For my personal scoped carbine training and demonstration in courses, I find IMI Razorcore 77 grain to be the best value.
- 77 grain Sierra Match King with cannelure
- Good brass that is annealed, reloads well, and is not too soft
- Crimped primer and bullet
- Waterproof case mouth and primer
- 5.56mm pressures and velocities
- Sub-MOA Accuracy
- Less than $1 per round
- Stays out of transonic beyond 600 yards from a 14.5″ barrel
The muzzle velocity standard deviation (SD) leaves a little to be desired (averaging 15-25 fps), but it shouldn’t matter much at nominal ranges. I have pulled a few to weigh the powder charge, and they are loaded with 25 grains of ball powder.
Compared to other options: It is less expensive and easier to find than Black Hills Mk262 yet has similar performance. Black Hills also switched to the Hornady 77gr SMK clone bullet recently on its Mod 1 C. Federal 77 grain Gold Medal Match has painfully slow muzzle velocities, but is very accurate and has low-SDs. I haven’t seen good results with AAC from the students that have brought it to class.
The 77 grain Sierra Match King performs well against exposed targets, but does poorly through auto-glass, so I do not recommend it for a LE duty load. It does have all the other features needed for field use ammunition, so it’s a good round to stock up on.
Targets show typical results with my SOLGW Mk1 with 14.5″ barrel. Paper groups are from 100 yards, steel at 300 yards.
Chrono results:
- Mk12 w/Douglas-CLE barrel: 2762 fps
- SOLGW LFR 18″: 2775 fps
- LPR 16″: 2664 fps
- SOLGW Mk1 14.5″: 2630 fps
- Colt 14.5 M4: 2574 fps
