how to fix a curved hole

oughtsix

oughtsix

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This is embarrassing. I need to fix an off center hole in a 26inch rifle barrel. The chamber end of the tube is well centered, but because I didn't use a pilot on my drill bit, the muzzle end is not centered. I have a barrel that curves on the inside from one end to the other.
I am thinking that if I mill or bore a larger hole on the muzzle end as far as I can and the same size hole from the chamber end, I could pull a very rigid bit/mill/reamer from one hole to the other and then I would have a larger, but straight hole to reline. This will, no doubt, be more expensive than buying a new barrel, but it is original to the rifle and I would like to salvage it, if possible.

Any one have experience straightening out log holes?

Thanks
 
I'm trying to get my head around why you drilled out the muzzle end? Anything that you do at this point is gonna make the barrel ID larger. I must be missing something from your post!
 
It's not uncommon for even a brand new barrel bore to have a slight curvature to it. What's more important is that the projectile leaves the end of the barrel bore consistently...ie; that it holds a tight group when fired at a target. If it holds a tight group, your sights can be adjusted accordingly.
 
The bit came through the muzzle end off center while drilling in preparation for a liner. I am proposing milling /boring a larger hole from both end to bring both holes back to center. if I had a rigid 13" bit or mill, I would go from each end and meet in the middle, don't have any thing like that, maybe purchasing one is the right option. my idea is once the two ends are concentric, the middle can be "straightened".

I will need a larger liner to fill in the new hole.

I don't know if this will work, that's why I'm asking

Hope that helps answer your question,



a slight curvature can be dealt with, this thing could shoot around corners. Plus I'd suffer much ridicule when my buddies see this thing. It's not a little off center.
 
Do you have experience doing this sort of thing? I don't but I have read a number of books on the subject so sorry If you already know this. Did you measure it before drilling possibly it was off to begin with. There are special tools for this kind of work did you use a standard twist drill? I believe tools are generally piloted off the old bore so it follows it. Is it curved or just off center if straight but off center the outside could be turned between centers and will match the bore. I don't think your idea of going from both ends would work as any tool that long will bend some. If the hole isn't curved too badly you could possibly try bending the barrel straight by sighting down the bore. I think it will be difficult to fix by drilling as it will most likely follow the curve.
 
As far as drilling the barrels out, yes, I've had previous success. Those barrels were in good shape to begin with. This was a rusted tube that was once a functional barrel. If the bore was curved before, it was not noticeable. It is now. and the barrel is straight., not going to try and bend it.
 
06, could you set it up on the lathe to bore the barrel straight, as deep as you can with a bar so that you know it is concentric. Then using a D bit continue down the hole, which hopefully will want to drill straight rather than follow the bent hole.

cheers Phil
 
Hello,
I would expect that anything you try to put down that bore will follow the curvature. To correct a shallow bore, you could use an end-mill to correct position, by using it as you would a drill.
 
elysianfield, yes that is the beginning, cut a flat hole with an end mill on each end then connect the two,


12bolts, didn't think of a D bit. Never used one, but that could be the answer to making the connection between the two squared up (as opposed to curved) holes.
 
12 Bolts is right on the way to 'straighten' the bore, but I'm curious as to how it got to be off center. If you bored the original barrel the bit, pilot or not should have followed the original bore. I've always used piloted bits for liner installation, but I can't imagine the bit getting that far off center from the bore. (A photo would help.)

I'm curious as to how this will work out. So please document the process and the results, good, bad or otherwise.
 
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