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How much to set back a barrel

SteveOak

SteveOak

Gold $$ Contributor
The barrel is fitted for a BAT S, SV, B, DS, 3L, 3LL and chambered for 6.5 PRC.

I want to use it on a BAT M. Would it be sufficient to cut the tenon off at the shoulder and thread it for a BAT M and rechamber it 6.5 PRC?

Thanks!
 
Physically just for the threads and shoulder yes, but if it’s a used barrel will that be enough for good rifling in the new throat area?
 
How many rounds are down the tube? That is the 64 dollar question.
For MR and LR prone shooting, I set bbls back a few rounds before the bbl is at 1/2 life. So a 6XC typically goes around 2200 -2400 rds total for me. I will set that bbl back at 1100 to 1300 rds. . I cut the tenon off n re-thread n chamber. That will get u into an area of the bbl that will provide a new, fresh leade. I will also cut 1/4 inch off the muzzle n re-crown.
Just my way n ymmv.
 
What's the profile of the barrel?
Chopping the tenon off and starting over isn't an issue with bull/varmint and straight taper type contours where there's plenty of shank/cylinder and meat ahead of it after you shorten it.
Sporter contours can be a problem- you don't want the chamber extending into a heavily tapered section.
 
Simply turn thread relief back .110" in length to establish a new shoulder. Recut cone and Ream to HS and run it. 1 thread equals .055 in length, so two will get you the needed length and index in same spot.
 
SteveOak said:
Straight 1.25"


Not exactly. Cutting the tenon off will not remove all of the chamber.

I think a 6.5 PRC reamer will completely clean up what remains of the existing (6.5 PRC) chamber.
Click to expand...
So, how many of these have you done, Steve? Cutting all of the threads off, even thought there is some of the old chamber left, is about like starting with a fresh blank. It still has to be dialed-in, and how much chamber you have left will determine where you get to dial. The barrel still has to be turned to proper length and threaded. Mostly, having existing chamber that you are going to enter with a reamer is not much different than drilling and pre-boring a 'fresh' blank. A re-chamber , as you suggest, cutting the threaded tenon off, may actually take more time than starting with new. And then there is being sure there's no carbon in the used barrel that will dull your reamer, before you ever put the barrel in the lathe.
 
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shortgrass said:
So, how many of these have you done, Steve? Cutting all of the threads off, even thought there is some of the old chamber left, is about like starting with a fresh blank. It still has to be dialed-in, and how much chamber you have left will determine where you get to dial. The barrel still has to be turned to proper length and threaded. Mostly, having existing chamber that you are going to enter with a reamer is not much different than drilling and pre-boring a 'fresh' blank. A re-chamber , as you suggest, cutting the threaded tenon off, may actually take more time than starting with new. And then there is being sure there's no carbon in the used barrel that will dull your reamer, before you ever put the barrel in the lathe.
Click to expand...

Exactly. Which is why it makes no sense IMO with a 1.25" bull to leave any of the original chamber. I'd sacrifice a little velocity and start "clean".
 
177 rounds a rechamber is totally worth it and I would go for it. Cutting just the tennon off will be fine if the original chamber was indicated good and can be indicated well a second time... otherwise cut the old chamber out completely and start again. I have rechambered a few, basically worn out barrels, and I will never do another one. Junk in is junk out IMO. Usually what I see is cheap people wanting to renew a barrel to some form of perfect and I have never had one yet that was worth my time. I work for free and dont do much work for others plus one or two builds for myself a year now.
 
Most know that I set barrels back on a regular basis.

However, the way I set barrels up in the first go round makes it very easy to set it back up to set it back.

What The OP is wanting to do will leave some of the original chamber. You have to be sure that this runs true with where the new throat will establish, keeping in mind that the reamer will try to follow what ever chamber is remaining. If that does not run dead true with the new established throat area, you might experience some problems, depending on how much runout is encountered.

If you do your own barrels, setting them back is definitely worth the effort. Of course, knowing exactly how to do it plays a big role in the decision to do it.
 
I made a video on the fitting of a Remington take-off barrel to a Winchester Model 70. The chamber on the Remington barrel, a 6.5 CM. was not all that straight (there's a shocker!). I had to set it back to straighten it up. Doing remedial work on something which is imperfect is sometimes more complicated that starting from scratch. Sometimes, there are compromises which must be made.
This is not at all like what Jackie does when he sets back one of his barrels. His barrel was chambered straight to start with and set up in a way which is easily repeatable. WH
 
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