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Discussion Starter #1 (Edited)
AR barrel in the ACR, and what comes in the box?

So I really hope this isn't a uber newb question but, is the ACR barrel a standard M4 or maybe a mid length barrel? As in one can just swap barrels with a little machine work of course for the piston guide but aside from the ratchet part that locks into the trunnion are they the same?

James

P.S. Yes I updated this, does the basic model come with sights? And what's this I sometimes see about a hard case? What kind of accessories come with a NIB ACR?
 

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Short answer is no. Gas port is smaller on the ACR. Long answer is that a couple people have made them work and made them work well, particularly in SBR form. Need to port over your stock gas system or get another set.
 

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you can check out the thread in my signature for a general idea of what i had to do, uxi is correct, the gas port is the hardest part to get right for the acr, the re-profile job isnt that bad

short answer you can run a ar15 barrel but it will need some mods to work
 

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What if you got a H/L gas regulator instead of a S/U regulator?
Could you fake it by using the H setting?

IDK, just throwing ideas out there.
 

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Problem is too much gas since the hole for AR's is too big.

bigdog2003's thread is exactly one of the guys I'm thinking of. If Spikes was still putting out barrels, I'd probably order one. Keep hoping Noveske would do at least a limited run of light profile 1/7 14.5" barrels with the correct gas port size.
 

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no because the gas port is way too large, when i did my 10.5" conversion i could cycle my rifle on the s setting, and it was still overgassed

heres an example for a 10.5" rifle
ar15=.091 (approx and varies between manufactures)
acr=.063 (again approx)

you could have a company like adco reduce the size of the gas port when they reprofile it for the piston rod support, but i dont know the proper size
 

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What symptoms were you seeing from being overgassed, bigdog? Strange ejections or dented cases and the like? Any FTF or FTE? What would be the short and long term concerns of running overgassed?
 

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my rifle was cycling on the s setting without a suppressor, it would sometimes not the trigger properly and have slam fires, sometimes after a slam fire it wouldnt have the trigger cocked, it would also double feed sometimes-this all happened multiple times in 20 rounds

the sporadic ejections and dented casings could be a sign too but i'm not sure, i think the dented casings could also be a sign of a feed ramp issue (my new acr does this)

running slightly overgassed is ok, if its not too much-the hk 416 is actually designed to be overgassed to help cycle it in adverse conditions (it only has 1 gas port setting on most models)
 

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Discussion Starter #9
Thank you all for the reply's, here's another one, are all current ACR barrel's 1:9? Is everyone still waiting on the 1:7 to be released? I'm trying to decide on my next purchase as I'm waiting on my stamp for my LE6921 and have a bunch of 77gr rounds for it and if I remember correctly they won't stabilize out of a 1:9?

James
 

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some people have been having good luck with 75gr on the acr, a couple of people have measured their barrel twist and they got 1:8, so you might be in luck
 
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