This ammunition requires a barrel twist rate of 1/11 or 1/12 to properly stabilize the projectile.

ATTENTION: If you are using an AR-15 style rifle or similar rifle, and manually cycling the bolt carrier to feed Subsonic ammunition, please read the following warning. Beck Ammunition Subsonic is primarily designed for Bolt Guns.

If you experience a failure to feed, DO NOT keep dropping the bolt carrier until the round chambers. Take the ammunition out and inspect it for 'bullet set back' (bullet pushed into the case). The repeated heavy action of the bolt carrier slamming into the ammunition (that is most likely stuck on the feed ramps of your rifle chamber) does have the ability to push the projectile back into the case. If the setback bullet round is fired, the bullet may not exit the barrel, leaving you with what is known as a 'squib', or a stuck bullet in the barrel. This is also a good policy for any ammunition, including high velocity.

I Understand