Ar Gas system length

Remingtonman

New member
Getting ready to put together another Ar upper in 223 wylde and was wondering about gas length for the upper. Is carbine, midlength or rifle length best for a 16" barrel? If my understanding is correct the shorter the gas system length the more recoil I will get?
 
I prefer mid length for 14.5" up to 20". I have a rifle length gas on my 20"
 
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using a mid length gas system can also help ease the lock time issues many 16" carbine (over) gassed systems face and help lower the abuse your brass can show with many factory loads.
 
I'm going to jump on the mid-length bandwagon. Most of the 16" barrels we sell for custom builds are midlength gas. There are a ton of carbine length uppers and rifles out there that work just fine, but most would prefer midlength if they had a choice.
 
Mid-length gas ports are perfect for 16" barrels. My next 16" build will have one for sure. I bought my first carbine before they started putting middy gas systems on them, and I've been thinking about trading that upper for one that has it.
 
My 18" long barrel from Ambush Firearms (Daniel Defenses Hunting Division) uses a mid length gas tube. I'm not sure what type of spring they put in the buffer or how heavy the buffer tube is. I hear that the weight of the buffer tube also effects the cycling and timing and the amount of kick back.

I let the X-perts at Daniel Defense build my AR-15 for me.

I read that one can tell if the gun is setup right if the shells kick out of the chamber in the right direction. Back somewhat from directly straight out of the ejection port. If they empty shells go forward or too far to the rear then the setup is not right. My 5.56 M885 shells kick out at about 3:30 Position where the muzzle would be the 12 O'clock noon position.

I think that DD calls it a mid length tube system with the low profile gas block on it. The Bolt Carrier group is standard Mil Spec IIRC.
 
I'll represent the dissenting opinion and recommend using the length shorter than common for a given barrel length, combined with an adjustable gas block. You can always throttle a carbine length to behave like a mid-length, but it's difficult to ask for more gas if you ever find you don't have enough. For 20" and longer, I run rifle length, but for 16" I run carbine, for 18" a mid-length. If going to run suppressed, then a guy can move out a size, in general, but an adjustable gas block really is the way to go in my book.
 
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