Barrel set-back and rechamber

[Varmint Hunter]

I've got a custom 7 WSM that has about 1,000 rounds down the tube. While the accuracy hasn't fallen off all that much, it sure doesn't shoot like it did.
The barrel is currently 25". I'm considering having the barrel set-back and the chamber recut. Typically, how much barrel should I expect to loose; an inch?? More ?

 

[J E Custom]

I've got a custom 7 WSM that has about 1,000 rounds down the tub. While the accuracy hasn't fallen off all that much, it sure doesn't shoot like it did.
The barrel is currently 25". I'm considering having the barrel set-back and the chamber recut. Typically, how much barrel should I expect to loose; an inch?? More ?

Normally we set the barrel shoulder back one thread (1/16th) and recut the chamber. it cleans everything up and saves as much barrel as possible. It also cleans up the lead angle and the throat.

The barrel tenon will have to be shortened by the same amount.

J E CUSTOM

 

[shortgrass]

A bore scope examination, by an experienced eye, should give you a good Idea how much to take off. I re-chambered a 6.5mm X .300RUM to .264 Win. Mag. and had enough shank that I cut off 1 1/8". That came real close to getting back to decent rifling........... One turn may not be enough, 1 1/8" may be more than needs to be removed. Bore scope it. How much shank do you have now?

 

[BountyHunter]

The 7 wsm is noted for being hot. You could easily have firecracking up well more than 1 inch.

Only way to tell is a good bore scope investigstion.

Plus IMO to are already below optimal barrel for a 7 wsm. I would want a MI imum of 26 inches.

 

[Varmint Hunter]

The 25" may not be optimal but on a hunting rifle its about as far as I want to go. I use the rifle in box blinds and other confining stands. I actually ordered the 25" finished length with the idea that I could set the barrel back once before considering a rebarrel.
Even though it is primarily a hunting rifle, I shoot it a lot.

Just might rechamber to 7-300WSM because of the brass issue.

I also had a .308 win built with the idea that it would be unlikely for me to shoot out the barrel. I was right on that one because I like shooting the fast steppers much better.

Thanks for the replys.

 

[BountyHunter]

Check the bore as I have seen firecracking 3-4 inches on hotter loads. You do not want to rechamber unless you can cut all that off and still have enough good barrel and shank.

 

[J E Custom]

The 25" may not be optimal but on a hunting rifle its about as far as I want to go. I use the rifle in box blinds and other confining stands. I actually ordered the 25" finished length with the idea that I could set the barrel back once before considering a rebarrel.
Even though it is primarily a hunting rifle, I shoot it a lot.

Just might rechamber to 7-300WSM because of the brass issue.

I also had a .308 win built with the idea that it would be unlikely for me to shoot out the barrel. I was right on that one because I like shooting the fast steppers much better.

Thanks for the replys.

With only 1000 rounds through the barrel you should be ok, But as BH said, be sure and check it
before you start. If you fired it many times in rapid succession and the barrel got hot, it may have
to be replaced. If it looks ok, the 1/16th (One thread) will clean it up without cutting the barrel shank and shortening the barrel 3/4 + Inches.

If you change to a 7mmx300 you will have to cut to much of the chamber out to do a 1/16th set back because the cartridge is shorter. If you re barrel, then it would not be a problem.

The cost of setting the chamber back should be a lot less but a barrel change might be the best move in the long run.

I agree with you about barrel length of the 7 WSM It should be at least 23" to 24" to keep from giving up to much.

J E CUSTOM

 

[Trickymissfit]

I've done it several times on personal rifles, and I sort of have a rule that I want to at least remove the neck length plus another .06" minimum. Still that's just me. Yet a lot of a barrel set back has to do with the chamber quality as well as throat damage. I had a Remington that I ended up cutting 2.75" off the big end just to get a good chamber. On the other side of the coin, I did a barrel set back on a Savage 22-250. I shot a lot of 3031 thru that barrel plus some others that tend to burn pretty hot. I ended up doing about .40" to get to virgin metal. Just varies per rifle, so start out with a good bore scope job, and maybe even a chamber cast.
gary

 

[Varmint Hunter]

Thanks for all the feedback. It looks like the answer lies within the borescope. As soon as the hunting season is over I'll bring it to my gunsmith for an evaluation.

I never really shot it hot but book max loads were regularly fired throughout years of testing various bullets. It shot great with 180 VLDs for some time but now shoots much better with plain jane 160 Accubonds. My guess would be that the throat geometry changed. We'll see.

 

[lazylabs]

I dont see the return on investment. If your paying 75% of fitting a new barrel with short life and possibly not great groups... I would just go with a new barrel.