Bolt to receiver fit on Norc M14

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SVKB

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Hey guys,

I did some searching and couldn't find exactly what I'm looking for so forgive me if this has been asked before. I'm very new to the M14 scene and I'm trying to educate myself as much as possible. I've read a pdf regarding the bolt to receiver fit, specifically issues with the left lug. The pdf gave instructions on how to check it to make sure it's fitted properly, but I'm still a bit confused.

Does anybody know of a video (or have pictures) on how to check this. Maybe detailed instructions on how to check and what to look for. I don't think I have an issue, but I want to make sure.

Thanks

Edited: This is the link to the pdf I was reading

www.m14.ca/seminar/M14_Seminar_EBR.pdf
 
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So I did some of the measurement that he pointed out in the second video. In the one example that he did, he measured the bolt to receiver fit with a set of feeler gauges. In the rifle he measured he noted that the fit was exceptionally tight at 0.004". I have significantly more than that. My question is how much play is too much?
 
SVKB said:
So I did some of the measurement that he pointed out in the second video. In the one example that he did, he measured the bolt to receiver fit with a set of feeler gauges. In the rifle he measured he noted that the fit was exceptionally tight at 0.004". I have significantly more than that. My question is how much play is too much?
Click to expand...

Good question. I have two that are both over .010" (worst one is .014 over) over the go gauge and they don't blow cases and the brass can be resized and shot again. If you are reloading, the process of having the brass fireformed to a longer chamber, then resizing back the shoulder on the brass works and stresses the brass more than a tight chamber and minimal resizing. It shortens the life of the brass. How much? I don't know, but I have had no problem so far with reloading it once or twice.
 
Grizzlypeg said:
Good question. I have two that are both over .010" (worst one is .014 over) over the go gauge and they don't blow cases and the brass can be resized and shot again. If you are reloading, the process of having the brass fireformed to a longer chamber, then resizing back the shoulder on the brass works and stresses the brass more than a tight chamber and minimal resizing. It shortens the life of the brass. How much? I don't know, but I have had no problem so far with reloading it once or twice.
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Hey Grizzlypeg, thanks for the response. I'm only 2 hours west of you!

I didn't measure headspace, (I don't have the appropriate tools) but I measured the distance between the right lug and the receiver when the bolt is fully closed. I could fully close the bolt with a 0.020" feeler gauge between the right lug and receiver.

It seems to shoot fine with no deformation of the cases that I can see (that's commercial .308 as well) but I've only put 60 rounds through it thus far. I haven't even got it 100% zeroed yet (long story).

I don't do any reloading... yet. It is something that I want to get into eventually.
 
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I'm not sure your measurement would be that meaningful. With a go gauge in the chamber, the bolt is pushed rearward, closing up some of that gap. With no gauge in the chamber, the bolt can move forward further and the gap will be larger. It's how far rearward it can go from closing on a go gauge that would approximate excess headspace. Also, I disassembled my bolts so that the ejector wasn't pressing against the go gauge.
 
Grizzlypeg said:
I'm not sure your measurement would be that meaningful. With a go gauge in the chamber, the bolt is pushed rearward, closing up some of that gap. With no gauge in the chamber, the bolt can move forward further and the gap will be larger. It's how far rearward it can go from closing on a go gauge that would approximate excess headspace. Also, I disassembled my bolts so that the ejector wasn't pressing against the go gauge.
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That's what I was wondering, but I was only following what he did in the seminar video. I've got a local gunsmith in town who said he through some gauges in it to check headspace. Guess I'll wait and see what those come in at.
 
I'm not sure myself on that, as I defer to Hungry's vast knowledge. Me, I also verified it by stacking scotch tape over the end of the go gauge and measuring the thickness to close up the gap. Came quite close to the feeler gauge at the lug method.
 
Do not follow Lary's guide to lapping a bolt. Anyone in there right mind will tell you that you should never modify a chamber gauge and you should also always ensure that the extractor and ejector should be removed before lapping. As lapping compound tend to creep in every were and I would not want that stuff in my bolt.
But hell what do I know?
 
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