This allows the 55 grain SP flat base to be more stable and have the potential to be more accurate at subsonic speeds than a BTHP design. The 55 grain SP flat base is a much shorter bullet than a similar weight 55 V-max or BTHP design. In a given twist rate (like a 1:10″ or 1:9″ barrel twist) and slow subsonic speeds, a shorter, flat base bullet is more stable than a longer BTHP or VLD match bullet of the same weight. Bullet length is a major factor in how stable it is out of the muzzle. Why use a 55 grain SP (soft point) flat base, instead of a BTHP, VLD, polymer tip or match bullet? When shooting at subsonic speeds, bullet stability becomes a huge factor for the bullet to properly stabilize and for it to shoot well.
#Thermold subsonic 223 full#
If you are zero’d at 100 yards with normal full power supersonic 223 or 5.56 ammo, your point of impact (POI) with the subs will be about 9″-12″ low at 100 yards. It will shoot fine if you manually cycle the bolt. The 55 grain SP bullet is marginally stable in a 1:12″ twist barrel at subsonic speeds, and should not be shot in any slower twist rate. If you have a 1:12″ twist, you will need to check bullet stability first before shooting through a suppressor. This ammo will NOT cycle an AR-15!! This ammo is designed for 1:10″ twist or faster (1:9″, 1:8″. This subsonic ammo is not designed for barrels longer than 24″. This ammo is loaded to SUBSONIC speeds for barrels from 10″ to about 22″ barrels. Once-fired LC brass, Hornady 55 grain SP (soft point) 1030 fps. Our top selling 223/5.56 SUBSONIC round (priced per 100 rounds).