Bulged Barrel Replacement--Barrel Extension Question, Etc.
Some time ago I posted about a possible bulged/ringed barrel, apparently from firing a CMMG unit and an obstruction that escaped my notice. A gunsmith who has seen a lot more of these than I have (none, up to now!) made the call and although there's not much to see, the tight/loose/tight patch down the bore pretty well tells the story.
I will probably pull the M4 type barrel and replace it with a pencil type myself. I have rebarrelled a couple of Garands without problems, and already have have headspace gauges for .5.56. Don't have the AR wrenches or clamping blocks but figure the usual approach of read the book, calculate twice, measure twice, go slow, should work out and I will have the satisfaction of doing it myself at about the same overall cost--and still have the tools.
I do have a question, though. Even with reviewing the USMC 16A2 manual and Kulek's books, I am a little hazy about whether the barrel extension comes as an integral part of a replacement barrel, if I am to use my take-off, or what. Also, what the matchup for M4/not M4 feed ramps might be. No doubt it's dirt simple once I see it, but I can't quite get my head around it with the manuals I'm using. :confused:If anyone can enlighten me I'd appreciate it.
The rifle currently has about 3400 rounds of 5.56 through it. I am thinking of replacing the bolt assembly and cam pin on principle at this time, so as to mate up a new bolt to the new barrel and wear these surfaces in all together.
Don't know what the moral of all this is other than be careful of possible squib rounds when using a .22 in rapid fire. I suspect that might have been the case and I got distracted when clearing a FTE. And I even checked the bore anytime I had a suspicion! At any rate, the conversion unit turned out to be an expensive option for low cost shooting. It may well be replaced by a 15-22 for practice.
Ideas or comments solicited. Thanks.