No go gauge still fits

[toolz568]

I am finishing my first Mauser 9.3x62 rebuild and after tightening the barrel, the no go gauge still fits. Do I try to tighten it a little more or send it back to the gunsmith?

The barrel did move a little when I was tightening it, but it is tight.

Thanks,

[leebuilder]

Not sure whats going on, look for crud. If you still got a bit more on tightening some thing is not right. You should not go over 65 foot pounds of torque for most mauser actions. What gauge was the original install fitted to?
Be safe.

[fouronesix]

Yep, not right.

You can unscrew it, wire brush (both the barrel shank and the receiver), flush with solvent, add a dab of anti seize and try it again. But a no go gauge is likely telling you it is not right. It may be a simple fix at the gunsmith's. Could be the barrel shoulder (or receiver face) needs skinning back and/or the breech end of the barrel trimmed where it butts against the pressure ring in the receiver (if the receiver has that ring). Once the gunsmith checks those two contacts and re-fits- have him check with both a go gauge and the no go gauge (he should do that as SOP anyway).

[country gent]

Very carefully cut some discs of shim stock .001, .002, .003, .005, and .010 with a thin oil or grease start with no go gage plus .001 and check then work thru the shims till it just dont quite close or closes snug. If you use the go gage even better then you know how much has to come off the barrel shoulder and face to set headspace. If there are holes for sight mounting you may have to go a full revolution and then rechamber to headspace the new barrel. But using the shims will tell you how much it is "long" and give an idea of what to do.

[RustyReel]

I am finishing my first Mauser 9.3x62 rebuild

I see you use the term rebuild.....was it a 9.3x62 before you started?? Did you remove and are reinstalling the original barrel??

[toolz568]

I will try the shim idea and see how how far it is out and then take it apart. As for a rebuild, it was a Mauser 30-06 that was poorly sportorized. I spent a lot of time trying up the action and polishing the faces. I ordered the barrel tapered, threaded and crowned so I can always send it back if it needs to be adjusted.

[Watermelon Wine]

You can order 'pre-chambered' barrels that are 'short chambered', and intended to be deepened to correct headspace with the chamber reamer, and 'long chambered' that are headspaced by facing the barrel in a lathe. Either method saves a lot of tedious work but the short chambers may suit people with reamers but no lathe, and the long chamber may suit people with lathe but no reamer.
Are you sure that it was not supposed to be one of these? "I'm happy to fit it myself" can mean different things to different people!

[nekshot]

I have no business giving advice of these matters but I always put masking tape on the back of a cartridge till the bolt starts to bind. You have been adviced to use shims which is the correct way. If you have a empty cartridge that was fired in another gun can also be interesting to see how it fits. Your no-go gauge might be off size and you are ok. This is why I like field gauges. If you adjust your dies and only you use your gun that might work also but first you must see how much extra room is in chamber.

[M-Tecs]

Proper shim stock material is allows preferred, however, all sorts of materials can be used in a pinch . The clear plastic from cigarette packs is the thinnest you will commonly find. Scotch tape also works. Just build up the go gage until you feel some resistance than measure the total shims. This will give you a ballpark number.

Depending on the cost to fix it you may want to consider fire forming your brass to the chamber and calling it good.

Even with closing on the NO-GO the chamber may still be under the SAAMI max.

http://www.forsterproducts.com/store.asp?pid=24834

Forster offers three lengths of headspace gages per rifle caliber. In order from the shortest to longest, they are: GO, NO-GO and FIELD;

1. GO: Corresponds to the minimum chamber dimensions. If arifle closes on a GO gage, the chamber will accept ammunition that is made to SAAMI’s maximum specifications. The GO gage is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gage is necessary for a gunsmithor armorer, it usually has fewer applications for the collector or surplusfirearms purchaser.

2. NO-GO: Corresponds to the maximum headspace Forsterr ecommends for gunsmiths chambering new, bolt action rifles. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gage, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gage. The NO-GO gage is a valuable tool for checking a newly-reamed chamber inorder to ensure a tight and accurate chamber.

3. FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gage, its chamber is dangerously close to, or longer than, SAAMI’s specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gages are slightly shorter than the SAAMI maximumin order to give a small safety margin.

http://thecmp.org/training-tech/armo...ner/headspace/

[John Taylor]

I have used masking tape for years to get an idea of how much head space there is. One layer is about .004" and you can keep adding layers until you feel a drag on the bolt, measure the layers with a micrometer and you know how far to go. With lever guns, if you set them close on a go gauge they might have problems opening after firing. I have had Winchester 94s come in with .025" head space that had been used that way for years. At 42,000 psi the 30-30 brass usually won't stretch, don't try it with higher pressure like a 30-06 or you might get head separation.

[toolz568]

Thanks everyone, I have shim stock and I am .007 over the go gauge and .002 over the no-go gauge. I do not believe the barrel was fully torqued as it slipped, but it was tight. I disassembled it to clean the threads and check the action. Watermellom Wine might be right and this barrel was not short chambers. Looks like it has to go back to the gunsmith as I have a reamer, but I am not sure I want to attemp this on my lathe.

thanks for the help,

[fouronesix]

.007 and .002 sound about right as there should be a nominal .006 difference between the two. All you need to do is remove about .004-.005 from the barrel shoulder and barrel breech face end to be within nominal headspace specs. The only thing to watch for (and trim accordingly) is that the barrel shoulder contacts the receiver face at about the same time as the breech face end contacts the pressure ring when the barrel is tightened up. Having the reamer is very handy in case you go a little too far. Then it's very simple to ream the chamber a smidge back to a comfortable, small amount of headspace clearance. Easily done with a T handle while the barrel is in the action.

Anyway, a decent gunsmith would do the same thing with little problem. But a good call if you are uneasy about doing it.

[country gent]

It is easy enoughto do now. chuck barrel in lathe and indicate in muzzle and breech with shoulder out about 1" from jaw faces. coat sholder and barrel face with layout blue or magic marker. Grind a facing tool from a Hss lathe bit so that you can face the barrel into the thread relief. With a depth mike measure face to shoulder write this down. Set compound to 90* or parrallel to bed and just touch the shoulder make a pass to clean up face and remeasure take remaining amount from shoulder. repeat on face of barrel.