PTR stated that late 2015 going forward all newly manufactured barrels would come with the US 5/8 X 24 threaded barrels rather than original HK spec 15 X 1 threaded barrel. As long as you have a 2015 or newer model, you will be able to use this muzzle device.
The Fortis Manufacturing 7.62MM R.E.D. Barrel Muzzle Brake is designed to have the "F" logo facing the correct way up. If you need assistance properly timing your muzzle device, email us at Techsales@opticsplanet.com.
The Fortis Manufacturing 7.62MM R.E.D. Barrel Muzzle Brake might work with a .300 Win Mag. However, since Fortis does not state if the Fortis Manufacturing 7.62MM R.E.D. Barrel Muzzle Brake is rated for .300 Win Mag pressures I recommend contacting Fortis to determine compatibility. I also recommend the VG6 Precision Lambda PRS30 Muzzle Brake at the link below for a 300 Win Mag.
https://www.opticsplanet.com/aero-precision-vg6-precision-lambda-prs30-muzzle-brake.html?_iv_parent-caliber=dot-300-winchester-magnum
AS long as the thread count is the same this should be good to go.
Yes, as long as your barrel is also 5/8x24 threaded.
No it does not.
It depends on what the thread pitch is on the muzzle of your barrel. If it is 5/8x24 threaded, it will fit.
It depends on what the thread pitch is on the muzzle of your barrel. If it is 5/8x24 threaded, it will fit.
Assuming the barrel is 5/8x24 threaded, yes this should work as the bullet diameter of a 300 RUM is the same as 308 WIN (7.62x51).
This muzzle device is is 5/8x24 threaded. Your AR-10A should be 5/8x24 threaded, however you should verify directly with the manufacturer of your rifle to confirm.