Friday, November 30, 2012
M193 vs. 7N6
5.56x45 M193 and 5.45x39 7N6 Factory Chronograph Velocity and Energy Comparison
Figures used are from the AR15.com factory chronograph data chart, found here.
Data used includes only "real" M193 and 7N6, all from 16" barrels. Also included is M193 performance from 20 and 14.5" barrels, those being common military barrel lengths.
Lowest Chronograph Averages:
M193 (16"): 941 m/s, 1,578 J (XM193 LC 03)
M193 (20"): 954 m/s, 1,621 J (Q3131A)
M193 (14.5"): 879 m/s, 1,378 J (Q3131A)
7N6 (16"): 946 m/s, 1,534 J (Russian)
Highest Chronograph Averages:
M193 (16"): 976 m/s, 1,698 J (Q3131)
M193 (20"): 998 m/s, 1,777 J (Q3131)
M193 (14.5"): 912 m/s, 1,482 J (XM193)
7N6 (16"): 961 m/s, 1,584 J (Bulgarian)
7N6 trails almost negligibly behind M193 for velocity, in general possessing velocities only up to a percent and a half slower than that of the American cartridge. With its slightly lighter bullet, 7N6 produces between 3-7% less energy than M193, from 16" barrels. Given the Russian cartridge's greatly superior ballistic coefficient (40% higher than that of M193), this small disadvantage in energy can be all but overlooked.
Interestingly, the lauded Q3131A ammunition from Winchester is actually slower, for a given barrel length, than even Russian 7N6 ammunition. Bulgarian 7N6 ammunition, which is fairly common stateside, produces significantly higher velocity, and even more energy than the "gold standard" Q3131A.
This is NOT intended to assert that 5.45 is "better" than 5.56. Whether either cartridge is better than the other is determined by the context in which "better" is relevant. e.g., I consider 5.45 to be a superior cartridge design, but for defensive use, from AR-15s, using civilian ammunition, the .223/5.56 is clearly better (Black Hills doesn't make a Barnes 62gr TSX load for 5.45). However, the widespread opinion that 5.45 is "anemic" compared to 5.56 is wrong, and mostly based on inexpensive civilian 5.45 ammunition, versus hot M193 fired from 20" barrels. All else being equal, the two cartridges are highly comparable.