Colerain muzzle

[cjgregory]

Here’s my .50 caliber Colerain muzzle. I’m not sure how yours got that way. Home grown crowning attempt? Looking close at mine, it could use a little polishing.

 

[sportster73hp]

Looking at the picture up close it appears to show tool marks up /down on the flat face as though unfinished . In the hole, it is smooth at the break into the bore with an unsightly mark away from the important part. This mark may cause an issue maybe not.
Just shoot it some more and see how it shoots before doing anything drastic.

 

[longcruise]

Here’s my .50 caliber Colerain muzzle. I’m not sure how yours got that way. Home grown crowning attempt? Looking close at mine, it could use a little polishing.

Your's is round bottom rifling so it might be treated differently in production.

I have a fresh from the factory Coleraine in the "shop". I'll get some pics later.

 

[markdwhite15]

Thanks all, I knew it didn't look right for a factory crown . I can't do any accuracy shooting till I get my new mold, and laser surgery on my eyes. The VA keeps cancelling my appointment. Anyway, I'm gonna work on it this winter and if I don't like the way it comes out I'll cone it.

 

[longcruise]

Finally got around to taking a few pictures of the Coleraine barrel. This is a 40 caliber just as it came from Coleraine. It's much cleaner than the one above. Looks like a clean 45 or 60 degree bevel. A patch cutter for sure but easily remedied.

The breech end looks to have been done with the same tool but it's not squared up. Not a problem however.

 

[WonkyEye]

OP had me wondering about my .50 Colerain, I won't know how it shoots for a few months, but I will probably give it a quick pass with 800 grit just to knock off the sharp corners. I don't know why OP's has those gouges. If I had to bet, I would put my money on it having no effect on accuracy though

Edit: as a side note, I had a work trip that left the Colerain shop about 30 mins out of the way, so when I ordered my barrel I stopped and picked it up in person. I got a short tour of the shop, it was really interesting seeing the machines. I'm
such a nerd, because I get very excited about things like that. There were probably 20-25 different ones. I had seen rifling being cut before on a Williamsburg gunsmith documentary, the one I saw at Colerain use the same approach with a single cutter and paper shims, but not powered by hand. What was really fascinating, sorry I'm not a machinist so I will be using the wrong terminology, was the machine that scraped down the swamped profile. It had a cutter that moved on a linear bearing and above it a pressure plate that the operator would add shims to force the cutter deeper along the track. If I recall he said it was over a hundred years old, and modified to have an electric motor.