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Posted: 10/30/2006 7:59:24 AM EDT
| I have a Bushmaster M4-gery that has a 16" stepped barell, is this a "mid length" or a "car length". Is this definition barell or gas port dependant? Sorry for the crappy spelling ~lol~h.gif |
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well, i dont believe that bushmaster makes a middy yet, so i'll say its a CAR length that you have the "stepped" part has nothing to do w/ the gas system length; "stepped" could refer to a couple of things, but usually to either: the stepped down portion on an M4 bbl (the cut out) for attaching an M203 or the stepped down cut on the muzzle for a propper crowning got a pic of the bbl? |
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Yeah - "mid-length" refers to the fact that the gas port is at 8.5" down the barrel instead of 6.5" like a CAR or 11.5" like a rifle. www.ar15.com/forums/topic.html?b=3&f=66&t=266108 Any profile barrel could be considered "mid-length" if it had a gas port at 8.5" (HBARs, M4s, lightweight, etc). |
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I am a noob too! Great writeup on the AR operation and gas factors on ejection. Taking a barrel and putting the gas port in different locations would affect the rifle timing, the way I undestand it. I have not bought my upper yet and I am looking at building a tactical build for a first time. Does it matter to me where the gas block sits on a 16 inch barrel at this point? |
| I'd go mid-length just for the lower pressures meaning (most likely) longer bolt life, smoother cycling, and less recoil. The only reason to go CAR-length is to get the wider assortment of accessories that fit them and the (usually) lower prices. In addition, a 16" middy can use a standard M7 or M9 bayonet, and a 16" CAR cannot. The "timing" issue (assuming you mean dwell time and such) is fixed by opening up the gas port wider for less barrel past the gas port. |
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