Gun don't shoot

[Rawhide67]

I'll preface this by saying I've not shot this gun. But, custom built 54 flintlock, Cochran lock, Colerain barrel, round bottom rifling. Owner sent it home with me to disassemble and check for tight spot in the barrel channel or anything that might be wrong with the barrel.

Owner bought it in the 80's, said he couldn't get enough windage to get the gun on paper at 50yds. Sold it years ago. Just bought it back for the guy he sold it to who told him, can't get it on paper at 50yds, about 12 inches to the left of bullseye is the best he could do.
I took the gun apart and found the barrel was bedded. There are no wear marks on the browned finish indicating a high spot in the wood. In my mind it would take alot of pressure to impact accuracy like that. Barrel appears straight. Bore looks good to the eye, crown isn't rough.

There is a "snug" spot in the bore near the rear sight, but far away from the muzzle.

Could this be a round bottom rifling issue? And we just need to play with different loads? Ive never had a gun with that rifling and it's a first for the owner too. Any thoughts or suggestions are welcome.

 

[Daveboone]

Have both the front and rear sights been adjusted? Have you shot it? There is only reference to the owner from the eighties having shot it and reporting it off.
I would get it to the range and shoot it to establish a baseline before worrying about anything else.

 

[EC121]

As Dave said shoot it first.
That rifling needs a thick patch to fill the grooves which then requires a smaller ball to prevent cutting the patch. I use a .526 with a canvas patch.
The snug spot in the bore could be from someone cutting the sight dovetail too deep or punching the dovetail to try to snug up the sight.. I would get a better measurement to the spot relative to the sight.

 

[excess650]

Colerain wasn't even a barrel company until 1990.

Is the muzzle and crown square?

Pull the breechplug and look down the bore to see if it appears concentric or if you see a shadow. Measure the muzzle and breech walls to see if the barrel was bored off center.

 

[Grenadier1758]

Colerain works the barrels to profile between centers. Still, the bore could be off center. Is the barrel identified by markings as to the manufacturer?

Do the measurements and observations as @excess650 instructs.

 

[rafterob]

12 inches off laterally at 50 yards makes me think an offset bore, which was not uncommon in some barrels. The simple fix if there was enough room was to offset the front and rear sights.. I have seen a couple rifles over the years with the sights set off of center at least 1/8" front and back. Looks kinda weird but the guns shot on target. Savvy builders that would recognize these barrels would assemble the rifles with the offset in the vertical plane so it could be corrected by front sight height only.

 

[Flintandsteel]

work up your best load, and bend the barrel.

 

[Notchy Bob]

My first thought was a non-concentric bore, positioned horizontally rather than vertically as is recommended. That’s been covered multiple times in posts above.

Another possibility might be that the barrel is bent.

Good luck!

Notchy Bob

 

[Rawhide67]

It's definitely a Colerain, I saw the name on the barrel. As for purchase date, I'm relying on my friends memory (he's pushing 80). I have not had a chance to shoot it, but when he bought it back a few weeks ago, the seller reported the same issue. And the sights were maxed out, rear all the way right and front all the way left. Even had glue on the rear sight to keep it in place.

May be able to do some shooting this weekend.

 

[Rawhide67]

Also, it's a swamped barrel but doesn't not appear to be bent to the naked eye. Although I have a lathe and thought about running it between centers, I'm not sure how helpful that would be on a swamped barrel. I have avoided the thought of pulling the breach plug, hoping for a simpler solution. Like round bottom rifling is very finicky etc...
Sounds like it could be if thin patches were being used.

 

[Wyogoat]

Forgive me if I missed it but is it shooting a decent group at 50? Even though it's off, if its grouping that says something about what may be the culprit.
I ask this mainly because my first longrifle was pieced together with what I could afford as a 13 yr old kid which included a straight Dixie barrel that was drilled way off center. The rifle shot great but the sights were as you describe.....although no glue to hold them at the extremes.

 

[Tasbay]

As above I noticed no mention of grouping. I have a Zoil Zauave that was about a foot high and a foot left but grouped well. Remedy was taller front sight , replace rear sight and drift both.

 

[bptactical]

Many will say a weapon “won’t shoot” and they need to understand 2 basic things:

Accuracy - is the projectile impacting the point of aim?
Consistency - are the projectiles in a group in a consistent group?

Accuracy issues are typically focused on things such as sights being misadjusted, bore runout etc.
Consistency issues are typically focused on things such as a barrel loose in a stock, sights loose, shooter error and the like.

Once you understand those nuances corrections are usually pretty simple.

 

[nchawkeye]

Won't shoot with a flintlock usually means it won't fire...Sounds like this one is just grouping off center, if groups are ok, bend the barrel just a touch...

 

[Grenadier1758]

This rifle may be a candidate for the barrel bending process.

Thin patches and deep radiused grooves would result in a spread out pattern not a group way off from point of aim.

 

[Rawhide67]

It does apparently group ok, just left of center. The bore isn't off center as far as I can tell, at least not enough to see it.

 

[duca]

Just bend the Barrel it’s not a big deal. You’ll never notice it

Anthony

 

[Tasbay]

Just out of interest can someone describe the barrel bending process. I know that's how the original ones were fine tuned by the Smith with eye looking down the tube.

 

[Semisane]

 

[smo]

I would center the sights on the top flat of the barrel and see where it shoots…
It sounds like the sights are positioned where you’re looking across the plane of the barrel…