Muzzle filing to adjust POI

Correct , the Guy that did mine took it past the point he thought was required so after the spring back it was correct..

It took two times too get it right but it’s dead on if I do my part…

Kansas Kid said:

If I get an opportunity I’ll try the full gangster tilt this weekend.

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Your sights are set to account for the gravitational pull on the ball from a vertically held gun. if you turn the gun on its side, the correction no longer works, and you will shoot low and to one side or the other (depending on which way you rotate the gun)

Kansas Kid said:

Tried that once already as it looked offset so removed it and re solder it at 12:00. I’m not a quitter.
I liked putting it in my large lathe and pulling the barrel and using a center in the tailstock to measure progress. So I’m back to bending.
Sounds reasonable about not being able to steer a round ball.
Also have heard the theory of a thin barrel will shoot it’s self back to where it was after bending. I almost swear that’s what happened on my first bending trials as the first few shots were good then it seemed to go back to where it was.

I’ve owned and or built probably a dozen smooth bores and this one is a challenge.

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Kansas Kid said:

Yes. I also made a plug with a small center hole that fits close in the muzzle. You can put fishing line through the hole and then run the string down the top of barrel to center of tang and tell how straight or not the barrel is. I worked in a machine shop 35 years or better. And have straightened a few things over the years. This one is just being stubborn

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Just kind of refreshing where I sprung the barrel before and am somewhat versed in metal working. I’ll make another go of it soon and hopefully it stays put.

Steve Martin said:

I had a very similar issue last year with my Fusil de Chasse. Turns out it was a combination of TWO issues. My barrel was actually bent but I was able to correct it a good bit myself using a large drill press I rigged up. That took three careful bending sessions (with a long trip out to the range after each session on the drill press to check my progress). However, still wasn't shooting quite true to POI so I took the gun to a gunsmith and he discovered the muzzle was not true to the bore. Once that was corrected it shoots great, right to POI. I am now very pleased with the gun so don't give up on it yet!

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Define “true to the bore”?

If you bend a barrel to straighten it , that is one thing . If you bend a straight barrel to sight it in at a specific distance , that is quite another thing , the gun will only be sighted in at that distance alone and will still be off at other distances

Kansas Kid said:

38” thin wall barrel LH NW trade gun .24ga. Done with trying barrel bending to correct windage problem. .550 ball .018 patch 55gr 3f. Shooting at 35 yards it groups good and consistent. Problem is at that range it shoots 12” to the left. So going to try filing the muzzle at an angle. I assume I need to file on the left side to steer the ball to the right? And about how much do you think would need to be removed in degrees?

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I have a 45 caliber rifle that the right thing had Corroded Most of the rifling off of one side Of the muzzle, And I filed the opposite side and fixed my rifle that shot 8 inches to the side. I don't how that would work in a smooth bore. I really doubt that it would, Have you considered just cutting an inch or so off the barrel and see if that would straighten it out? Barrel bending Kind of gives me the heebie-jeebies. I would maybe attempt it, but very cautiously
. Squint

bud in pa said:

Having worked in a machine shop years ago, one of my jobs was to straighten parts that were hardened to 60 Rockwell. I was using a 50 Ton Press. You had to past center to straighten them and not have them spring back to their original shape. The amount of bend was different on each one.

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Some kind of stress relieving might be in order after bending. Cryo-treatment might work, but that might add too much to the cost.
There must be other methods that could be done in a home shop.

This is what I have done:
When I have bent/straightened a few barrels in the past, when I got to the point that I was doing what must be the final bend, I would put another stress load on it, and walk away, leaving the load on it for at least an hour. When I came back I would take a lightweight rawhide headed mallet and rapidly tap it with some force all over on all sides, end to end in an effort to relieve some of the stress. Maybe 400 to 500 blows at about 3 to 4 hits per second. Sharp strikes, but not nearly hard enough to dent the barrel.
At least that was my method. Don’t know if the tapping helped, but to my knowledge none of the barrels I used this method on ever reverted to their previous state, even when hot from rapid shooting.

I would like very much for someone like Dave Person or anyone with good knowledge of metallurgy to read my method and comment as to whether it has any merit.

I got it used years ago and don’t know the exact alloy of the barrel so not going to guess wether normalizing in a a furnace or anealing would do it any good. If I still had my shop I’d try driving a bore size mandrel down it and shot peen the outside

chorizo said:

Try this...LOL

This must be massively frustrating, especially with a gun you like.
View attachment 167603

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I want to see the ramrod used after this bending operation.

Update. I bent it again last week and went to the range to try it out. Over bent it and it shot to the right. Took the barrel out at the range and laid it across a bench and pretty much done a CPR palm on it to take some spring out. Now hitting good at 20 to 50 yards. Shot a woods walk Rendezvous last weekend and two of the shots were behind a simulated fort so was ok to rest off of logs. Hit dead center still, so real happy with old cross eyed Jack now.