[Lucky Shooter]

I have a dusty old 700 action that's begging for a barrel.

I know how to make the measurements for fitting and chambering the barrel but would appreciate some practical limits on the clearance between the bolt nose and the counterbore.

My thinking might be wrong but I like the idea of minimum practical clearance between the bolt nose and the counterbore------minimum amount of cartridge case that is unsupported in the web area.

I realize the counterbore is a natural place for powder, lube and whatever to accumulate------it isn't a very easy place to wipe clean and assume most of the clearance is to allow for this.

Any opinions on how little clearnce I can live with ?

Thanks.

A. Weldy

 

[vmthtr in green bay]

I used to have a set of prints for the different actions, and seem to remember .010" for that measurement. Hope someone with more knowledge or something in writing helps you out.

Mike

 

[Jim in Idaho]

Allan, I've got a 22-250 that was barreled by Shilen. I measured the bolt recess and it shows .700". The outside of the bolt measures .695". I'll try and geta measurement off my .270, which is a factory-barreled rifle.

 

[Jim in Idaho]

.270 shows a recess of .704", and the bolt measures, at its widest point, .694"

 

[Lucky Shooter]

Thanks for replies

Mike, I've seen the .010" clearance kicked around and wonder if it possibly came from a "cookbook" set of instructions that were set up with loose enough tolerances to work on any 700 action. I'm looking into the practicality of a more custom fit, based on measurements off the specific action.

Howdy Jim, sounds like I didn't do a good job in describing what I was looking for. What I was looking for is the clearance between the end face of the bolt, square to the bore------and the bottom face of the counterbore, also square to the bore. I don't know of a simple and direct way to measure this but think I can set it to a desired number, based on action measurements.

This is a winter time deal. If I don't get it done before warm weather, it'll probably get put off until next winter.

My guess is that this crowd will eventually provide an answer for me to work to.

A. Weldy

 

[James in]

Doug Shilen said .005 end clearance is what they use.

 

[Jim in Idaho]

OK...I was thinking the side clearance between the counterbore and the bolt. I'll try and get the correct dimension, if I can.

 

[keithcandler]

Alan, custom guns are usually set up a .005......

I would think that 0.010 would be ok, but kinda on the long side for a custom gun.

 

[kaferhaus]

I use .005 on both the recess and and breech to lugs, for "target rifles" and .010 on hunting rifles.

 

[Lucky Shooter]

More thanks to James, Keith and Steve

I can see now that reducing normal clearance even more won't make much difference in the percentage of case web that's directly supported by the chamber.

Scratch this idea.

Thanks again to all.

A. Weldy