Today I chronographed some “Black Hills Ammunition” “seconds”. It comes in a white and black box and the side is labled “New Ammunition 5.56MM 77 GR. MATCH HP”.
There is a disclaimer that says “The ammunition in this package has been classified as seconds because of cosmetic imperfections such as minor discoloration, dents or scratches. Functioning and safety are unaffected.”
The cases are headstamped with “LC 2012” and the NATO cross.
I fired 2 10 round strings out of a compass lake upper with a douglas chrome moly 1 in 8" twist heavy barrel (20" long).
String 1 averaged 2609 fps. String 2 averaged 2664fps. This was measured about 10 feet in front of the muzzle using a CED M2 chronograph at 2000ft above sea level, temp 59 F and pressure 30.17" hg.
Is the black hills “commercially sold” mk262 lower velocity than the true mil-spec stuff? Is there some other reason my velocities would be that low? Also I just realized that it doesn’t actually say “Mk 262” anywhere on the package, it was just listed that way on the website of the place I ordered it from.
My BH Red Box Mk 262 averaged a little over 2,800 fps out of a 18" Noveske SPR barrel chambered 1x7 NATO. Pressure signs were on the “to warm” side for me. I got bright ejector marks on the case head with some metal splinters coming off the edge of most of the rims.
My 2,700 fps 77 gr reloads are more accurate. Maybe you got the good stuff, or your barrel is a little slow, or the chronograph reads slower than it should.
That load shoots in the high 2500s to low 2600s out of my 16" barrels. That’s off the top of my head, but is close.
I would contact BHA directly with your barrel info and ask for their input. Probably best to have the lot# for your ammo as well. Telephone: (605) 348-5150
Thanks for the responses, shootist~ and Skintop911…
I’m not complaining much about the accuracy, I guess. It was giving me ~ 1 MOA, 5 shot groups at 100 yards with iron sights and without trying too hard (service rifle setup). I just thought that it was odd for it to chrono at 2650 fps while being marketed as mk 262 5.56MM and wanted to make sure I wasn’t missing something, either in my equipment or with the ammo.
I think the chrono is pretty accurate and the barrel seems to be ok; It’s a brand new rifle w/ the upper built by compass lake engineering so it should be good, I would think. I was also getting 3140 fps out of Federal “XM193” and 2870 fps out of American Eagle “AE223H” 55gr .223, which seems to be pretty close to what other people get with those rounds from 20" barrels. The chrono also measured some pistol rounds within 10fps of spec (although I realize they’re much lower velocity).
I will consider calling black hills, thanks for the phone number.
Thanks to everyone for their continued resonses. I’ve only been shooting "AR"s for about 3 months and this is the first chance I have to choronograph any of the rounds.
Thanks for the replies and assistance everyone, I took the chrono out again and got a 2699 fps 10 round average from the Black Hills, granted it was 20 degrees Fahrenheit warmer outside today. That’s still a little bit low but I’m now suspecting my chronograph might be reading 2-3% low at rifle velocities, despite my best attempts to set it up properly.
Or you actually have a ~16" barrel.
It’s definitely a 20" barrel.
Here is everything I’ve measured with the CED M2 since I received it. XM556 from the same lot was reading 2952 fps out of my 14.5" Noveske N4. Does that seem low as well? Unfortunately I don’t have that rifle with me right now to chrono the Black Hills through the 14.5" barrel.
Hmmm… strange. Didn’t see the chrono info above.
No worries, I certainly appreciate your help either way.
