Posted On: 10/18/11
A: Yes, these 77gr SMK BTHP projectiles are loaded to what is called "magazine length," and can be safely loaded into and fired from AR-15 magazines.
Posted On: 10/4/11
A: It is not recommended to fire 77gr .223 ammunition through a 1/9 twist barrel, for the twist rate is not sufficient to stabilize the projectile. While this may vary from barrel to barrel at short range, it would certainly be noticeable with all 1/9 twist barrel at long range. You might find that your 1/9 twist barrel will perform well with 75gr ammunition, but it will certainly stabilize 69gr BTHP as loaded by a number of manufacturers. All three projectile weights are capable of high accuracy at range, but wind drift is greater with the lighter projectiles, which have lower ballistic coefficients.