Changing POI in SxS

[pacanis]

Lets say that my Pietta percussion 12ga does not shoot where I point it. One barrel shoots right and one barrel shoots low. Enough to where I want to regulate the barrels to get them at least closer to hitting where I want.

I've done some internet searching and there are ways to accomplish this by reshaping the muzzle. One guy even mentioned that a muzzleloader who shoots skeet with him did his gun right there on the spot. Specifically I am reading to slightly chamfer the inside of the muzzle. But unfortunately the threads I am finding across a few different forums are split 50/50 on where the chamfer should be placed to move the shot in what direction...

The shooter above said the ML guy put a chamfer inside his muzzle on the Bottom to move his shot Up. And it worked perfectly. And others agreed.
Then there is the other 50% who said it was backwards. That if you want to move the shot up you should chamfer the top...
Y'all know how these threads go. Then there was the other 50% who said to send the gun back or send it to a smith and have him break the solder to the rib and regulate the barrels.

So... in an effort to see if anyone here has done this before or seen it done... just where do you place the chamfer to move the shot in what direction?
Maybe by some stroke of remarkable luck there will be an agreement. At least it will be replies from members I've gotten to know somewhat, so I can more easily separate fact from fiction.

 

[French Colonial]

Lets say that my Pietta percussion 12ga does not shoot where I point it. One barrel shoots right and one barrel shoots low. Enough to where I want to regulate the barrels to get them at least closer to hitting where I want.

I've done some internet searching and there are ways to accomplish this by reshaping the muzzle. One guy even mentioned that a muzzleloader who shoots skeet with him did his gun right there on the spot. Specifically I am reading to slightly chamfer the inside of the muzzle. But unfortunately the threads I am finding across a few different forums are split 50/50 on where the chamfer should be placed to move the shot in what direction...

The shooter above said the ML guy put a chamfer inside his muzzle on the Bottom to move his shot Up. And it worked perfectly. And others agreed.
Then there is the other 50% who said it was backwards. That if you want to move the shot up you should chamfer the top...
Y'all know how these threads go. Then there was the other 50% who said to send the gun back or send it to a smith and have him break the solder to the rib and regulate the barrels.

So... in an effort to see if anyone here has done this before or seen it done... just where do you place the chamfer to move the shot in what direction?
Maybe by some stroke of remarkable luck there will be an agreement. At least it will be replies from members I've gotten to know somewhat, so I can more easily separate fact from fiction.

The shooter above said the ML guy put a chamfer inside his muzzle on the Bottom to move his shot Up.

This is correct, the "chamfer" as you call it allows gas to escape along that area and forces the ball/shot charge in the opposite direction.

I believe Britsmoothy has experience with this method if he cares to opine.

 

[pacanis]

This is correct, the "chamfer" as you call it allows gas to escape along that area and forces the ball/shot charge in the opposite direction.

I believe Britsmoothy has experience with this method if he cares to opine.

Thanks.
Chamfer was what I saw it referred to. I imagine it could also be called a bevel, or a relief.
Whatever term that means removing metal at an angle at the muzzle.

 

[Brokennock]

@Britsmoothy and a couple others here have hands on experience with this.
The skeet shooter example is correct. If you want to shoot higher, say towards noon, file at 06:00. Want to shoot more towards 2:00, file at 8:00 , shoot more towards 4:00, file at 10:00.
I think the confusion comes from referring to right and left as it relates to facing the muzzle to work on it or the direction the muzzle is pointed in.

 

[pacanis]

Thanks Brokennock.

It seemed the "two sides" had one side saying the gasses escaped the bottom quicker and pushed the payload in the opposite direction (up in this case)... and the other side said the gasses should be behind the payload and the shot would favor the side where the chamfer was. So if the chamfer was on the bottom that is the direction you were moving things.

I hate when there are two sides, lol.

 

[Brokennock]

Thanks Brokennock.

It seemed the "two sides" had one side saying the gasses escaped the bottom quicker and pushed the payload in the opposite direction (up in this case)... and the other side said the gasses should be behind the payload and the shot would favor the side where the chamfer was. So if the chamfer was on the bottom that is the direction you were moving things.

I hate when there are two sides, lol.

Yeah, especially when both sides have some logical reasoning behind them. The gas push is how I understand it, but I am always happy to be be proven wrong,,,, emphasis on proven. I do like me some supporting evidence, should have been a lawyer or scientist.....
Two sides is much easier when it is a matter of clear cut right and wrong.

 

[Sparkitoff]

How much right and low? Making an oblong muzzle isn't really the correct way to accomplish regulation, and it is hit or miss at best.

 

[Trigger]

I wouldn't use it. Probably sell it and get something hopelly shooting center.

I spent good money. I'd be pissed If had that problem.

Depending how far off the barrels are and at what range where is noticed... it's no good.

 

[Britsmoothy]

As described does indeed work and it won't be " oblong". The amount remove is miniscule and barely visible to the eye.

It was also a correct way to "regulate" a shotgun. I've seen many old English doubles with shaped muzzles.

With thin wall muzzles, rather than bevel the barrel actually file the barrel away. Only .020"-.030" at a time and test.

I once just took a file to the field and a roll of wall paper. One hour later it was done.
On returning home I polished the file marks away and called it good, and good it was!

 

[Flint62Smoothie]

If shooting low ... can't one add something to the comb too? As an option?

 

[pacanis]

With thin wall muzzles, rather than bevel the barrel actually file the barrel away.

Thanks for the first hand information.

To clarify, Do you mean
... rather than bevel the [inside] of the barrel, actually file the barrel away [meaning create an angle at the whole muzzle]

The first thing I did before asking here was angle the entire muzzle. I took about 0.040" off the right side of the right barrel (the barrel shooting left) and it angled it towards the rib.
No difference.

Then, leaving that angle there, I beveled/chamfered the inside of the rib side of the right barrel.
That moved the group a couple more inches left. I shot again and had one 00 buck pattern on top of the first.
So in reality, the inside chamfer pulled the shot in that direction rather than pushing it in the opposite. But it already had that angle at the muzzle.

So which way is it?
The inside bevel will push the shot to the opposite side? My inside bevel seemed to have the opposite effect.

FWIW I am shooting at 15yds and the right barrel hits 4-5" left of where I am aiming and the left barrels hits 3-4" below.

 

[pacanis]

To put that in a relatable situation.
If there was a rabid skunk 15yds in front of me, in all reality I'd only make it mad.

 

[pacanis]

If shooting low ... can't one add something to the comb too? As an option?

There are ways to adjust your sight picture to get you hits on target. Pitch it's called.
Slow deliberate shooting I've always been of the mind set that the aim points should be true.
If both barrels hit low but the windage was good I wouldn't give it a second thought and adjust for it. Put a smaller bead on even.

 

[rickpa]

V.M. Starrr was an old smoothbore shooter back in the 60s and 70s. See if you can find some of his writings. Max Vickery used to write smoothbore articles in Muzzle Blasts also. These men were experts with smoothbores.

 

[pacanis]

V.M. Starrr was an old smoothbore shooter back in the 60s and 70s. See if you can find some of his writings. Max Vickery used to write smoothbore articles in Muzzle Blasts also. These men were experts with smoothbores.

Thanks. Maybe I can find what they say.

 

[Mike in FL]

As described does indeed work and it won't be " oblong". The amount remove is miniscule and barely visible to the eye.

It was also a correct way to "regulate" a shotgun. I've seen many old English doubles with shaped muzzles.

With thin wall muzzles, rather than bevel the barrel actually file the barrel away. Only .020"-.030" at a time and test.

I once just took a file to the field and a roll of wall paper. One hour later it was done.
On returning home I polished the file marks away and called it good, and good it was!
View attachment 256528

Now that is a pretty photo!

 

[bigted]

I can make a case in my mind both ways so I am watching this thread closely.

I would consider Britt’s to be an expert here as well and value his opinion.

lastly wonder idly what is the “gift upgrade” I see under folks name on the left?

 

[Britsmoothy]

I'm no expert I simply read about it and tried it.
One double muzzloader. Two double breech loaders and one single barreled muzzloader all responded. I have also bent other single barrel muzzloaders and single barreled breech loaders.
I've also bent the stock on one gun but don't fancy that again!!

 

[Britsmoothy]

Thanks for the first hand information.

To clarify, Do you mean
... rather than bevel the [inside] of the barrel, actually file the barrel away [meaning create an angle at the whole muzzle]

The first thing I did before asking here was angle the entire muzzle. I took about 0.040" off the right side of the right barrel (the barrel shooting left) and it angled it towards the rib.
No difference.

Then, leaving that angle there, I beveled/chamfered the inside of the rib side of the right barrel.
That moved the group a couple more inches left. I shot again and had one 00 buck pattern on top of the first.
So in reality, the inside chamfer pulled the shot in that direction rather than pushing it in the opposite. But it already had that angle at the muzzle.

So which way is it?
The inside bevel will push the shot to the opposite side? My inside bevel seemed to have the opposite effect.

FWIW I am shooting at 15yds and the right barrel hits 4-5" left of where I am aiming and the left barrels hits 3-4" below.

Filing all the way across may of been to much.
I guess the bevel although on the wrong side was undoing the fact you had filed all the way across.
I never go any further than half way, or half the diameter.

Did you say it's multi choked?? I have no experience in adjusting multi chokes this way.

 

[pacanis]

Filing all the way across may of been to much.
I guess the bevel although on the wrong side was undoing the fact you had filed all the way across.
I never go any further than half way, or half the diameter.

Did you say it's multi choked?? I have no experience in adjusting multi chokes this way.

Let me ask it this way:
Looking down on the barrel, as in top view:

If I file barrel A as shown across the muzzle, which way will I move the pattern?

If I bevel the INSIDE of barrel B halfway around on the side circled, which way will the pattern move?

Thanks

oops! Forgot to add the pics, lol.