SUBSONIC 180 grain SP (soft point) flat base bullet, Sig brass, Fed 215M primer. Ammo is loaded single stage by hand and the powder weighed out individually. This bullet will stabilize in a 1:12″ twist or faster (1:11″ and 1:10″). 100 rounds per order
1050 fps in 26″ barrel (suppressed).
100 rounds per order
Why use a 180 grain Sierra SP (soft point) flat base, instead of a BTHP bullet? When shooting at subsonic speeds, bullet stability becomes a huge factor for the bullet to properly stabilize and for it to shoot well. Bullet length is a major factor in how stable it is out of the muzzle. In a given twist rate (like a 1:10″ barrel twist), a shorter flat base bullet is more stable than a longer BTHP bullet is. The 180 grain Sierra SP flat base is much shorter bullet than a similar weight BTHP bullet, like a 175 grain Sierra MatchKing. This allows the 180 grain SP flat base to be more stable and have the potential to be more accurate at subsonic speeds than a BTHP design. BC (ballistic coefficient) does not matter at subsonic speeds, so having a high BC bullet does not benefit the shooter. This is why the 180 SP flat base bullets work well as subsonic round!