AR 15 is a muzzle device necessary?

[MachIVshooter]

It's not the threads themselves. It's just the fact that you have to turn the barrel down to such a small diameter at the muzzle.

Like I said, as long as it's not so thin that the muzzle is flaring, it's not an issue. A .338 with 1/2-28 threads would like have a problem, but all else being equal, an unthreaded .300 win mag will not shoot any differently than a 5/8-24 threaded .300 win mag.

Many medium bore sporters already have the same or thinner wall thickness at the muzzle as a 5/8-24 .30 cal. My 700 BDL S/S .375 RUM has a .650" muzzle diameter; that's .137" walls. A 5/8-24 .30 caliber with an undercut to .575" will have .133" walls. It varies with cartridge and barrel length (as well as barrel material), but generally speaking, there's no problem going a good bit thinner. I thread 7mm and .30 cal. barrels 1/2-28 routinely, and they've never suffered accuracy loss with .074" wall thickness at the undercut.

 

[grampajack]

Like I said, as long as it's not so thin that the muzzle is flaring, it's not an issue. A .338 with 1/2-28 threads would like have a problem, but all else being equal, an unthreaded .300 win mag will not shoot any differently than a 5/8-24 threaded .300 win mag.

Many medium bore sporters already have the same or thinner wall thickness at the muzzle as a 5/8-24 .30 cal. My 700 BDL S/S .375 RUM has a .650" muzzle diameter; that's .137" walls. A 5/8-24 .30 caliber with an undercut to .575" will have .133" walls. It varies with cartridge and barrel length (as well as barrel material), but generally speaking, there's no problem going a good bit thinner. I thread 7mm and .30 cal. barrels 1/2-28 routinely, and they've never suffered accuracy loss with .074" wall thickness at the undercut.

I've seen evidence to the contrary. If I don't have a good reason to need a threaded barrel I prefer leaving the profile intact at the muzzle.