Would appreciate some quick help.
I am checking out an unkown mauser for my dad.
In the medium bore forum it was recommended that I properly identify the mauser before purchasing or altering but that I also measure the headspace.

Could someone please explain how I should measure this?

Is there anything else I should be inspecting for wear other than rifling and possible pitting or rust in chamber?

Would appreciate any advice.

Take it to a Gunsmith & let him do this for you.

Let a gunsmith check the headspace.

You can get a pretty good idea of how the bore looks by holding it up to the light and checking for pits and gunk etc.

Alot of military guns out there will have some pretty bad bores that can clean up into fair shooters.

Depending on what you plan to do with the gun (i.e. custom sporter) make sure the gun is worth putting money into.

-Spencer

You must have the chamber absolutely clean to perform a headspace check. You need, at a minimum, a NO-GO headspace gauge for the caliber that the rifle is chambered for. You hook the gauge under the extractor and feed it carefully into the chamber with the bolt. If the bolt closes, the rifle has excess headspace. If it stops short of full closure, the headspace is OK.

Look for rust, pitting, and general abuse. The better Mauser rifles were beautifully made with no visible tool marks. Wartime rifles got sloppy.

Clemson

Sounds unanimouis - gun smith with proper tools to check head space.

I will look up a local gunsmith and have a chat as to how much it will costs and if their is any possibility I could have a loan of his 7X57 headspace gauge, being the rifle is 330km from nearest gunsmith, and I am looking at paying $200Aus or approx $110US for rifle from a friend.

I am not all that sure what head space is
Does it refer to a larger chamber than specified and the shell expands when fired?

Or is it related to the seating depth of bullets but somehow different to where the lands engage the bullet?

Headspace describes the amount of room in the chamber for the cartridge when the action is closed. Cartridges vary in tolerances, as do rifle chambers. Having headspace within spec or tolerance insures safe operation with cartridges that are the proper dimensions...proper fit, if you will.

There are many ways to measure headspace as different types of cartridges "headspace", or chamber, differently. The rimless cartridges in your 7x57mm Mauser, for instance, "headspace" on the shoulder, and headspace is basically the room from the face of the bolt to the rear of the case head with the bolt closed. Measured in thousandths of an inch.

Many rimless pistol cartrides "headspace" on the case mouth, or rather the case mouth stops against a step in the barrel chamber, and a cartridge of proper dimension thus fits within spec in relation to the face of the closed bolt, which results in "proper headspace".

Rimmed cartridges seat with the rim of the cartridge fitting into a recess in the chamber wall, thus allowing the proper distance between closed breech and the rear face of the cartridge case head...."good headspace".

It's all a question of proper tolerance between breech and the soon to be fired cartridge. If it falls in spec, all is well...in a tired gun the "headspace" increases to the point that an in-spec cartridge might have too much room in the chamber, and thus not properly supported. This could result in a blown case or popped out primer...an undesireable condition prone to releasing quantities of searing hot gas into the action of the firearm.

A gunsmith will explain this all better and you should be sure to listen, and of course always wear your safety glasses when shooting....

Ah I see you are australian...I hear Occy has retired....he was my hero as a young man...best wishes to him....and you...

Well, robe...

This is allegedly a gunsmithing forum, but I don't see a lot of that here.

What's your budget?

If you can afford a couple of gauges, and are willing to spend some time learning... presuming you know the caliber, purchase the gauges, and take down the bolt, in particular removing the extractor, and see if the gauges fit.

Get the Go and No-go.

Hand feed them--this is why you removed the extractor--and, if everything is as it should be, the bolt will close on the "Go," and not close on the "No-go."

robe0280, the real magic in gunsmithing has to do with making stunningly beautiful stocks out of expensive pieces of walnut, and having the time and determination to fit and finish steel rifle parts.

I'm sad that you haven't been encouraged to learn to do this yourself.

Order the Roy Dunlap "Gunsmithing" book.

There are real talents here, robe0280, and I'm hoping you'll hang around and take the time to figure out who they are.

The best of the best.

I'm not certain where you are, or what assets are available, but...I hang around this forum because I want to lean from the masters.

Who post here, on occasion.

flaco

N.B. If you care to learn, Steve Wagner has written a sweet--although perhaps not uncontroversial--explication of headspace on his site.

A couple of light years ahead of any of the responses I've read here. So far.

You can find a little of this wisdom here http://www.gswagner.com/bigreloading/resizing/casemic.html

but I encourage you to linger on his site as long as you can afford.

If you cared enough to post here, I'll assume you care enough to learn how to do this yourself.

Or at least understand the whole not-that-complex dynamic that is custom bolt-action rifle building.

If you click on the link it will take you to a very good description of headspace.

http://p077.ezboard.com/fparallaxscurioandrelicfirearmsforumsfrm49.showMessage?topicID=6854.topic

A good trick is to put two layers of painters tape on the head of a cartridge and feed it. If the bolt closes, take it to a gunsmith. If the bolt won´t close without a good effort you should be all right.

I try this on all second hand rifles I get, but I always, that is ALWAYS, have them checked by my gunsmith anyway, if I´m going to use them.

Boha

Thanks all for your contributions and also the encouragement.


Not all the reason for me wanting to measure it myself was due to being a tight arse and no doubt the Gunsmith I choose will be getting 20 questions.

I spoke to a local one who had been recommended previously for making new barrels and he said he could fix poor headspacing rather cheaply and could be well worth purchasing the rifle even if the head spacing was an issue.

He also recommended for safeties sake putting some bits of paper between the bolt face and base of shell and CAREFULLY closing the bolt. He felt that one to two pieces would be safe enough to shoot but anymore and it would need fixing.

I will post some details for the identification of the rifle in the medium bore forum early next week. I would appreciate some help identify the potential for this rifle. Worst case hopefully it will provide dad with a cheap entry deer rifle or best case It might make my first full project.
Recently redid the stock on dads Anschutz .22 which came up really well

There is something here that most of us are missing and has to do with all rifles but mostly to the bunch of Milsurps out there as it relates to headspace and specifically lug setback in the receiver. Simply by using the go/no-go gauge will tell you only if the headspace is correct or not ONLY WHEN CLOSING THE BOLT. What I am trying to say here, is when you try to close the bolt on the no-go and it won't allow the bolt to close, the bolt lugs are trying to cam over the receiver/lug engagement. Now, look at this; if there is setback in the receiver, if you were to get the no-go into the chamber with the bolt fully closed you may be able to detect an out of spec headspace. The only way you could accomplish this is to remove the barrel, insert gauge and screw action onto the barrel with the bolt in place and fully closed. Seemsa like a lot of work just to check headspace. Here is another, easier was. If the bolt closes on the go gauge, and assuming the bolt has been fully stripped, set a dial indicator against the back of the bolt and move the bolt fore and aft. If there is excess headspace, the indicator will tell you in thousandths of an inch how much. Simply by perusing the specs for the cartridge will tell you if you have excess headspace and lug setback. "Comprende"???

Jim

Thanks Jim Kobe
Appreciate the extra info on headpsacing although will need a bit of a heads up to follow closely.

Am a little unsure on what 'lug setback' is.

From what i understood closing a bolt on the no go would mean the chamber has been stretched or erroded to such a state that it is to large for a spec shell.

Have i interpreted this right? That if the no go has reached the end of the chamber it may have the bolt to far back in the receiver and the bolt won't close, not because of head space but, because the lugs are contacting the receiver lugs.

Could you explain how you would use a dial gauge in greater detail for me. Specifically how to identify the starting spot presuming the end would be when the shell contacts the chamber.
Thanks
robe

Dear robe...

Well, one of the master's has indeed posted!

Jim Kobe is one that I would put in that category.

I've only handled one of his rifles personally, but you can visit Jim Kobe's webpage

and make up your own mind. Make sure that you click on all the pictures to get a big image and really appreciate his workmanship!

In short, the guy really knows what he is talking about!

Just my opinion, of course (worth twice what you paid for it!

jpb

Who is the "robe" guy anyway?

Seriously, in order to check lug setback, which is the lugs crushing the lug contacting surface in the receiver due to a number of reasons, if the bolt will close on a go but not a no-go really, as I said earlier, is not a sign that there is not excessive headspace. WIth the go gauge in place and the bolt closed, a dial indicator is placed so as to contact the rear of the bolt, then move the bolt fore and aft and observe the indicator movement. If you have setback which equates to excessive headspace, the indicator will show how much movement in the bolt which is also the amount of excessive headspace depending on the tolerances between go and no-go. Comprende'

Sadly,

Almost no so called smith you take your milsurp to for a headspace check will test it the way Jim describes.

The majority will simply do as flaco said and slip a gage in, sometimes even taking off the extractor, and try to close the bolt.

I think it is interesting that no one has mentioned the care with which the headspace gauge is used.

One of the several principal reasons the extractor should be removed before attempting to chamber a headspace gauge is so that you can "feel" what is happening with the gauge.

It is possible to close some bolts on No-Go gauges even when the chamber WAS within tolerances, with possible resulting damage to the gauge, or even the chamber.

The object is to see if the gauge chambers with NO resistance. To do that, you need a clean chamber AND a clean gauge.

Remove the extractor, clean the chamber and gauge, then feed the gauge CAREFULLY into the chamber (without having put it in the magazine), pushing the bolt straight ahead.

When the bolt is as far ahead as it wants to go with no appreciable felt contact, see if the bolt handle closes with no resistance. If it does not start to close, then remove the bolt and the gauge. The gauge is larger than the chamber.

If the bolt handle starts to close, but does not drop all the way down, DO NOT go ahead and see if you can close it with even slightly more force. Doing so will cause the bolt cams to force the gauge into the chamber, steel against steel, and quite likely damage one or both of the gauge and chamber. Once again, just remove the bolt and gauge. Again the gauge is larger than the chamber, though possibly only slightly so.