Rem tenon dimensions---check

[Lucky Shooter]

I want to set up a Rem tenon to provide .005" clearance between Breech Face and Bolt Lugs and .005" clearance between Bolt Nose and the end of the counterbore.

I've taken the following measurements from the receiver, bolt and recoil lug:
Bolt Nose to Bolt Face---.150"
Bolt Nose to Bolt Lug----.152"
Action Face to Bolt Nose---.539"
Action Face to Bolt Face---.689"
Recoil Lug Thickness---.185"

How long should the tenon be with the specified clearances and measured dimensions ?

What should the Counterbore Depth be ?

Where would the Bolt Face be----relative to the Breech Face---under these conditions ?

I'd like to see what other folks come up with for these numbers. I've tried to put this into an Excel Spreadsheet and have gotten the following numbers:

Tenon Length---.871"
Counterbore Depth---.152"
Bolt Face would be .003" outside the Breech Face

An observation is that----if both clearances are equal---the Counterbore Depth should be the measurement from the Bolt Nose to Bolt Lug, no arithmetic needed for this.

If anybody has the time and inclination, I'd appreciate seeing your numbers.

A. Weldy

 

[Dennis Sorensen]

If you machine the tenon 5 thou less than the receiver face to bolt lugs you will have about 3 thou clearance when it is torqued tight... so allow 2 thou for that and machine the tenon 7 thou less... then simply counter bore the bolt nose to lug measurement and that clearance is already there...

Unless I am missing something? Is this a trick question?

 

[wnroscoe]

If you machine the tenon 5 thou less than the receiver face to bolt lugs you will have about 3 thou clearance when it is torqued tight... so allow 2 thou for that and machine the tenon 7 thou less... then simply counter bore the bolt nose to lug measurement and that clearance is already there...

Unless I am missing something? Is this a trick question?

Wouldn’t you have to also add the lug thickness to this?

I've found that after taking all my measurements and allowing for clearance between the front of the bolt lugs and breach I just cut the bolt nose recess what ever it measured, the clearance is already built in. In this case I'd cut the tennon length to .870"

Recoil Lug thickness .185" + Bolt Nose to Bolt Lug .152" + Action Face to Bolt Nose .539" = .876" using your measurements. I deduct .006" for mine, this would leave a tennon length of .870"

Cut your Bolt Nose Recess .152" deep, there's .006" clearance built in already.

 

[Lucky Shooter]

Dennis----no trick question

After reading some posts here and talking to a few other people, it seems that some thought minimum clearances should be around .005".

My intent is to guarantee these specified clearances and to minimize the amount of unsupported case head.

I prefer to start with actual measurements and do whatever numbers are necessary to arrive at the final dimensions.

The use of Excel minimizes mistakes in arithmetic and provides a stored record for later use with the particular rifle.

I want a simple and consistent method. Thanks for your reply.

A. Weldy

 

[Dennis Sorensen]

Wouldn’t you have to also add the lug thickness to this?

I always treat the lug as part of the action and it is in place when I do my measurements...

Every action can be different. My first measurement is from the front of the lug on the action to the front of the lugs an a closed bolt. I allow 2 thou compression for tightening... and add the clearance I want.

My next measurement is from bolt nose to bolt lugs. That is how much I cut the recess.

My next measurement is from the front of the action with the recoil lug in place to the face of the closed bolt. I allow 2 thou compression for tightening. This is go gauge measurement when chambering.

After chambering to these specs it will be assembled and checked with the go gauge and if small adjustments are required I do them.

Of often I will chamber first and then work to my measurements from there.