Head spacing a Mosin Nagant after fixing a broken bolt

You BROKE the bolt on a Mosin? (too many questions here)

A whole 'nuther rifle is less than 100 dollars.

I'd go that route, if I was me....
 
How did you manage to break a bolt? ive never heard of the bolt breaking on any gun. I also have never heard of a mosin nagant breaking. I'm not saying it didn't happen because obviously it did, I just want to know how:D
 
Nice video but full of misinformation. The headspace gauges are good and should be used when purchasing an old military rifle such as the MN. The two important gauges are the go and the no go. The go lets you know that there is enough headspace and the no go lets you know if there is too much headspace.
Some people use a field gauge, but it indicates Maximum allowable headspace. Most gunsmiths do not use the field gauge.

Because of the design of the MN bolt, the part you replaced does not effect headspace. If you had to replace the head of the bolt (the part that contains the locking lugs and the bolt face) then you have to recheck headspace.

Other bolts like the mauser do not have a removable front section so if it is replaced, then the headspace must be checked and usually requires a gunsmith to re headspace your rifle.
 
And it's my understanding the headspacing should be checked with the extractor removed.
Denis
 
They do have the cutout, I was just mentioning I've heard it from two different sources that deal with Mosins regularly. :)
Denis
 
They do have the cutout, I was just mentioning I've heard it from two different sources that deal with Mosins regularly.
Denis
Click to expand...

Purpose of the cutout is solely to avoid having to remove the extractor, which can be a PITA and easily bent.

I didn't watch the video, but SC is correct.

I had a Mosin fail a no-go gauge test (some say it never happens...), and was able to swap out the bolthead with a bit "thicker" one to solve the problem.

I, too, am not a fan of the field gauge. They indicate marginal headspace, which will only deteriorate with time. CMP standards do not allow for field gauges. If it closes on a no-go, swap boltheads until you find one the shortens the headspace enough. Go gauges are usually only used by a smith when re-barreling.
 
Please, Don't take this the wrong way, I know that videos can be deceiving, but if I am seeing this as I think I am, you may be able to tighten up your groups a bit if you stop jerking the trigger.

Pull it through the creep and then squeeze until you hear a bang.

I'll say it again, I could be wrong but I'm just tryin' to be helpful.
 
Take a dozen Mosin Nagant bolt heads. Put them on a granite surface plate. Use a height gauge.
Measure from the back of the lugs to the breech face.
They are all the same.

Take a look at the extractor relief cut.
It is 90 degrees plus twice the width of the extractor.
That is almost 180 degrees, but not quite.
That means the rim is supported for more than 180 degrees to stand up against the firing pin.

There may be some variations is barrel and receiver thread clocking, but what are you going to do about it?

Are you going to set the barrel back a thread?
I have done that, but I don't think you are going to.

I have made a headspace gauge for Mosin Nagant, with the extractor on the bolt head. I use this for barrels from scratch.
 

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  • 7.62x54R headspace gauge drawing and pics 6-23-2011.jpg
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I'll have to respectfully disagree with your opinion that there can be no "wear" on the rear of the locking lugs of these 100 year old rifles...
But with that said, what is the purpose of the 10 degree angle on the gauge, when the boltface itself, is flat?
 
mauser bolts

hello new to the forum,my question is is it possible to use Spanish mauser bolts in a sweedish 96 action just curious thanks
 
you dont know if the original bolts headspace sooooo

how often do you find a bad one and how bad before s]its a real problem for low rounf
ds

even a bit off is not going to blow (or so I think 0
 
I had my Mosin rebarreled and at first it was fine, now the bolt is next to impossible to open after firing a round.

The go gauge fits, the field and no/go will not fit.

Seems like too little headspacing in my case. :(
 
Get it to a gun smith.

That is good. He can ream it out and have you good if thats the issue

Or find out what is.
 
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