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Discussion Starter · #1 ·
I pulled out 3 LRB receivers and some barrels and noticed some difference in the fit that, being new to M14 family, led me to some questions. So I thought I would post here as a matter of curiosity and comment.

LRB M25 receiver with USGI barrel as tight as I can get by hand and all the USGI barrels fit this receiver like this:


The same USGI barrel in a LRB M14SE receiver (a fat 1/16") gap:


Here is the same LRB M14SE with a Krieger heavy (It goes all the way to the shoulder)


HOWEVER, the Krieger DOES go down about all the way on the M25 also whereas the USGI barrels did not. I also have the LRB M25 rear lug which threads them down about all the way. So, two LRB receivers behave exactly the same. The third was different in the way you can see. And interesting that the 3 USGI barrels where consistent with the way they fit the receivers above and were noticeably different than the Krieger.
 

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Top pic, check for burrs or a small dent on the barrel threads.

Second pic, a gap is not always a bad thing. I just did some experiments with G.I. barrels and found that since the inner shoulder only contacts the barrel ring a very small amount ( removing one , you will see this) then I sumised that the outer shoulder contact might be heating up and causing grouping issues. I rolled the outer edge of the shoulder on one that was grouping irratically, and left a gap, while keeping full contact inside and indexed properly. The horizontal stringing went away on this particular rifle. I changed nothing else about it, so I can only assume, the outer full contact of the shoulder was causing it, after swelling up from heat, or that the outer contact was not completely perpindicular to the bore, and hitting along the area unevenly. Once torqued in, I can't see it going anywhere....Also in pic two, that might have been a running take off, and has already been rolled back to index.

Has anyone else seen this before or tried it ?
 

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Barrel fit

A few years ago, LRB had some minor problems with barrel fit due to the method of heat treating being used. It caused tight fit, but the barrels could still be screwed in and indexed with the proper tools. After determining the problem's cause, the heat treating operation was modified and the problem disappeared. Very few receivers were effected. Please don't infer that there was any discrepancy in the actual heat treating, there wasn't. It simply had to do with the way the receivers were positioned in the rack while being treated.
 

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Discussion Starter · #5 ·
I did contact LRB and described the issue in detail. They felt it would not impede proper barrel fitting or affect the receiver in any way. The made note of the receiver serial and stated that if it was an issue at the time of the build whenever it may be, they would stand behind it. That definitely gives be comfort. But it sure freaked me out when I tried those barrels to see the difference among the receivers.
 

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Top pic, check for burrs or a small dent on the barrel threads.

Second pic, a gap is not always a bad thing. I just did some experiments with G.I. barrels and found that since the inner shoulder only contacts the barrel ring a very small amount ( removing one , you will see this) then I surmised that the outer shoulder contact might be heating up and causing grouping issues. I rolled the outer edge of the shoulder on one that was grouping irratically, and left a gap, while keeping full contact inside and indexed properly. The horizontal stringing went away on this particular rifle. I changed nothing else about it, so I can only assume, the outer full contact of the shoulder was causing it, after swelling up from heat, or that the outer contact was not completely perpindicular to the bore, and hitting along the area unevenly. Once torqued in, I can't see it going anywhere....Also in pic two, that might have been a running take off, and has already been rolled back to index.

Has anyone else seen this before or tried it ?
surmised - there, I fixed it !
 

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Ohh yeah, I forgot...Andy has seen this first hand at my house, ...I told him and showed him first about the barrel binding on that rifle that I put a gap on.....thanks for the spelling correction...I was rushing to quick buddy
 
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