I am going to put together a short upper with a heavy SS barrel with a FF forend. It will be for precision shooting.

 I am having trouble deciding between a 16 barrel with a carbine length gas system or an 18 with a mid length. The 16 is definitely easier to find.

What are the advantages of a mid length gas system and do they outweigh the easily located barrel with the carbine length gas system?

 I would appreciate any input you have.

well... neither choice would be as good as a 16" with a midlength gas system.

Mid length is becoming common. 16" midlengths are awesome.

please suggest some barrels

for what you are doing, hit up Steve at ADCO...

Quoted: well... neither choice would be as good as a 16" with a midlength gas system.

Originally Posted By Combat_Jack 16" midlengths are awesome.

I'm new to the forum and AR'15's, have got the black rifle fever prety bad and am seriously considering a RRA 16" Varmint.

Are you guys joking about a midlength gas system on a 16" barrel?  Would the gas port be past the end of the barrel?

If not joking, could someone please explain why a midlength gas system is so awesome with a 16" barrel?

Thanks
firstshot
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Make your first shot count!

Midlength gas systems reduce the pressure the operating components are exposed to, lengthen the recoil impulse resulting in a softer shooting weapon, and are generally better. A midlength gas port is located only 2 inches farther down the barrel than a carbine gas port.

Combat_Jack

Thanks a bunch for the clarification.  As far as production rifles are concerned, at what point of barrel length do the the mfgs normally start using the midlength gas system?  Would the midlength gas system normally be used on a 16" or 18" barrel, or is this type reserved for the 20" & 24" barrels?

I'm looking at a RRA 16" or 18" Varmint.  Would this model come with a midlength gas system or is it something I would have to special order?

Thanks
firstshot
-----------------------------------
Make your first shot count!

M&A Parts sells a couple of mid length uppers that are 16". Their mid lengths use RRA uppers for their builds.

Gordon

First, I am not an "expert" on this issue, though I did stay at a Holiday Inn, once.

Barrel length and gas system length are two different things.  It is theoretically possible to put a short (carbine) length gas system on a 24'' barrel.  While a rifle or mid-length gas system can't be used on the real "shorties" 14.5" and under barrels (they can but special mods are required).  

The mfgs of mid's have 16" barrel setups that use a short or mid-length gas system.  There are some that even use, as I understand it, a rifle length system on a 16" and it is called a "Dissipator" (I'm not real sure on that part).  The natural progression is that barrels any longer than 16" and under 18/20" usually get one of the longer gas systems and barrels over 18" usually get the rifle system. I believe that's the way it works in most cases.  Others will chime in and correct me, for sure.

Basically, the mid-length or rifle length gas systems perfom better with less system stresses than the short systems.