Bad deal.
Broke my Mauser bolt shroud.
Must have had a hairline crack.
Just when everything was going well.
Dang

Interesting. Was it re-hardend after machining? If so, that is what caused it.

It looks to have failed at the forward edge of the horizontal cut made by a slitting saw. The slitting saw blade typically has alternating off set teeth to create a kerf, and the edges are very sharp leading to a sharp 90 degree corner. Perhaps putting a small radius in that corner would reduce the risk of this failure. I would be interested to know if that shroud was "heat treated" after machining. Obviously brittle, decarbonized steel from "burning" or hardened but not tempered steel might contribute to that failure.

I believe that is a Chapman kit, and I have only used Wisner's. Mr Wisner advised me to aneal, machine, then heat, quence and draw the 96 shroud but he stated the 98 had enough material and re heat treating was not needed. I wonder if Mr Wisner or any of the gunsmith's who install this kit frequently have seen this failure?

Of course the good news is the lever, spring and plunger look fine, and a surplus shroud is inexpensive. I bit of time on the mill and you will be good to go!

Ed: Oops, I was typing and dpcd beat me to it on the heating

That is why I asked; I have made many of these, and I never try to re heat treat them; they don't need it. I use a sharp cornered mill cutter too.
Whoever did this one didn't draw it back enough. Probably.

I'll agree also, don't think any of mine have ever broken like that. I have some made up if you need a replacement.

Don't know about the heat treat but it seemed pretty hard.

Jim, PM me and let me know how much you would need for a replacement.
I have some extra shrouds laying around so I could send one if need be.

The odd thing about this shroud was I had it done a few years ago for a bolt that had a swept back handle. Recently I decided to put it on another bolt so I could have a straight handle. Oddly, it wouldn't screw into any other bolt body. It was truly weird. It would start to screw in but stop. I measured every contact point I could and could not come up with a problem.

Likely your stop plumber; the one that keeps the bolt from opening when the safety is on, was out too far and didn't allow the shroud to turn in all the way in the other bolt. Fix is to shorten the plunger. It happens; tolerance stack up.

dcpd.
Thanks for the suggestion. Unfortunately it wouldn't screw in with the shroud stripped. That shroud would only work with one bolt body.
Several other shrouds screwed onto the bolt I was trying to use this one on with no problem.

Don't believe I've seen one split like that.

Steve.......

Looks to be a Mauser, they are a dime a dozen..so all is not lost.

You have a very sharp eye Ray!

A couple of things going on there.

Yes looks like the sleeve was reheat treated but not tempered back. So was hard not tough causing the fracture.

I have gotten to the point years ago that I simply temper all the M98 sleeves back to about 40 - 42 Rc and then use a carbide slitting saw, and use really good drills and taps. At that hardness the sleeve is tough but machinable, with little chance of breakage down the road.

Recently I picked up a bunch of M98 sleeves, almost 200 pieces, a hodge poge of Pre WW1 and Pre WW2 and some post war FN's. Those post war FN's have slightly different specs on the hollow mill cut and thread OD vs pitch. The FN sleeves will not thread into a Arg 1909 or CZ 24 bolt, HMMM.

I reset them up and had to recut the hollow mill cut on all those sleeves, they were from .005" to .010" undersize, and would rub on the OD of the rear of the bolts. OK so after recutting now about half would thread into the CZ bolt 1 - 2 turns.

I am now recutting the threads on those post war FN sleeves. Again they are oversize just enough to give the normal guy problems.

Could be that was one of those post war FN sleeves.

Jim Wisner