User Name]

A rifle that is capable of stabilizing heavy (75 - 77 grain) .224" bullets is automatically set up to stabilize lighter ones. You absolutely do not need another rifle "set up" differently.

I am truly mystified as to why this subject continues to cause so much confusion and misunderstanding.

Understood.

[User Name]

[QUOTE=BushmasterFanBoy;70219]I really only have 55gr. FMJ, I use .223 for plinking, and keep around 1100 rnds of assorted 5.56 pressure stuff on hand for whatever needs it. Most of the 5.56 stuff I have is Guat, its my "go to" ammo, despite it being foreign made, I think the 5.56 pressure is a bigger advantage than using domestic ammo.

I've shot 3000 rounds of Guat. in the last 6 weeks never had a problem myself. Apparently from what I gather there is nothing wrong with XM193 what so ever as a defensive round. It seems to be an apple and oranges debate. Like what is better 124 P+ 9mm or 147 gr 9mm?

[jmart]

A rifle that is capable of stabilizing heavy (75 - 77 grain) .224" bullets is automatically set up to stabilize lighter ones. You absolutely do not need another rifle "set up" differently.

I am truly mystified as to why this subject continues to cause so much confusion and misunderstanding.

For AR velocities and especially when talking FMJ you are absolutely correct. But it is a real issue when talking faster stepping .22's, thin-jackets and heavy bullets. In those instances the bullets will fail in flight. But again, for .223 don't sweat it.

[DRich]

Not to go off topic, but since most of you guys prefer "rarer" loadings like 75+77gr. not to mention various loadings in the 60's, is there anything particularly wrong with 55gr FMJ?

Nothing "wrong" with 55gr FMJ, but the heavier loads have proven to be more effective performers. Just depends on your particular needs and expectations.

I'd trust M193 spec ammo for just about any general purpose need, but I choose other loadings when I want greater accuracy, effective range or terminal performance.

[Alpha Sierra]

But it is a real issue when talking faster stepping .22's, thin-jackets and heavy bullets. In those instances the bullets will fail in flight. But again, for .223 don't sweat it.

That was one of the caveats that I mentioned.

That said, the only in flight failure I have experienced was with 6.5 mm Hornady 95 Vmax at around 3100 fps. They blew up inside of 50 yards. Not a problem with velocity, but of shooting them through a barrel with a twist faster than necessary. Caliber: 260 Remington. Barrel: 28" Krieger six groove with 1/8 twist for shooting 120 to 140 grain match bullets.