Have a question on the McFarland rings. I’ve installed McFarland rings on several Colt M4A1’s and without fail, the rings provide little to no tension inside the bolt carrier. After installation, the bolt will readily collapse inside the carrier if the carrier is inverted. Thus, I’ve been unable to use them and have had to replace worn rings with the three-piece arrangement. For what it’s worth, the bolts have seen anywhere from 3500-7500 rounds down the barrel. Do any of y’all know if this is something particular to the M4A1?
I don’t have much experience with mcfarland gas rings I do have a set but I have not installed it yet.
From info on other threads most people say the rings are super tight once installed.
Dont know why yours would be the complete opposite:confused:
I’ve heard from others who use them that they provide plenty of tension. Some think they’re the cat’s ass as far as bolt/gas rings go. That’s just not been my experience with them on the M4A1. Just wondering if anyone else has noticed this issue. Appreciate the reply.
It’s not just one bolt carrier. It’s several. Different bolt carriers, different one-piece gas rings, same result. Little to no tension. That’s what’s so strange. I can’t imagine there is that much variance in the I.D. of a batch of bolt carriers. I’m at a loss to explain it…
Bad Mcfarland rings. Try another set something is not in spec with those.
There has been a few reports in the past of imitation mcfarland rings:confused:
Whats the O.D of one of the new uninstalled Mcfarland rings you have?
Dealing with a battery issue on the caliper,but the one’s I have from Midway/DPMS are reading .5020".
Been using the Mcfarlands for almost two years and Ive not seen a quality one fit loose by any means of the word.
That said,as Thomas M4 mentioned.I did run into some cheap knock offs sometime back that were like a buck fifty or so.They were made by a company that is no longer in business and marketed under a Armalite part number.I can’t remember the specifics but I posted about it in a thread here at the time.
Being curious,I purchased some and the cheap rings,and they varied greatly in fit,some kinda loose and most extremely tight in the carrier bore.The thickness of the rings varied as well and fit extremely tight in the ring groove of some bolts I have.Which IMHO would cause the bolt to bind in the carrier as the ring compressed.
HTH
ETA
Call Grant @ G&R Tactical if you need some Mcfarland rings…I know he has the good one’s as thats what Im running in my LMT BCG’s.
Left my calipers at work, so I’ll have to wait til Monday to measure the O.D. on those rings. Hadn’t thought to do that before, but I’m assuming they’ll measure a little shorter than .5020".
Meanwhile, I’ll order of few more sets from G&R and see if they fit better.
Ive had a few mcfarland rings sitting around for a couple years…just put one in a new BCM BCG I had lying around, and the bolt is very tight in the carrier…as in very hard to push it back in the carrier, and pull it out.
This is a very timely thread since I just replaced the rings on my RRA BCG with the same Brownell’s Macfarland gas rings and noticed the same exact loose fit. They fit a little tighter than the old ones but still not that tight compared to my BCM BCG’s. Does anybody know what the inside diameter of the carrier is suppose to be?? I was thinking about upgrading this BCG with another BCM but now this seals the deal…
Not sure what the “spec” I.D. is off the top of my head, but I’ll measure a few Colt carrier I.D.s on Monday and let you know.
Just out of curiosity, if you still have the one-piece rings installed on your bolt, does the bolt collapse inside the carrier when the carrier is inverted? That’s how loose those rings are in the M4A1 carriers I posted about. Wondering if they act the same in an RRA carrier…
The carrier collapses very easily around the bolt. The gun has always felt under-gassed and thought these new rings would help but apparently the carrier is out of spec…The rings all measure the .503 previously posted. I did shoot it with the new rings and it did seem to perform better…