I bought a Brno barreled action, the boltface of which has a ring of pits around the firing pin hole, fairly deep. Is there someone out there who can weld up the pits and reface the bolt?

This same action also has 3 holes in the side for a side-mount scope system which I would also like welded up.

Thanks!

[ 08-26-2003, 00:25: Message edited by: fla3006 ]

Why would you want to? I would be afraid of changing the heat treatment of the lugs. does it affect the operation of the rifle?
sounds like primer leakage.

[ 08-25-2003, 01:45: Message edited by: arty ]

If there's no way to do it without weakening the metallurgy, I won't.

[ 08-25-2003, 05:09: Message edited by: fla3006 ]

.......Fla3006, in many milsurps it's not uncommon for there to be a corrosion ring around the firing pin hole. This due to primer leakage and the corrosive primers then causing the damage.

If it's not too bad a gunsmith can cut the boltface a couple thou deeper an eliminate it altogether, or to the point where it isn't causing bolt lift problems after firing. Bear in mind that if at the limit already, the barrel may have to be set back and re-qualified.

If there aren't any problems in operation (have you fired it yet?) then I wouldn't even worry about it. I built my daughter a deer rifle many years ago using a Brazilian M98/08 action. It looked like someone had used a small roundnosed punch around the firing pin hole in the boltface. Why, or to what purpose I can't say as they weren't close enough to the hole to have been to close up an eroded firing pin hole.

These slight dimples allowed the primer face to swage into them. The only problem, and not a major one, was that bolt lift after firing was a bit harder. No big deal really. If it's just cosmetic I wouldn't worry about it.

........Buckshot

The barreled action is scarce, commercial ZG-47 30-06, made in 1956. Original owner must have fired corrosive military surplus ammo in it. The pits are fairly deep but I'm sure it will still fire safely, just looks bad. I'm planning to make a custom rifle with extensive modifications and prefer the bolt face look as good as the rest.

If it really bothers you get another bolt.

For the kind of rifle I intend to build, it does bother me, and clean bolts for ZG-47s are even harder to find than complete rifles. They are different from any other kind of Mauser bolt:



[ 08-26-2003, 00:22: Message edited by: fla3006 ]

One trick I've used is to drill and tap the bolt for a large size set screw which is seated in reverse. re -drill the firing pin hole ( using a Lathe) and use High Force 44 solder to hold in place. Clean up the bolt face on the Lathe and your done! This is a nice trick for also fixing oversize firing pin holes or making new smaller ones. set screws are made of hardened steel so no problems there and the heat used with Hi force 44 solder won't effect the heat treatment of the bolt.-Rob

Sounds like all you need to do is send the bolt to Robgunbuilder.

Rob, how much for that job?

Yes Rob, approximately how much for that job, and can you also weld up the 3 holes in the side of the receiver? Thanks for the professional reply.

fla 3006, 50 some odd ZG 47's through my hands since about 1951 when I saw my first one doesn't make me feel like I am expert with them, but the majority of them got upgraded with better bolt bodies. Some owners preferred to keep the work of manufacturing art bolt sleeve and backwards operating type safety lever. Most dumped the serviceable, but again alien to North American preferences trigger unit. The trigger was virtually interchangeable, part for part with the pre-war Mauser-Werke special order single pull trigger, but that didn't deter even Mauser nuts. In order to keep the looks the same I sometimes had to cut off the old bolt handle and re-install it on the new bolt body. This also meant milling or grinding a flat for the safety bolt lock position on the rear collar of the bolt body when the ZG bolt sleeve was being retained.
I did a detail survey of the ZG 47 differences against standard '98 for Jack O'Connor, that he might have the info in his files for his mail bags full of inquiries in case the subject came up. Essentially this was, that the barrel threads were of same diameter as large ring mauser,but 60 vee and 2 m/m pitch, The guard screws were normal mauser nominal shank and head diameter but reduced for a M6 x .75 thread pitch- standard European metric form, and the bolt stop receiver ears and pivot hole were located 1 m/m further to the rear and the stop face of the bolt stop lug itself was also 1 m/m further to the rear. The receiver itself in the earliest production were obviously milled with the inventory selection of cutters left over from the Nazi occupation days on the underside to include the trigger sear lug trapezoidal shape. The bolt being positioned 2 m/m to the rear allowed for a lot more wobble because the bolts were as it later became known made from semi or at any rate uncompleted WW-II bolts which were maintained at about .695-97 " diameter at the lug end and having less entry into the bridge (thus) caused the wobble. Cosmetically the bolts were also undesirable to many because the bolt guide ribs had grooves milled into the cylindrical part of the body to speed up polishing out the rougher machine marks from war time production Diktat. The other parts differed cosmetically in the bolt- receiver group. The VZ 24 Military bolts tend to be the ones where you can find business end diameters at or near .703" diameter and they make a wonderous difference in the ZG receiver/bolt fit. When it was elected to keep the original barrel the replacement bolts headspaced to same gage plus or minus negligible ( in 1/2 thousandths)
It has been reported to me from time to time that some ZG's came without a guide rib on the bolt. When several were sent to me for bolt alterations the owner's alleged that the original bolts were trashed because of this. One said he had a receiver that was not machined for a guide rib. When I allowed as how I could machine that feature in for him and fit up a bolt, he had "already traded the action off". So I have yet to see one like this.
In all seriousness,inasmuch as I have carefully detailed the differences and corrections that can be made in the preceeding text, I would like to know what differences you have found in your ZG 47 from those I have handled and measured that prevent the substitution of a decent Czech made standard '98 type bolt. I would indeed write this down in my ZG file and attribute to AR correspondant fla 3006, and thank you in advance.

[ 08-26-2003, 04:33: Message edited by: systeme98 ]

Mr. Burgess- I did not mean to imply that no other Mauser bolt would work in my action. But I like and prefer to retain the original and unique bolt handle even though it doesn't clear low mounted scopes as well as some others, and I would prefer not to cut the handle off and weld it onto another bolt body. Wouldn't it be easier to repair the face as Rob outlined than cut off the bolt handle and weld it onto another bolt body? And for aesthetic reasons, I also like the fact that the bolt is numbered to the action. I plan to rebarrel the action, so any headspace deficiencies, if there are any, will be remedied at that point.

My original question seemed simple enough. Maybe there is no way to weld up small pits on a bolt face without weakening the face and lugs, but at one time there was at least one prominent member of the Gun Guild who could do it, did them on old Rigbys, etc. Thus far, Rob's solution seems like the best to me.

All my ZG-47s (14) have regular Mauser-type bolt guide ribs and I haven't noticed that the bolts wobble any more than other Mausers. And as far as the safeties on Brnos being backwards, I never have trouble remembering how to operate them. Just like cocking a hammer gun.

[ 08-26-2003, 18:33: Message edited by: fla3006 ]

As for holes in the receiver, I can tell you exactly what needs to be done and how, but you need a really good technical TIG welder. I have all the proper gear, but my skill set just isn't up to this in all honesty! I have a Model 30 Rem receiver on my bench which I keep as a momento to just how tough this problem really is! And the consequences of doing it wrong!
What needs to be done is the holes in the receiver sidewall need to be drilled out and the holes tapered with a taper reamer.l, Cleaned with Carbon tetrachloride and acetone, then TIG welded using the lowest possible amperage with HF start only. Use a Rockmount industries Tartan TIG rod ( tripple deoxidized) rod and just fill the holes( much easier said than done) without any pitting( watch the gas flow). I've practiced and practiced and practiced and I can do it about 50% of the time. If it pits you basically have to start over and risk overheating the action and ruining it's heat treatment. Then the action needs to be set up in the mill and the weld metal that protrudes milled out of the inside receiver sidewall.
If all goes real well, you can use a piece of cardboard tube with emery paper glued to it to sand down the welds on the outside to match the receiver sidewall, then re-blue.
If all doesn't go well you have a wrecked receiver or one that will need to be extensively recontoured, and re-heat treated. This spells Big Bucks. By the way, I have no problems with filling holes in the action rings themselves as there is alot of steel present. the sidewalls are something else!
All in all, I've deceided not to risk this and just plug the holes with screws and live with the knowledge it could be worse!
I'm going to plug two holes in a Greener GP shotgun bolt in the near future using the method I described and post some pics. I'm not doing any commercial work right now, but I'm sure John Ricks could take care of you just as well.-Rob

[ 08-26-2003, 08:55: Message edited by: Robgunbuilder ]

Thanks very much, Rob. Good answers.

R.A. Walsh's gunsmithing book, MAUSER M98 & M96 describes a method of welding up the pitted bolt face. He says to make a stepped plug that fits tightly in the firing pin hole with the larger diameter about .180". Press plug into firing pin hole and Tig weld around the larger diameter to fill the corrosion ring. Machine the plug off in a lathe and drive out the plug in the firing pin hole. He says the bolt does not have to be recasehardened.

I have never tried this but I suppose it can be done if you can weld it up without changing the color of the locking lugs. Possibly doing it in small sections and letting it cool between.

Hart

fla3006

If you need to locate any parts let me know, the coon hounds are waiting to go for a mauser sniff

If shouldn't be impossible to weld the bolt and have it rehardend. Drilling holes for a side mount in a mauser receiver should be punished by death, no pardon no plea

/ JOHAN

[ 08-26-2003, 21:44: Message edited by: JOHAN ]

Johan- The barreled action in question is for the 404 project I emailed you about although I'm starting to have 2nd thoughts about a 404, maybe a 9.3. Sure, if you know of any parts for sale, let me know, maybe there are some in Sweden. You sure won't find many in the U.S. (ZGs weren't imported here and only 20K were made)
Hart- I have that book, I'll check it out. Similar to Rob's solution.

[ 08-26-2003, 23:31: Message edited by: fla3006 ]

Unless one designed a coolant flow system similar to that used in a TIG torch head to ensure that the bolt locking lugs were not effected by the heat of TIG welding, you will almost assuredly experience set back of the bolt locking lugs following that process. Frankly there are a number of shops that specialize in re-heat treating( actually case hardening) Mauser bolts and if you just have to weld on one, I'd spend the money and have it re- case hardened).-rob

Johan- I've imported a number of guns, know how to do it. Next time you know of any good deals (or even not so good deals!) on Brnos or other nice Mausers, clue me in! You're right, it's a bad affliction.

fla3006

Let me know what your latest desire is , it much easier to look then... send an e-mail or so.

/ JOHAN

Johan you have any STG44's or FG/42s? I have lust in my heart for both of these.

Years ago I had a Mauser come in the shop that someone had messed up the bolt face. It was a Kruz in 250 3000. After a lot of thinking and measuring.
The way I repaired it was to set the bolt up in the lathe. I bored it out to the diameter of the face and made a recess in the face about .030" deep.
I then made up a plug out of 4140 and pressed it into the recess. Put it back into the lathe and faced it to the proper headspace. Drilled a new firing pin hole, and ground the ejector slot in the bolt face bushing.
Done properly you will never see it.
Jim Wisner