Comments on: Tech Tip: Fit One-Piece McFarland™ Gas Rings in Your AR

By: Chris W

Chris W — Fri, 18 Dec 2015 21:22:05 +0000

My pistol 7.5″ barrel upper continually seems to realign all three gas rings so that gaps align. After even just one magazine! Then the empty brass fails to eject and I have a double feed. I can’t wait to try this one piece.

By: Fred

Fred — Thu, 23 Sep 2010 22:28:55 +0000

Dom you have to peel the edge of the one piece off and guide it into the channel and then rotate it around and around while keeping pressure on the ring it will wind right into the channel.

I have a failzero bolt and this one piece design is very very tight and has me a bit concerned about firing it like this.

By: Dom

Dom — Wed, 02 Jun 2010 17:27:33 +0000

How do you install the 1 piece gas ring?

By: Editor

Editor — Tue, 11 May 2010 18:43:35 +0000

Steve,
Thanks for the feedback. I have seen the split rings cause a problem in 16″ barreled rifles shooting milsurp ammo with sustained rapid fire (meaning multiple 20-rd or 30-rd magazines shot quickly.)

Obviously, however, if the mil-spec rings work 100% for your use, one-piece rings may not be advantageous.

By: Steve R.

Steve R. — Tue, 11 May 2010 16:40:29 +0000

Firing tens of thousands of rounds in High Power comp, using several different uppers, not one alibi using the mil-spec, 3 piece, gas rings. I don’t pay any special attention to the gap alignment when cleaning/reassembling.

By: puppezed

puppezed — Mon, 10 May 2010 14:25:02 +0000

>With conventional gas rings, you need to correctly rotate each ring so the “gap” does not line up, thereby allowing gas blow-by that can cause cycling problems.

I wonder how this legend this lives I´ve never ever heard of anyone with gas ring alignment problem IF the rings have been intact.

A friend of mine bought a new custom AR with regular bolt with McFarland rings + JP lightened steel carrier. The gun did not cycle properly. After replacing McFarland rings with regular rings the gun worked ok. Dunno what was wrong with those rings.

By: f d shuster

f d shuster — Mon, 10 May 2010 02:13:53 +0000

My experience with the McFarlands mirror’s that of the editor. My Colt H-Bar upper, bought new in 1995, and now on it’s third barrel, (original Colt, and 2 Kriegers), 10,135 documented rounds fired, same Mcfarland ring, since 1997. Use nothing but Breakfree. Two Bushmaster upper’s each with 5 & 7800 rds. fired, same McFarland rings.

By: Editor

Editor — Sun, 09 May 2010 23:34:50 +0000

Aha… we may have something. The Young National Match bolt carriers are chrome-plated (at least as shown on http://www.youngmanufacturing.net). It is certainly possible that the McFarland ring might behave differently in a hard-chrome-plated carrier which may have tighter tolerances and different surface properties. That’s worth noting.

I am reminded of the fact that way back in the early days of the M16, the government specified chrome-plated bolt carriers, then abandoned the idea because the chrome carriers wore out the uppers at an accelerated rate. Here’s one comment: “External chroming on your carrier is both unnecessary, and detrimental to life of your upper receiver. Strips thru/wears dry film lube, breaks thru residual CLP. Uncle Sugar found accelerated wear patterns in uppers in the mid 1960s and pulled the chromed carriers for these reasons.”

By: B re25

B re25 — Sun, 09 May 2010 19:13:44 +0000

Both were Young national match bolt carriers, spoke to Dan Young about it and he confirmed I was not the only one. Yes they were properly lubed

By: Editor

Editor — Sun, 09 May 2010 05:18:06 +0000

to Bre25–
My experience, with 4 different AR uppers using one-piece gas rings, is 100% opposite to yours. The one-piece rings worked perfect and there have been no wear issues after literally thousands of rounds.

I do apply a heat-resistant lube through the bolt-carrier hole and I keep my bolts very clean and remove excess carbon build-up inside the bolt body.

It has also been suggested that wear can be accelerated if the bolts or carriers are slightly off specs. My uppers all use genuine Colt bolts and bolt carriers.

Otherwise there is really no reason why the one-piece rings should wear faster than conventional AR bolt gas rings. If anything, they should last longer — and that seems to be the experience of most users.