Removing thread length on Tenon, pros and cons

[borderghost]

Just wondering if you have a .070 free bore and want to shorten it to a .025 free bore , is there any problem to just move shoulder forward , .040 or .050 thou , then redo tenon length and re chamber, then not having to try in pick up the existing thread , say on a BAT action that has a long tenon . Any safety or accuracy problems to do that. This would be for a 6 PPC bench rest gun , the barrels are not that long to began with. Just a question to more experience people . Thanks

 

[Alex Wheeler]

Thread tenon length has no bearing on accuracy.

 

[Fast14riot]

Basically, you wouldn't shorten the tenon if you move the shoulder forward that will lengthen it, then part it off back to the same length as before, but run a shorter free bore reamer? Just sounds like a normal barrel set back, but only a small amount.

 

[Lucky Shooter]

As you learn more about such things, you might consider getting a good rifle smith to do this.

This is simple stuff for them and they'll know the best approach----they won't have to try to
pick up existing threads, they'll just do it and move on-----quickly.

Wishing you success.

A. Weldy

 

[carlsbad]

If you're worried about losing .020 to .050 of thread engagement on the tenon as a safety issue that should generally not be a problem. some rifles (Weatherby comes to mind) have very short tenon threaded sections.

If you're only deepening the the chamber .050" and you're using a different reamer, you need to look at the prints and make sure the neck and shoulder dimensions match or the new reamer is bigger. You could end up with a hybrid chamber that might have problems.

--Jerry

 

[tobnpr]

In order to get the barrel timed the same (chambering stamp or other barrel markings), you'd need to shorten the breech by .625 and move the shoulder forward/deepen the chamber accordingly.

 

[carlsbad]

In order to get the barrel timed the same (chambering stamp or other barrel markings), you'd need to shorten the breech by .625 and move the shoulder forward/deepen the chamber accordingly.

You meant .0625

 

[Roeder]

You meant .0625

If it's a BAT as the OP alluded to, it would be more like .055

 

[TAJ45]

If a Bat, more like .05555...

 

[carlsbad]

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[ridgeway]

LOL. ^^^ The engineer version ^^^. No offense Jerry, lol

 

[TAJ45]

Couldn't sleep, eh Jerry? Hee hee
As measured w optical flats, iirc.

 

[338 Mollett]

You will be fine ,I did the same thing on some AR factory barrels with too much FB.The first 3 threads carry most of the weight.In my case the shank had 8 threads and I cut 2 off ,rechambered it ,installed the barrel nut good to go.

 

[tobnpr]

You meant .0625

Thanks... Pesky "zeros" lol...

 

[borderghost]

Thanks for all the information and reply's so far , I moved the shoulder forward about .060 and cut the tenon to length and re chambered with my .025 FB reamer , tried it out today and am pleased with the way it shot , maybe a little better then before or i just had a good day, ether way happy with outcome. Not sure if .060 would clean up the throat area that much to make a difference , it is a 3 lug BAT action.