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Discussion Starter #1
This may sound stupid, but bear with me.
I've been shooting my 3 Mosin-Nagants for the past year 2-3000 rounds. Primarily with Bulgarian HB and Russian surplus. I've never had a case split or anything except for 1 in 200 primer blowback with the Bulgarian.

Now I've become aware and obsessed with checking my headspace. I bought a No-Go gauge and it failed in 2 of the 3 rifles. Now I'm mailing for a coin type field gauge from Yankee Engineering.

I'm just wondering how many of you bothered to check headspace and how many of you trashed your rifles because of headspace? Or how many correct headspace in any manner?

Thanks.
 

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Mr. Flashy Pants
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I didn't bother at first, but when I began to focus on Mosins and learned more about them I bought a set of gauges and check them now. Not that I'm any more worried about them, but gauges are cheap and it's easy to do. I've never bought a Field gauge, but now that I understand them better that's what I recommend. Before I really knew better I had a rifle that would not pass a No-Go gauge and could not be corrected at all. It was nothing special so I chopped the receiver and stripped it for parts. Now I wonder if it would have passed a Field gauge. Every other rifle I've not had any trouble correcting the headspace, to No-Go specs no less, by changing bolt heads.
 

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I have several sets of headspace gauges in various milsurp calibers. The only ones that ever get used are the "Field" gauges.

Liberty
 

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Discussion Starter #5
Thanks for the input.

The thing that I hate about the headspace obsession is that the fired brass is fine, no bulging with a minor amount of shoulder expansion. My friend down the road has a Remington
hunting rifle (1960's used only for deer season in that decade) with more case expansion than my Mosin (1936). Also fitting a new bullet in his fired brass is loose in the neck, mine is a nice snug without being tight, so it must be sealing nicely in the chamber.

Thanks again, I'll try a bolt head and see what happens to satisfy the gauge.
 

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I have a Yankee Engineers No -Go gauge and I have only had one rifle that failed. I was unable to correct the problem even with changing the bolt head.
 

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I use the Yankee field and never a problem. Before getting it, used a 1/2" plywood 2x2' sheet held low over the receiver and heavy gloves while another pulled a trigger string for first shot. The Yankee is a much better process.

Either way, I inspect the first several cases very well to look for potential problems. I nver mix "new" ammo with a new rifle, but shoot ammo from a lot that I know is tried and true.

I note your one primer bust was Bulgarian Heavy Ball. I and others have recently received Bulgie LB with '52 or '53 year that was in less than great condition, but have heard no problems with the heavy ball. Do you recall the year?
 

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Discussion Starter #8 (Edited)
I use the Yankee field and never a problem. Before getting it, used a 1/2" plywood 2x2' sheet held low over the receiver and heavy gloves while another pulled a trigger string for first shot. The Yankee is a much better process.

Either way, I inspect the first several cases very well to look for potential problems. I nver mix "new" ammo with a new rifle, but shoot ammo from a lot that I know is tried and true.

I note your one primer bust was Bulgarian Heavy Ball. I and others have recently received Bulgie LB with '52 or '53 year that was in less than great condition, but have heard no problems with the heavy ball. Do you recall the year?
It was 1954. But with that same ammo I was able to shoot 1/2 dollar groups @ 100 yards. Either that or I just had a good day. I love that HB.

I'm trying to remember if that last round with primer blowback was the first shot I took after a barrel swab? Pressure? Also if you mate a live round bullet head into the burstprimer spent case it was very tight, too tight. The only one like that. I guess the case didn't expand properly.

I grew up with Garands. Never such a problem, with anything.
 

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I got a Yankee Eng. field gauge last week and checked 22 Mosins. All passed, had to adjust just one firing pin. Now to go shooting.
 

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It will take from 2 to 3 weeks to get the gauge from Yankee Eng. as they don't make it until they get the order. It's well worth the wait.
 

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The ONE that I rely on for an assembled, used weapon is the "field" gage from Yankee. Be sure and specify "milspec" (military specification) and NOT "SAAMI" (Sporting Arms and Ammunition Manufacturers Institute - commercial manufacturing standards)!

My Mosin collection is less than 200 pieces and I have a few with excessively worn and rotten bores and some of those have mismatched bolts. My life is not filled with good luck, so I am considering it "average" that I haven't had to make any bolt head swaps to achieve proper headspace.

I offer this information along with a neat graphic to better explain headspace with a rimmed cartridge. The .303 British is close enough to a 7.62x54R for a legitimate comparison.

http://p102.ezboard.com/fparallaxscurioandrelicfirearmsforumsfrm49.showMessage?topicID=7075.topic
 

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Very overblown issue and really only a problem in very high pressure rounds. In my experience moderate pressure cartridges and especially rimmed cartridges, and the 7.62 Russian is both, can have excessive headspace, well beyond the field limits, the case can get ripped in 2, yet you'll just get a puff of smoke out of the rifle. The stretched edge of the case, plus the rim, seem to seal most of it in. Only real problem is prying the stuck front of the case out.

Take a look at the Turk 1893's as an extreme case. I've found 15% of the Turk 1893's I've checked had excessive headspace on the field guage. They were made for a 45,000 cup round, have virtually no gas shielding, converted to the 49,600 cup 8x57JS round, (which is rimless, too) and I'd guess most of the Turk surplus ammo is way hotter than that, yet no reports of injury or rifle damage from shooting that combination. I headspace them and download the turk ammo 25% to avoid any unpleasantness, the stuck case problem, and long term wear but I'm sure plenty with excess headspace were shot with the standard turk ammo and no reports of injury.

So far every cause of a badly stuck bolt and/or rifle damage I've seen has been an overload, and where I could trace the ammunition used, it was a reloaded round of doubtful provenance.
 

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The Yankees are great since you dont have to remove the extractor from the bolt head to use them. I have the "Go" "No-Go" and "Field" in 7.62x54R- I guess I just like to know where I'm at....Well worth the investment.
 

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In my experience with collecting reloading for and shooting Mosins since 1989, I've only had a few MN rifles fail a SAAMI field gauge; in most of those instances, I was able to restore them to shooting condition with different bolt heads swapped out of my massive spare parts box.
The rifles with the excessive headspace were primarily Remingtons; only one appeared to be very well-used. Also, one M28 had excessive hs and couldn't be corrected.
All of the rifles I've fired with excessive hs--even the ones that turned out to fail just the SAAMI no-go gauge--inevitably had a locked-up bolt that had to be forced open after firing with surplus or commercial ammo. Any locked up bolt on a MN after firing normal ammo is a signal to check the hs.
Even fire-forming the cases and only neck sizing afterwards produce similar results. (not lower pressure cast loads, though)

Now, the ideal solution, one that wouldnt require a barrel reset and rechamber--which would ruin a collectible--would be to have new-made bolt heads of different lengths--what I mean by that is greater distance than normal tolerances between the front face of the bolt head and the rear faces of the locking lugs. With say, three different sizes, almost all hs issues could be resolved easily. The British did this with the #4 rifle, but it was easy as the locking lugs were not on the bolt head itself. The #4 excess headspace is easily correctible by exchanging the bolt heads.
Too bad Sergei didn't think of this solution.

OTOH, I have enough MN now that I simply don't shoot the few with excessive hs. Why bother?
 
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