Mr. Belk,

A while back you posted this response to someone's question, "Too many people "lap lugs" without first making the action ready to lap. On any split lug action the recesses need to be lapped before the bolt, otherwise you can't properly check headspace."

Can you please elaborate? I understand the recess lapping tool you showed a pic of but wanted to know how you finish the lapping job once the recesses are trued.

Thanks,

Mike

Mike--

This is an old post that may answer the questions. Let me know if it doesn't.

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Repost--

The process should be to apply an even pressure against the face of the bolt in line with the bore while rotating the bolt. This is usually done by a dowel that runs through an old section of barrel and pressure applied by hand or a compression spring if you get fancy.

Lapping lugs does two things; First it makes more steel to steel contact for better transfer of energy from the bolt to receiver. It makes racing slicks out of street tires. It also cuts away the little ripple that forms as the metal flows from pressure. Mausers will have one where the split lug seats, too. When working on Mausers we can assume the action has been fired several if not many, times. The result of this firing is a very slight "dishing" of the locking lug recesses where the lugs bear against it during firing. When more than a couple thousandths its called "set-back". It’s where excess headspace comes from.

The problem is that by “reading” contact on the lugs by looking at the lugs doesn’t work. That pattern on the lugs is a “wipe” pattern, not a contact indicator. Only if there is a smoothly lapped surface inside the receiver does it mean there is good contact.

Anytime I see opposing corners contact I think the bolt is crooked in the action. That can be caused by pulling on the bolt handle as its lapped. All the pressure should be from straight ahead. You need a guide for that. Old military barrels make excellent guides.
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Thanks Mr. Belk,

It sounds like, if I'm understanding this correctly, that once you've used your recess lapping tool, then you switch to using the bolt and the stub to mate the lugs & recesses.

I thought that after truing the recesses you might have trued the lugs in a lathe. And then done a final lapping as you described. That's where my confusion came from.

I appreciate your time and effort in answering what must be tedious questions for you.

Thanks again.

Z1r---

To take trueing in the lathe would take an action so incredibly poorly made as to not make it past the initial inspection and then richochet off the garbage can!!

I've NEVER seen a M-98 that was more than a few ten-thousandths out of square. A really poor Rug-Rem-chester will be .002 out of whack.....which is a BUNCH. It might take 5 minutes with a diamond lap to repair, but never a lathe.

The problem is NOT with the lugs offset on the bolt, (unless it's a 77/22Hornet which is pure junk to begin with). The real problem is with badly machined surface on the engagement surfaces of the recesses and rear of the locking lugs. The street tire to racing slick analogy is a good one. THAT'S what lapping helps.

To demonstrate how close most lugs are to being right use a piece of the clearance measuring plastic, Plasti-guage I think they call it, at the auto parts store. Put a strip in each lug recess and exert about a hundred pounds of pressure squarely agains the bolt face. Measure the Plasti-guage.

The bottom line is this: If locking lugs have been lapped with the barrel on the action the chances are 99 to 1 the action is SCREWED UP!! It *might* be repairable by refacing on the lathe. Some aren't.

Thanks Again!!

All clear now!