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9/22/2017 12:11:25 AM
Posted: 6/13/2005 7:46:12 AM EDT
Since the supplies of the good American Eagle .223 ammo is drying up or has dried up here also, one choice available right now is the above load.

Does anyone have muzzle velocities shot from AR15 type rifles from 14.5" up and how has it grouped with 1:7 and 1:9 twists?

How does it compare quality wise to some of the good, widely available loads?

Thanks!

Link Posted: 6/13/2005 11:29:53 PM EDT
?
Link Posted: 9/1/2005 2:54:14 PM EDT
BTT. I'd like to know too.

-KW
Link Posted: 9/1/2005 3:37:04 PM EDT
[Last Edit: 9/1/2005 3:40:34 PM EDT by ChickenKiller]
UMC® 55 MC Muzzle3240 100yrds2759 200yrds2326


These ballistics reflected a test barrel length of 24

need to get a chronograph huh? haha
Link Posted: 9/1/2005 4:42:08 PM EDT
I have a Bushy 14.5 with a 1-9 twist.

My lot of UMC chronographed at 2945 fps.

Accuracy is very acceptable.

Your rifle will vary.
Link Posted: 9/2/2005 2:01:12 PM EDT
I fired a total of 350 rounds of the Rem UMC recently. I would NOT depend on it as a quality alternative to the AE. When chronied in a 1/7 20 inch Colt, the average velocity was 3047 fps.

But one round went 2934, very slow, while another went 3216, quite hot! An ES of 282 fps is ridiculous and evidence of a serious propellant QA issue.

One batch of cases I examined showed about 3 casings of 50 or so, had blackened case heads implying primer pocket leakage. Burnt black that was still there after being tumbled a couple of hours!

Probably my fault from inattention, but I did "stub" one round when activating my bolt release. The magazine DOES have a weak spring, and the follower had tipped down in front. Anyway, the bullet was pushed back in the case at least 10 thousandths.

If any bullets being fired are getting set back during the feeding cycle, the raise in pressure might explain the hot round and blackened case heads. But NO other .223 or 5.56 I've shot recently had any setback bullets, and one problematic barrel/upper combo jammmed many a round into the feed ramps. Bent to hell, but not shortened!

In a 1/10 twist 16 inch Mini-14 the ES was still a pretty high 150 fps, again indicating erratic velocities in a completely different weapon system. Average velocity was 2920 fps.

Groups were not fired beyond 50 yards, and were unremarkable. The effects at 200 yards of muzzle velocity variations nearing 300 fps eliminate Rem UMC from any use I would have for it.

The "hot" rounds I can live without. If one round can clock 3216 fps in a 20 inch AR, that would definitely be an overpressure load for a .223, especially in a bolt gun with tight chamber.

Paladin



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