Mosin Headspace Problem

[bohoki]

they are tough guns i think the worst that will happen is you will notice split necks

[Patric78]

Thank you. Glad to be here, especially to ensure folks get what they deserve, and to enrich the community whenever possible. ��

[sdfire]

you should be concerned about the firing pin depth. Make sue the new bikt head allows fir firing pin clearance.

[Hundids]

Fwiw, I use Okie Headspace gauges, as do many collectors whose experience dwarfs mine. They are built with a notch for the extractor, so you don't have to do anything but slip em in and close the bolt. Highly regarded in many collector communities.

I posted on another forum, asking about gauge thickness, and the owner of Okie Gauges piped right in with these numbers, which I thought was a pretty cool move (I assume he won't mind me re posting)


Field gauge 0.076"
NoGo gauge 0.073"
Go gauge 0.064"
Gauge diameter 0.562"
Firing pin clearance 11/64"
Extractor notch 1/4" x 0.180"

I hold my thickness dimensions to +/- 0.0005"



I suppose you could measure the gauge you bought to see if it is close to these numbers.

I have heard many discussions on the fact that there is definate variance across different companies' go, no-go, and field gauge thicknesses - that you should not mix sets because of "stacking tolerances". (Not sure what exactly that's supposed to mean, but I've heard it a few times).

I have buddies who have never checked headspace on their Mosins- ever!
These are the sometimes the same guys who chuckle when gasses spray them in the face.
Me, I've always been a bit more conservative.

Thanks for that piece of information, it's extremely helpful.

Hello Hundids, this is Patrick, uofmdaddy78, I am the maker of the gauge you are using. My good friend advised me of the issue you are having. I'd like to firstly remind you that when you bought my gauge, you also received my word that I would gladly stand behind the craftsmanship of the gauge as well, I'd like to offer you a Field Gauge, free of charge, but I would like to get a hands on of this suspect gauge. If you would kindly go to your eBay account and send me a message with your address I'll gladly send another NOGO and FIELD. Along with a self addressed stamped envelope for the return of the one you have.

As far as the gauge is concerned. Manufacturing errors can happen, though extremely rare, the likelihood of the gauge being off more than .002 in any spot is a long shot. However if an error was made I'll gladly report back asap that finding.

As far as the mosin is concerned, new looking from the crate does not mean properly assembled with parts that pass a headspace check. Very rare, but at least six separate occasions in the 1000+ sets I've sold, have customers found a fresh from the crate 9130 or m39 with too little or excessive headspace.... All were remedied with bolt head swaps with guns they already had. One fellow had three heads swapping back and forth until all were between GO and NOGO.
With that unfortunately mosin bolt heads are not numbered like the 303 bolt heads are... So you are literally playing a crap shoot to find a bolt head that is in tolerance, especially if there's another issue, possibly in the locking lugs or chamber lip.

I sincerely hope to help you get to the very bottom of your issue on this gun, even if proven to be my error.
I surely appreciate the opportunity to make good on the guarantee of craftsmanship that I afforded you when you purchased my gauge.

Stay safe and Thank You!
-Patrick

What a small world. Thank you for providing excellent customer service. I'm not sure if this far enough out of spec to matter or not, but your guage measured 0.071" with an electronic caliper. I'll be messaging you shortly on eBay. I understand that a nicer rifle doesn't equal proper assembly, I suppose I was trying to make the point that it's too nice to not fix.

[Patric78]

Hello again, my pleasure to assist you. And ensure product quality. I must say after your last post that the gauge is made to the specification that I use and here's why. And please folks, this isn't a contest between myself and other gauge producers. My gauges are as follows

GO: .064
NOGO: .071
FIELD: .074

I use these numbers based upon my personal study and findings from all the advise I gathered and info that was also presented to me. The information also concerned studies of other weapons and where their maximum allowable headspace rests vs actual incident. And personally I chose that using the absolute FIELD Maximum at .076 is a risk as a maker. Pushing that edge of functionality. The full picture included when thinking about this was a defining factor. And it is based upon safety for the user, the same user that may make a slight error in usage. So when someone has an issue and the gun is failing or closing over the field gauge at .074 they are alerted to take this to a knowledgable smith without pushing the limits of the military remove from service (dangerous) dimension of .076.

Therefore keeping a less than safe or on the edge of safe issue from having a chance. I cannot personally comment on the dimensions used by the other maker without further research, but I do know at one point a customer of mine compared the two and found them to be the same. Essentially he bought a gauge from them, misplaced the set and purchased another from me, of course to only find the others shortly thereafter.

Well apples to apples. Enough on that.

Hundids, I've sent you a complete set, watch for the yellow 6x9 envelope. And it includes my industry first Firing Pin Protrusion Gauge, just remove your bolt and carefully release the spring tension, place the gauge over the pin tip, letter side up and ensure the tip is just at the upper edge of the center hole... Be a sure strike every time! Oh and if it measures at .071. Forward that to a friend in need.

Thank you!

-Patrick


One last tidbit, I've produced a master set, with increments of one gauge at .063, .064.......all the way to .076! There are two folks with these and we have been studying to find the optimum functionality for headspace on these.. Still early but the number seems to be .067. Functionality, not accuracy.

[Enfield47]

Patric78, you sir have excellent service and should be applauded!

I'll look you up on Ebay when I need to buy something you carry.

[Patric78]

Thank you sir. I hope to actually find what the OPs rifle has going on. And by the way I do offer the coin style gauge set for 303 at a blistering deal at this time. Send me a message on eBay, if you have interest. Thanks again for the compliment. Stay safe.

[Bainter1212]

Thank you sir. I hope to actually find what the OPs rifle has going on. And by the way I do offer the coin style gauge set for 303 at a blistering deal at this time. Send me a message on eBay, if you have interest. Thanks again for the compliment. Stay safe.

Don't forget to put in your ad, that you can use the same gauges for 30-40 Krag. (At least I am pretty sure you can).

[Enfield47]

Thank you sir. I hope to actually find what the OPs rifle has going on. And by the way I do offer the coin style gauge set for 303 at a blistering deal at this time. Send me a message on eBay, if you have interest. Thanks again for the compliment. Stay safe.

Patrick, I ordered a set of the .303 British gauges from you this morning (actually my wife ordered them for me). They were at a great price, thanks for the heads up. It's nice to support someone like yourself and I'm looking forward to testing them out on my rifles.

[Patric78]

Most excellent! Just marked them shipped actually and will be sending along today (Thursday) Thank you sir! Hundids, hope to see that you received yours soon. I will be checking back. Have a safe weekend everyone.

[Twystd1]

Hey Patric.......

YOU ABSOLUTELY ROCK ! ! !

I am glad you are here at Calguns. Please come back to visit us from time to time.
You would make a great addition to the C&R collectors brain trust.

Cheers,
Twystd1

[Patric78]

Thanks, will be around for sure. Just checking back to see if any resolve was reached... I'll be back, hope everyone had a safe Independence Day!

[Hundids]

Thanks, will be around for sure. Just checking back to see if any resolve was reached... I'll be back, hope everyone had a safe Independence Day!

Hey Patric. Still waiting on the field guage to get here, I'll definitely keep you updated. Thanks.

[Hundids]

OK, so here's what's going on. Received the field gauge today, and it ALMOST completely closes with it in the bolt. Please review the pictures below to see the position at which it stops. Keep in mind, this is where resistance is first felt. I feel like I could close it all the way if I pushed hard enough. Is this thing safe to shoot or a wall hanger? I find it so funny, as I've purchased a few Mosins in the past and thought nothing of checking the headspace. The one I do decide to check has the problem going on with it.

[Patric78]

Couple of points to observe first. When dealing with metal, if you have to force anything it's probably wrong. So as per the instructions I included, don't force, doing so can cause adverse issues with both the weapon and or gauge. Secondly I sure hope you received the complete four piece set I sent, not just the field gauge... And last but not least I can't say legally that the weapon is safe, but if it does not close over the field gauge, you may have a headspace issue present.... Take this one and another, swap complete bolt assemblies, check both weapons headspace... If both check out fine, swap the bolt heads and check again.. Do this until you reach a desired result. If you don't achieve a better situation doing so, you have to make the call personally.

If it were mine I would attempt to get this to not close over the nogo. If I could not I would proceed with caution. Keep me posted. Glad to help however I can.