The muzzle velocities for the Lake City M855A1 are summarized in the table below.
https://www.ar15.com/media/mediaFile...02-2426796.jpg
For comparison, the next two tables show the muzzle velocities for legacy military 5.56mm ammunition that also uses 62 grain projectiles: M855 and MK318 Mod 0.
https://www.ar15.com/media/mediaFile...es-2423077.jpg
https://www.ar15.com/media/mediaFile...ow-2423073.jpg
Accuracy
I conducted an accuracy (technically, precision) evaluation of the Lake City M855A1 ammunition following my usual protocol. This accuracy evaluation used statistically significant shot-group sizes and every single shot in a fired group was included in the measurements. There was absolutely no use of any group-reduction techniques (e.g. fliers, target movement, Butterfly Shots).
The shooting set-up will be described in detail below. As many of the significant variables as was practicable were controlled for. Also, a control group was fired from the test-rifle used in the evaluation using match-grade, hand-loaded ammunition; in order to demonstrate the capability of the barrel. Pictures of shot-groups are posted for documentation.
Shooting was conducted from a concrete bench-rest from a distance of 100 yards (confirmed with a laser rangefinder.) The barrel used in the evaluation was free-floated. The free-float handguard of the rifle rested in a Sinclair Windage Benchrest, while the stock of the rifle rested in a Protektor bunny-ear rear bag. Sighting was accomplished via a Leupold VARI-X III set at 25x magnification and adjusted to be parallax-free at 100 yards. A mirage shade was used. Wind conditions on the shooting range were continuously monitored using a Wind Probe. The set-up was very similar to that pictured below.
https://www.ar15.com/media/mediaFile...95-2427000.jpg
The Wind Probe.
https://www.ar15.com/media/mediaFile...db-1342522.jpg
The test vehicle for this accuracy evaluation was one of my semi-automatic precision AR-15s with a 20” stainless-steel Lothar-Walther barrel. The barrel has a 223 Wylde chamber with a 1:8” twist. Prior to firing the Lake City M855A1, I fired a 10-shot control group using match-grade hand-loads topped with the Sierra 77 grain MatchKing (without a cannelure). That group had an extreme spread of 0.56”.
https://www.ar15.com/media/mediaFile...ed-1336364.jpg
https://www.ar15.com/media/mediaFile...85-1336365.jpg
https://www.ar15.com/media/mediaFile...12-1336366.jpg
the control group . .
https://www.ar15.com/media/mediaFile...rr-2423064.jpg
Three 10-shot groups of the Lake City M855A1 ammunition were fired in a row with the resulting extreme spreads:
1.78”
2.65”
1.78”
for a 10-shot group average extreme spread of 2.07”. The three 10-shot groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group. The mean radius for the 30-shot composite group was 0.63”.
The smallest 10-shot group . . .
https://www.ar15.com/media/mediaFile...01-2423067.jpg
The 30-shot composite group . . .
https://www.ar15.com/media/mediaFile...02-2423079.jpg
M855A1 compared to other mil-spec loads . . .
https://i.ibb.co/yVsqyK5/m855a1-vs-m...groups-101.jpg
In the category of useless trivia, the M855A1 bullet cuts the cleanest holes in paper targets of any 5.56mm/223 Remington ammunition that I’ve ever tested. It’s like wad-cutters for the AR-15.
https://www.ar15.com/media/mediaFile...01-2423080.jpg
https://www.ar15.com/media/mediaFile...06-2428297.jpg
I also fired a 10-shot group at 100 yards off of sand-bags from each of the 14.5” barrels that were used in chronographing the M855A1 ammunition.
A 10-shot group fired from the Colt M4A1 SOCOM barrel had an extreme spread of 1.85”.
https://www.ar15.com/media/mediaFile...ya-2423069.jpg
A 10-shot group fired from the Bravo Company 14.5" ELW barrel had an extreme spread of 2.15”.
https://www.ar15.com/media/mediaFile...rd-2423068.jpg
A 10-shot group fired from the 14.5" Hodge Defense barrel had an extreme spread of 2.51".
https://www.ar15.com/media/mediaFile...ou-2426936.jpg
fired cases
left: from a 5.56 Colt M4A1
right: from a 223 Wylde
https://www.ar15.com/media/mediaFile..._2-2434136.jpg
Lastly, for any Internet Commandos in our viewing audience today, here’s a pic of a sub ¾ MOA group of the Lake City M855A1 ammunition fired at 100 yards. The group has an extreme spread of 0.59”.
https://www.ar15.com/media/mediaFile...up-2423071.jpg
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