Most of my Colt 14.5” M4 barrel data was lost in a tragic boating accident, but about the best one can hope for using match-grade ammunition in a free-floated Colt 14.5" M4 barrel is 1.25 MOA and averages will be higher.
The data below shows the results from two different Colt 16” M4 profile barrels using match-grade hand-loads.
One Colt 6920 barrel tested from my bench-rest set-up at a distance of 100 yards using match-grade hand-loads produced three 10-shot groups fired in a row that had extreme spreads of:
1.42”
1.19”
1.56”
for a 10-shot group average extreme spread of 1.39”. The mean radius for the 30-shot composite group was 0.44”.
The smallest 10-shot group . . .
The 30-shot composite group . . .
Another Colt 6920 barrel tested under the same conditions as described above produced three 10-shot groups fired in a row that had extreme spreads of:
1.59”
1.55”
1.73”
for a 10-shot group average extreme spread of 1.62”. The mean radius of the 30-shot composite group was 0.54”.
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