Reboring cop-out

21 November 2003, 17:49

Pete Millan

Reboring cop-out

Some history:

My 22-250 with 1:10 twist is nigh on shot out after 17 years of service. It is a McGowan heavy sporter barrel, mounted on a Sako AII.

I gets to thinking, can I re-bore the barrel to 6mm, and rechamber in 243?

I phone Truvelo, the local barrel makers and explain the situation quite clearly. Their top tech says no way can it be done because the existing 1:10 twist is too tight for the 243.

Huuuuuunh? I'm thinking WTF is this guy saying? Surely they rebore the barrel out to a new dimension before applying the button?

Have these guys copped out of reboring with a silly fartarse excuse, or is a 223 bore too close to a 243 for reboring?

22 November 2003, 01:59

mbogo375

Pete,

The guy did not know what he was talking about. This would be an easy rebore.

Jim

22 November 2003, 02:18

bluetick

Pete

Not sure about a rebore I know nothing about the procedure. I would just like to suggest the 250 Savage. It is every thing the 243 wants to be.
Plus if you have 17 years worth of 22-250 brass you should have no worries there either.

Good luck and God Bless
Shawn

22 November 2003, 02:44

tiggertate

223 to 243 is pretty close to the minimum the LaBounty will work with. I wanted a 270 taken to 284 and he said there was insufficient metal to guide the reamer and it would chatter. You are only .006 more. Besides that, a good rebore runs around $200 with no other work so the economics lean toward a new barrel, all else being equal. Having said all that, the twist issue sure sounds like a red herring.

[ 11-21-2003, 17:45: Message edited by: tiggertate ]

22 November 2003, 11:05

mbogo375

quote:
Originally posted by tiggertate:
223 to 243 is pretty close to the minimum the LaBounty will work with. I wanted a 270 taken to 284 and he said there was insufficient metal to guide the reamer and it would chatter. You are only .006 more. Besides that, a good rebore runs around $200 with no other work so the economics lean toward a new barrel, all else being equal. Having said all that, the twist issue sure sounds like a red herring.

Actually you need a bore diameter on the new caliber that is somewhat larger than groove diameter on the old caliber to completely clean things up. Figure that groove diameter is usually not more than .010 more than bore diameter. Add .002-.006 to that (total of .012-.016) and if the barrel was not deeply pitted it should work pretty well. In your example you were only dealing with a .007 difference (.277 to .284). I can understand why Cliff was hesitant about this. In the case of 223 to 243 you would actually be dealing with a difference of .019 (.224 to .243). This should clean up fairly easily.

You are right about a new barrel probably being a better way to go [Smile]

. The exception, of course, would be exterior features of the barrel that might make it worth the effort of saving (sights, ribs, prestigious makers name, etc). There is always at least a slight risk that a rebore won't work out (some steels work better than others, and then you may also expose hidden flaws in the metal that were not previously at surface level), and then you would have to rebarrel anyway.

Jim

22 November 2003, 11:09

tiggertate

Thanks for fixin' my math... I never did work a pencil well!

22 November 2003, 13:52

J Wisner

I'll jump into this since no one who has operated a reboring and rifling machine has stepped in yet.

It depends upon the barrel.

It depends upon the type of the reamer you are using.

It depends upon the type of oil and the condition of your machine.

You may or maynot be able to rebore from 224 to 243. Due to chatter in the reamer. Going to 257 is a safe one though.

James Wisner

22 November 2003, 15:49

Bill Leeper

Also, rebored barrels must be cut rifled. You cannot button an already tapered barrel. Reboring is becoming a bit of a lost art. Regards, Bill.

22 November 2003, 16:50

mbogo375

quote:
Originally posted by J Wisner:
I'll jump into this since no one who has operated a reboring and rifling machine has stepped in yet.

It depends upon the barrel.

It depends upon the type of the reamer you are using.

It depends upon the type of oil and the condition of your machine.

You may or maynot be able to rebore from 224 to 243. Due to chatter in the reamer. Going to 257 is a safe one though.

James Wisner

Since I assume that your post was directed at me I will absolutely agree that you are right. I have never operated a reboring and rifling machine. I have had rebores done down to as little as .010 difference in groove diameters (the lands were only .008 deep in the original however, so there was a .002 margin between the old bore diameter and new groove diameter). When dealing with very tight tolerences and other variables such as hardness and homogeneity of the steel, as you rightly pointed out, sometimes it works and sometimes it doesn't, even with the best equipment and most experienced craftsmen (or should I say artisans, since reboring seems to be more of an art than a science). I was only relaying the information that I have been told over the years by people who specialize in reboring, and who I have had work done by. I respect their opinions, and I respect your opinion. It was not my intention to intimate that I have done any reboring myself, but then I assume that your statement was more to cast aspersions on the information that I presented than my experience.

Jim

22 November 2003, 17:05

J Wisner

Mobogo 375

I did not mean to insinuate that anyones information was incorrect.

There are so many VARIABLES that it will give a person gray hair and cause one to drink something other than good whiskey.

I operated one reboring and rifling machine for several years, long enough to know that I did not want to do this for the rest of my lifetime. So went off and started machining steel gun parts instead.

Yes, reboring and rifling is a True Art Form.

James Wisner

[ 11-22-2003, 08:47: Message edited by: J Wisner ]

26 November 2003, 03:47

Pete Millan

Guys, thanks for the input. These blokes only do button rifling and as the barrel is already tapered I guess a rebore is out.

Cheers

pete

26 November 2003, 09:34

Brent Moffitt

While we're on the subject, I've got a Ruger Magnum in 416 and have thought of reboring it to .510 to shoot the big 50 bullets from the 408 CheyTac case (strengthened 505 Gibbs basically).

If I did this, I'd like to see the rifle look the same as it does, rib and sights, beddding setup etc, so a rebore has always been in my mind. I see Hamilton Bowen will rebore convert them to 505 Gibbs.

It may be less expensive to do this barrel than rebarrel, considering the recoil lug arangement and sights etc.

I believe it's a hammer forged barrel too.

Cryo treat it afterward??

Any concerns or reason for avoiding the whole idea?

26 November 2003, 09:55

tiggertate

Call the reborer you intend to use and ask.. they may or may not work on certain brand barrels based upon their experience. Otherwise you're probably correct in that this is the sort of barrel where the economics break toward reboring. As I recall, LaBounty rebores the Ruger barrels for Bowen. He also rebores the Ruger pistol barrels for Tom Griffin's Linebaugh Redhawk conversions so your Ruger project should be doable; just don't be in a hurry. Turn-around times are long because of the nature of the work.

[ 11-26-2003, 00:56: Message edited by: tiggertate ]