Warped Bolt?

[680guy]

I purchased a sporterized 93 mauser . My best guess is that its an early Spanish short rifle. It has a 21.5" barrel simply marked "7mm" and serial number 8815 which matches the reciever. It has no crest or any other markings except for "DUETSCHE WAFFEN-UND MUNITIONSFABRIKEN BERLIN'' on the left side of the reciever which has no thumb slot but a solid rail .The bore is shiny the rifling is sharp the overall condition is quite good . The bolt appears to have been welded by a pro, very nicely finished the work appears to have been done years ago, but there's a problem. Once I got it home I realized the bolt shrowd was backed out one thread . I turned it in but then the firing pin protruded when the bolt was open. I discovered the cocking piece had peened the notch in the bolt deeper . I filled with a small spot of weld, filed it back to original condition checked the head space. I loaded up some mild loads and shot the rifle at 40 yds. Every shot landed in a differant corner of the target I couldn't get any kind of group. I checked the scope, mounts and crown all seemed ok. Then checked the primers on the spent rounds. I found the were all hit way off center and the bolt face tell me that it's had this problem for along time. I suspect the early bolt work as nice as it looks may have gotten way to hot and warped it but would this explain the accuracy problem? I have a turk that strikes off center but is still accurate. Guy

[Doble Troble]

Interesting...but I'm at a loss. This may be a learning experience for everyone. I'm sure the experts will have advice soon...and I'll be listening.

[Thor]

I somewhat doubt that is the cause of your scattered (non) groups. That crown may not be as good as you think. Regardless of that, if that bolt was exposed to enough heat to warp it, I certainly wouldn't trust it.

[BobVZ]

680guy,

 

Unless your '93 was converted to cock-on-opening the firing pin should be exposed when you open the bolt.

My 1916 carbine has off-center primer strikes as well. I discovered two reasons - improperly machined boltface and barrel liner slightly off-center. I would check the action bedding to make sure action is not being sprung when tightened. Also, try a different scope. It is possible the reticle may have shot loose.

 

Bob

[tinkerfive]

Before you do anything with the rifle, what's up with the ammo?

You don't say what you are using.

 

I had an experience with an 8MM that makes me question the ammo.

I was using some "cheap Turk surplus" to sight in and get close then

swich to the "good ammo".

Well I was getting about a 3" group with the "cheap Turk surplus" when

I decided it was time to swich to the "good (Mitchels Mauser) ammo".

Well my target was on a 2' square piece of plywood and I was lucky to

hit the plywood with the "good ammo".

 

Bottom line, before you go screwing around with the rifle, be certian that

the ammo is good.

 

Tinker

[680guy]

680guy,

 

Unless your '93 was converted to cock-on-opening the firing pin should be exposed when you open the bolt.

My 1916 carbine has off-center primer strikes as well. I discovered two reasons - improperly machined boltface and barrel liner slightly off-center. I would check the action bedding to make sure action is not being sprung when tightened. Also, try a different scope. It is possible the reticle may have shot loose.

 

Bob

Bob On this rifle, there are two notches on the back of the bolt, one deep notch where the cocking piece falls when the bolt is closed and the trigger is pulled. The other is shallow, where the cocking piece rests when the bolt is in the open position. The tension from the firing pin spring holds the cocking piece and prevents the bolt shrowd from turning (unscrew/tightening). On this bolt, the cocking piece had dented and peened a ridge up on the outside edge of the shallow notch and on the inside of the notch you could see where the original hieght was because the cocking piece didn't fall there. When the bolt was open, the firing pin protruded so far that when the bolt picked up round from the magazine the firing pin blocked it from sliding up into the bolt. This rifle cocks on closing. I thought that this might also have been a symptom of over heating the bolt ,but,its more likely the result of a century of use. I think your right ,first I'll try a different scope. I've already cleaned up the crown , haven't shot it yet. Hope it works it's a neat little rifle. Guy

[Thor]

Guy,

one thing for certain, in your last post you made it very clear to me that you fully understand the function of a Mauser and your description supports what I know. I'm not familiar with the DUETSCHE WAFFEN-UND MUNITIONSFABRIKEN BERLIN models, but sounds like what I'm familiar with in Swedes, Loewes and 98's. (Is this one like a Swede and Spanish 95 or closer to the Loewe 91 actions?) As you say, the firing pin does fall against a different notch in the fired position and the open bolt position, and the firing pin should not protrude in the open position. I can understand your concern and in fact am surprised you didn't experience a slamfire while closing the bolt.

 

Again, I don't believe that is the problem with your accuracy. Check your scope again, check the bedding for binding, start from scratch on all of it. I've bought "bubba" rifles before, some as you say, finish looked good but shot like crap and closer examination showed problems. I do know that bedding and crown is first place I start. I also like a free floating barrel on sporter stocks. Any binding is going to cause problems.

 

The bolt problem, if warped, could possibly have caused irregularities in the lugs, but that's usually a "finetuning" issue, getting 1/4" MOA, not just trying to keep it on the target and inside 6 inches.

[BobVZ]

680guy,

 

The firing pins on M93's & 95's do actually protrude slightly from the boltface* in the unlocked position, but not enough to affect feeding. It doesn't slam fire because as you close the bolt it cocks and retracts the firing pin. M96 Swedes do retract the firing pin from the boltface because they partially cock on opening. If your firing pin protrudes excessively, the pin is either too long or the cocking piece allows the pin to travel too far forward. Since your bolt shows peening in the cocking cam notch, I am suspicious that a previous owner may have ground back the face of the cocking piece, perhaps in an effort to fit a safety, and this is causing the sear to impact the notch. Forward motion of the firing pin is halted by the impact of the cocking piece face with the interior mating surface of the bolt shroud. The sear projection should not contact the bolt. You may need to inspect and replace the cocking piece if this is so.

 

Bob

 

 

* "Bolt Action Rifles", 4th Ed., p.133. F. de Haas

[Racepres]

At the risk of showing my ignorance, I will say that I would also measure the length of the firing pin itself.. MV

[Thor]

The Mauser design is as 680guy describes, as early as 1891, regardless of whether Argentine, Spanish, Swede or even into the 98 series. It was part of the "MAUSER" design to lift the firing pin into a "safe" position while cycling. Mauser desired to avoid a slamfire. If you have a Mauser which has a protruding firing pin in the open position, you have a defective situation. I would suggest that probably the sear surface on the cocking piece has been filed down enough that tolerances have changed. In that case, the firing pin needs to be shortened to correct the dimensions. Racepres is right on in saying the firing pin needs to be measured, both in the safe position and also in the fired position. It should not protrude in safe position, and should not penetrate deep enough to puncture a primer.

 

Guy, I would suspect a filed sear surface more than a pinged notch. It is just hard for me to see how the notch could be pinged that much.

 

I don't have a Spanish Mauser at the time, but I do remember the one I owned a few years ago, and a couple of others belonging to friends, and I can't remember them being different than my Swedes in design. Certain things in Mausers is like Gospel, canonized. Lifting of the firing pin to the safe position is part of that Gospel.

[680guy]

Thanks for your help.Your suggestions led me to examine the cocking piece more closely and I think I see a problem with it. Where the cocking piece meets the bolt, the cocking piece is beveled back on the inside so that only 1/3 to 1/2 the thickness of the bolt wall bears the strike of the cocking piece on the outside edge of the bolt. What had been peened up was just the outside edge of the bolt.

This rifle has a very stiff firing pin spring. It's only a guess, but if the shooter lifts the cocked bolt without a firm grip on the bolt ,the bolt will spring back completely open and the cocking piece slams forward nearly an inch, much like dry fireing. If this was the original cocking piece, over 100 years of opening the bolt could have caused the wear I found. I do see wear on the caming surface of the deeper notch, again along the outside edge but very little in the bottom of the notch but if the previous owners had the good sense not to dry fire exessively that would make sense. I can't imagine why anyone would have altered that surface of the cocking piece, perhaps it was made that way, in any case I'm ordering a differant one and see how that looks. Again, thanks for all your comments, Guy

[Thor]

Guy, are you talking about the underside below the part that fits into the notch? Why would anybody bevel that part? Now I'm really puzzled, but yes, you need a new cocking piece.

 

That camming surface is surface hardened. Dollar to a donut the surface is worn and needs to be reheat treated. I've never done it, and wish I had that skill.

 

Does anybody know the spec for the firing pin protrusion in fired position? A couple of times (out of several hundred), I've had a punctured primer. It's scary to say the least. It would be good to check all my Mausers to make sure they are within spec.

[z1r]

 

Does anybody know the spec for the firing pin protrusion in fired position? A couple of times (out of several hundred), I've had a punctured primer. It's scary to say the least. It would be good to check all my Mausers to make sure they are within spec.

 

0.055" +/- .005"

 

[Thor]

0.055" +/- .005"

Thanks. I'm sure I've seen it before but ignored it. Some of these threads prompt me to check such things.

 

[z1r]

Excess headspace can cause punctured primers too.

[680guy]

Guy, are you talking about the underside below the part that fits into the notch? Why would anybody bevel that part? Now I'm really puzzled, but yes, you need a new cocking piece.

 

That camming surface is surface hardened. Dollar to a donut the surface is worn and needs to be reheat treated. I've never done it, and wish I had that skill.

 

Does anybody know the spec for the firing pin protrusion in fired position? A couple of times (out of several hundred), I've had a punctured primer. It's scary to say the least. It would be good to check all my Mausers to make sure they are within spec.

Thor, sorry I couldn't explain it better. If you have a copy of Kuhnhausen's "The Mauser Bolt Action" on page 47, "Detail Inspect Cocking Piece" he calls the area I'm talking about the "bolt hold open cock surface" . On 93 -96 mausers that surface is on the same face as the sear engagement surface. The sear contacts the lower area, the bolt bears directly above it. On this bolt, that area is beveled back. Today I got chance to look at in better light and through a magnifying glass. It hasn't been filed, but is also smashed and peened. The bolt shows serious galling on the quarter cock cam and the firing pin port is egg shaped. I think that beautiful bolt that caught my eye at the gunshop is going to have to be replaced. Oh well, at least I've learned alot from this rifle. Seeing the galled surface on the bolt has me, again, wondering if the heat of the bolt job softened the metal.

[Thor]

Yeah Guy, I thought that was the surface you were talking about. So the culprit wasn't a file, it was peening and galling. Magnifying glass is a wonderful thing, except... You can't hide the truth. So now you are in the market for a bolt and can only hope you get one that headspaces reasonable.

Yeah, the heat of the bolt job would have taken the surface hardening out. But what would have softened the cocking piece? I use a heat sink and also use heat paste on bolt jobs and believe in working fast. The longer the job, the greater the risk.