Thursday, April 2, 2015

Shorter Barrels for Defensive Rifles: How relevant is the velocity loss to non-military use?

Via Oleg

5.56mmx45mm cartridge was developed with a 20 inch barrel in mind.

The original AR15 was designed around iron sights and a lightweight, high-velocity bullet. 55-grain M193 ball gave flat trajectory and reliably fragmented in flesh at velocities above 2700fps. With the proliferation of flattop rifles and optical sights, the sight radius becomes a consideration mainly for backup use. For the original barrel length, that included ranges up to 200 yards.

The shortest barrel for civilian use that is not restricted by NFA1934 is 16 inches, yielding about 150fps lower initial velocity and reducing the fragmentation range to 150 yards. The shortest non-NFA AR in common use has a 14.5″ barrel with a permanently attached muzzle devices extending the length past 16″. Its fragmentation range is closer to 50 yards. With the heavier 62-grain M855 load, these numbers are further reduced. How relevant is this loss of velocity to our use?

More @ All Outdoor

No comments:

Post a Comment