There have been many discussions about the Mauser action being opened up A'la Selby's gun. I remember years ago, reading an article where the gunsmith worked the standard action over(I cannot remember the cartridge) so that he not only had good bolt lug contact at the front, but also had good lug engagement on the rear "safety" lug. This seems to me to be as good a compromise as you could ask for when doing this conversion. I am curious if any of the gunsmiths here have ever tried to get third lug engagement and what issues they encountered doing it. I am assuming that after lapping the front lugs in enough for rear engagement, you would have to reharden the action, or would you build up the rear action lug recess with weld and then mate it? Is the safety lug area case hardened?, I would assume so. Thoughts?

Interesting question but more to the point has there ever been a recorded instance of where an opened up Mauser or Pre-64 M70 Winchester (same opening up process used by the Winchester factory on their standard action for the 375H&H) given way at the bottom lug recess?

If the answer to the above is no, then why try and fix something that doesn't need fixing.

I've put a lot of rounds through my opened up Mauser and Selby likely did to, at least that's two who had no trouble

Eagle: Thanks for that! I too, get pretty sick and tired of all the hype on this non existent problem

I have read about, I think in De Haas' book on bolt actions, that one FN cracked the top lug because it bore most of the back thrust. And that lug was probably too hard in the first place. That is the only one I have ever heard of, in how many thousands...
And no, making the safety lug contact is not worth all the trouble it creates.
Now, I do cut as much rearward as possible, even moving the box rear panel, but that is just a feel good exercise for me, not for any valid reason.

I hope you guy's got my point. I also, have several opened actions to 375 and 416 Hoffman and rem. I agree that it is a non-existant problem. When I remembered the story that I had read years ago, I thought to myself, "That is a novel approach that I had never heard of" which, in the never-ending thirst for knowledge, I decided to ask some of the great 'smiths that we have on here, what they thought and if they had ever heard of or had done this. Not advocating it, just wanting some expert opinion. I can't help but think, that if properly done, it would add something, but it would be a real pain. This subject was brought up simply for theoretical purposes!

quote:

Originally posted by lee440:
I hope you guy's got my point. I also, have several opened actions to 375 and 416 Hoffman and rem. I agree that it is a non-existant problem. When I remembered the story that I had read years ago, I thought to myself, "That is a novel approach that I had never heard of" which, in the never-ending thirst for knowledge, I decided to ask some of the great 'smiths that we have on here, what they thought and if they had ever heard of or had done this. Not advocating it, just wanting some expert opinion. I can't help but think, that if properly done, it would add something, but it would be a real pain. This subject was brought up simply for theoretical purposes!

No problem with your question and it could also be asked of any Mauser action with the third so called safety lug irrespective of whether it's an untouched action or an opened up one.
If the third lug is not in contact with the seat and the bolt lets go at the front is the third lug alone sufficient to hold the action together?

The bottom lug recess (feed ramp) of an opened up 'weaker' action cannot set back or shear unless the top lug also sets back or shears. If this scenario happened I don't imagine the small third lug is going to hold it all together.

Who knows if Mauser, or anyone, ever actually did tests on this aspect.
Grind off the front lugs and fire a M98 and see if the third lug alone holds it all together.

Out of curiosity I followed up on dpcd's lead and re-read de Hass in his 1974 Bolt Action Rifles book. He was talking about an FN No. 5 action, which was their Magnum model, a standard sized action opened up in front for the .300 & .375 H & H cartridges. He built the rifle that failed, it was chambered for the .300 H & H Improved, and as dpcd correctly recalled, the bolt's upper lug cracked off, specifically the left half of the upper lug. De Hass does not mention that the bolt was too hard, BTW. He says that he examined the damaged rifle and believed that because "It's owner fired it quire a bit with heavy, but I do not think excessive, hand loads", it eventually developed lug set back "due entirely to weakening of the lower locking shoulder in the receiver when it was altered". He goes on to say "I have concluded that the No. 5 FN action is OK for factory-loaded 300 and .375 H & H Magnum cartridges (which he says elsewhere normally develop less than 50,000 psi breech pressure), but it is not suitable for hot Weatherby or similar wildcat cartridges".

For anyone that is interested, this is on pages 175, 176 & 177 of his original book, it contains much more detail than I have been able to include here.

I thought that was the reason Roy Weatherby designed his mkV action .
He was having too many issues with the Mauser and his 300 Weatherby .
And yes I have made the safety lug contact .
Just to see if it would help with a wildcat .
I've had a few thousand bolts to search thru to find a suitable bolt and almost a thousand receivers .
I made 3 piles for each , worked down to about 12 bolts 2 receivers . I'm not sure if I still have that hanging around .

Out of curiosity, how did you come across a few thousand bolts and receivers to play with?
Will the safety lug alone hold? It was used alone, for the GEHA shotguns.
I suspect it would hold fine for some number of shots; back thrust on dry chambers is not as much as you think. I will do a test if someone will send me a bolt. I will supply the receiver.

Hopefully we are all on track, I know Gary is. We are talking about all 3 lugs being in contact when the bolt is in battery. This would make a three point lock-up. Whether the safety lug by itself would hold much, is another issue. That sure would make an interesting test though, to cut off the forward lugs and do a failure test. Too bad I don't have an old Geha bolt laying around, I will look through my junk for a regular 98 bolt. Anybody have any idea on what the normal contact clearance is on the third lug on a regular 98?

.030 or so.

Thanks, Tom. Theoretically, would it make more sense to anneal the bolt, Tig up the rear of the lug and fit it, then re-harden the bolt?

At one point in time I read where somebody did the lug removal test. Problem is, I can't remember the results.

Ackley maybe ?

First Mauser I ever got was a late war Brno, no guide rib rough as guts bitsa that was rebarrelled to .308 Nato by the Israeli's. They were a dime a dozen 20-30 years ago.
The barrel was shot out so I pulled it and found the receiver was set back to the third lug. So I screwed the barrel back in to check the original headspace and found it was still well within spec.
So that would indicate the setback occurred before it was rebarrelled to .308 and had not moved since. God knows how many shots it had through it but it had seen some hard use and the third lug had held it.
Ended up screwing a 30.06 barrel in and built my first custom on it, then after a few years I replaced the action and sold the rifle.
I kept that old Israeli as a specimen.

What makes the most sense is to ignore the safety lug completely; forget it is there. Making it contact accomplishes nothing.
And I have had a lot of the Israeli 308s; never had a receiver set back; they are usually well hardened if a bit rough on the outside.