Significant Set Back/Rechamber

[Tumbleweed]

Hi all.
Looking for some educated opinions here. I have a 300RUM with only 350 rounds on it with a DE +P that that is 95% gone. It will need to be rechambered if possible, with a traditional lead this time.

Essentially I have 1- 1 1/8" freebore in this thing which will make it impossible for the reamer pilot to find and follow the lands even with lopping an inch off of the tenon first. I have heard from one local smith so far that feels very confident that the reamer will follow the old chamber and center up perfectly until the pilot finds the lands. Is this a big no no? If not, this barrel is junk. Thank you

 

[tobnpr]

First things first... what's the contour of your barrel? If it's a "lightish" contour where you'd end up with part of the chamber ahead of the barrel cylinder I wouldn't do it with that (or any other heavy magnum).

Gotta say "I don't know" insofar as possible chambering issues with the DE tapered throat. Your smith is correct in that the reamer (just like any other form cutter) will follow the existing hole, but personally I have concern of the unknown as to how the reamer might be influenced when the pilot does engage that oddball throat, and you need to clean up every bit of the original plus all of the erosion. So for me, I wouldn't do it simply because I'm not positive it can be done without issue. Maybe there's another smith on here that's been there, and done that.

 

[338 dude]

New barrel! On the negative side, a lot of things could happen with the chambering and you would still be putting it on a used barrel, although lightly used.on the plus side the only thing bad about a new barrel is the price!

 

[Tumbleweed]

New barrel! On the negative side, a lot of things could happen with the chambering and you would still be putting it on a used barrel, although lightly used.on the plus side the only thing bad about a new barrel is the price!

Price and wait time! This is still a "new" barrel and worth it to me rechamber if it can be done properly and precisely

First things first... what's the contour of your barrel? If it's a "lightish" contour where you'd end up with part of the chamber ahead of the barrel cylinder I wouldn't do it with that (or any other heavy magnum).

Gotta say "I don't know" insofar as possible chambering issues with the DE tapered throat. Your smith is correct in that the reamer (just like any other form cutter) will follow the existing hole, but personally I have concern of the unknown as to how the reamer might be influenced when the pilot does engage that oddball throat, and you need to clean up every bit of the original plus all of the erosion. So for me, I wouldn't do it simply because I'm not positive it can be done without issue. Maybe there's another smith on here that's been there, and done that.

It's a Bartlein heavy palma .9" at the muzzle and should have enough shank, no problem there.

 

[Bret GRAVELINE Graveline]

Once the smith has the barrel running true in the chuck and has it properly centered, providing he doesn't get in a hurry and forces things, the reamer will self center and will be fine,

 

[Lefty7mmstw]

ouch! I've had a solid 1/2 inch freebore on a 7rum, but 1 1/8 inch is a bit much... I wonder how she'd do with about a 225-250 hanging out as far as it can and a heap of powder for a 50bmg?

 

[338 dude]

Price and wait time! This is still a "new" barrel and worth it to me rechamber if it can be done properly and precisely

It's a Bartlein heavy palma .9" at the muzzle and should have enough shank, no problem there.

As long as the chambering or re-chambering goes well.

 

[Tumbleweed]

ouch! I've had a solid 1/2 inch freebore on a 7rum, but 1 1/8 inch is a bit much... I wonder how she'd do with about a 225-250 hanging out as far as it can and a heap of powder for a 50bmg?

Here's the issue, it still shoots in the .3's at 100 yards. The plus P went away pretty fast in the last 100 rounds and I have verified this with a bore camera and also l noted that my load has lost 50fps. It took 1.1 grains to bring it back up to its normal speed.

ES is now unacceptably high in the 40's where it used to be about 12. This is an ELR gun that I shoot to 2000 plus yards quite a bit. It will be a vertical stringer now at those distances. Probably ok at 1k. The overly long freebore is now causing uncontrollable ES. This us why it will need to be rechambered to suit my needs.

Also, I have used H50 in the past and it's a throat eater as bad or worse than N570.

 

[Lefty7mmstw]

I was thinking more along the lines of wc 872 or 867... possibly aa 8700 or us869 if you can find some. I'm running h50bmg in my 7rum (short throat) with a 175 now, but I'm running her mild enough that it isn't burning up that bad.
I'm running rl series in my 300rums; either rl33 or rl50 with 225's or rl25 with 180's. I wouldn't mind a bit more throat to get more rl50 in for a bit of extra cowbell (since it's at 3K with a 225 without pressuring out) but I don't want to be where you are with better than an inch.

 

[Tumbleweed]

I was thinking more along the lines of wc 872 or 867... possibly aa 8700 or us869 if you can find some. I'm running h50bmg in my 7rum (short throat) with a 175 now, but I'm running her mild enough that it isn't burning up that bad.
I'm running rl series in my 300rums; either rl33 or rl50 with 225's or rl25 with 180's. I wouldn't mind a bit more throat to get more rl50 in for a bit of extra cowbell (since it's at 3K with a 225 without pressuring out) but I don't want to be where you are with better than an inch.

This has had a steady diet of RL33 behind a 245. Did some recent testing with RL50 behind 250 Atips. Both of these combos run 3150fps out of 34"

 

[bigngreen]

Rechambers are hard on reamers, personally I wouldn't do them with my own reamers.
With a correctly aligned barrel you don't need a reamer bushing, reamer bushings are for starting a chamber, once the reamer is engaging the chamber it'll run to true center even if it has to bend to do so really a rechambers quality is about the smith.

 

[Tumbleweed]

Rechambers are hard on reamers, personally I wouldn't do them with my own reamers.
With a correctly aligned barrel you don't need a reamer bushing, reamer bushings are for starting a chamber, once the reamer is engaging the chamber it'll run to true center even if it has to bend to do so really a rechambers quality is about the smith.

Exactly what I needed to know. Thank you!

 

[Apex Custom Rifles]

I rarely do setbacks for one of many reasons. To do it right, it usually ends up being a little more work for the gunsmith than starting with a new barrel. It usually isn't cheaper ether unless they toss it in a steady a pray things will line up. At this point you are relying on the guy before you to have cut a perfect chamber and threads and the old chamber to line up perfectly with your new throat position if you're going to rely on that. Without measuring, and taking an arbitrary # like 1", you may end up with your new throat in a non-optimal spot (i.e. over a loose spot in the bore due to erosion). Not to say it won't work, just may not be its peak potential.

I personally wouldn't feel great about relying on the old chamber to "Find the lands" when a bushing engages. Many guys do it, I just choose not to waste time with it.

 

[Barehandlineman11]

Not worth it to save 500$ on a new steel barrel. Your still to pay your smith to do the work. I wouldn't +p it again either your taking a lot of barrel life away doing that.