[NavyWings]

I'd like to know if anyone has run any accuracy comparisons between 5.56 and .223 in the ACR. It's my understanding the ACR is chambered for 5.56. This is conservative and safer in allowing both .223 and 5.56 (most late model AR-15s are chambered this way as well) vice a .223 chambering where using a 5.56 round could cause excessive wear and possible safety issues (due to the shorter leade length).

I've been shooting .223 in mine and have put about 2000 rounds through it. In theory, I believe 5.56 should be more accurate but haven't seen any accuracy comparisons. Thanks.

 

[Tommys229]

why do you think it should be more accurate?

 

[oif0709]

I think the 5.56 had a bit more of a charge in it. As well as different headspace. I think the accuracy may come to the load itself. I havnt really seen acuracy loaded 5.56 but the. 223 there is lots for. My target ar is chambered in.223 and its not reccomended 5.56 is used. But a 5.56 can shoot .223. I personally use 69 grain matchkings by sierra with varget powder. I got the acr actually because I have such a large amount of 5.56 that I can't use. Its not very accurate stuff. I havnt seen 5.56 ammo groups nearly as nice as some of the better commercial stuff. Pmc I have had good luck with.

 

[DSM]

I havnt seen 5.56 ammo groups nearly as nice as some of the better commercial stuff.

Find yourself some Mk262 and you'll see a 5.56 load that'll cut x-rings all day long.

But true, most 5.56"loads are service ball. M193 has an acceptance of 4MOA if memory serves me correct, that's usable but nothing to write home about. The "mil-spec" stuff comes mostly from how the round is loaded, i.e. properly annealed cases, waterproofed, etc. They're tested randomly for velocity variations and accuracy among other things.

Talking with a lot of industry folks throughout the years most of them have altered their chambers to allow either/or, regardless of what the barrel is marked (in regards to mass produced barrels, custom tubes are another story of course.) Their reasoning, and rightfully so, is that changing their dimensions costs a whole lot less than the cost of lawyers when Jethro drops in a cheap, fun show, surplus round, no matter how many warnings they put in the manual. Of course better safe than sorry.

 

[oif0709]

Exactly. Plus the major buyers and users of 5.56 are more or less putting alot of bullets through the air rather than trying to get sub mow groups. I will deffinatly have to look into that mk262 though. Thanks.