Bad crowning job

[daniel craig]

So I took my mosin to get cut and crowned but I think the crown looks....not well done...admittedly I don't know what it's supposed to look like so I'm posting pictures that I'd like you all to look at. It seems rather rough around the inside edge, is it supposed to be?

 

[solvability]

No that is not smooth and it should be crisp and clean.

Shoot it and see how it groups - likely some of that will blow off in a few rounds but it should not have been delivered in that condition.

 

[WelshShooter]

Yowza, that doesn't look too pretty I'm afraid! I would take it back to the gunsmith (assuming it was a gunsmith you took it too) and get them to do a proper job. Here's an example of a counter-sunk crowning (I think that's what it's called?) along with an 11 degree match crown. The crown is the most important part of the barrel, it doesn't matter if everything else is good, if the crown is botched then accuracy will suffer.

 

[RainDodger]

Just for grins, here's another. They should be nice and clean.

(.17HMR)

 

[Snowdog]

Maybe the goal was to keep it ugly, keeping tradition with the Mosin?

Seriously though, it looks like a step was skipped there. Have you had a chance to shoot it yet?

 

[briansmithwins]

That's nasty.

I'd inquire about a refund and take it to a competent smith.

Letting a butcher take another cut rarely works out.

BSW

 

[Gtscotty]

I've cleaned up a bad crown job with a round head brass screw. You apply some valve grinding compound to the screw, chock it in a drill and slowly hone the crown. It sounds janky but works well, I think there was a how to on Midway's website at one point. If it was my mosin that's what I'd do, the Cz I tried it on is a shooter.

 

[Snyper]

I've cleaned up a bad crown job with a round head brass screw. You apply some valve grinding compound to the screw, chock it in a drill and slowly hone the crown. It sounds janky but works well, I think there was a how to on Midway's website at one point. If it was my mosin that's what I'd do, the Cz I tried it on is a shooter.

That's a simple easy way do do a crown.
You can also use a bullet instead of a screw

 

[mf-dif]

Thats the way ive done it as wellwith my mosin. Brass screw in a drill works great.

 

[splattergun]

yes, it looks like the smith forgot to chamfer that burr. Have him finish it.
Or use the screw trick.

 

[ColtPythonElite]

I've cleaned up a bad crown job with a round head brass screw. You apply some valve grinding compound to the screw, chock it in a drill and slowly hone the crown. It sounds janky but works well, I think there was a how to on Midway's website at one point. If it was my mosin that's what I'd do, the Cz I tried it on is a shooter.

Yep, I have done several that way with good results.

 

[bikemutt]

I'm just wondering here if bad crown jobs are expected, or just expected on Mosins?

Guess I'm just trying to understand why I should cleanup after my gunsmith, whom I've paid to do a job.

 

[rcmodel]

It looks like the remenents of cutting a chrome lined bore.

Chrome is too hard to cut cleanly with HS steel lathe bits.

But, Mosins were not chrome lined as far as I know?


I'd take it back to the guy that cut it and have him lap it with a brass lap and valve grinding compound.

rc

 

[Gtscotty]

I'm just wondering here if bad crown jobs are expected, or just expected on Mosins?

Guess I'm just trying to understand why I should cleanup after my gunsmith, whom I've paid to do a job.

Well with mine, I was not happy with the quality of the cut/thread/crown job that was done on my CZ 455 barrel. I didn't want the guy to touch it again, and I didn't want to pay someone else to clean up his work. My crown looked like the OP's and the barrel couldn't hold a group in a bucket. $5 in materials and 5 minutes in work later and it shoots great again. When the fix is so easy why wouldn't you try it? I guess the OP can go back and get his "gunsmith" to fix his crown, but after mine proved to me that he couldn't run a lathe, I wasn't too inclined to give him another whack at my barrel.

 

[bikemutt]

Well with mine, I was not happy with the quality of the cut/thread/crown job that was done on my CZ 455 barrel. I didn't want the guy to touch it again, and I didn't want to pay someone else to clean up his work. My crown looked like the OP's and the barrel couldn't hold a group in a bucket. $5 in materials and 5 minutes in work later and it shoots great again. When the fix is so easy why wouldn't you try it? I guess the OP can go back and get his "gunsmith" to fix his crown, but after mine proved to me that he couldn't run a lathe, I wasn't too inclined to give him another whack at my barrel.

That makes sense, thanks.

 

[joem1945]

Boy, that is nasty. I've recrowned several of mine and it's not hard at all. check Midway or Brownells for barrel laping tools and compound. The only other thing you need is a electric drill.

 

[rbernie]

I have on several occasions used a 1" fine grinding ball spun by hand to take the sharp ridges off of a crown before lapping. I first chose a round ball because it seemed to inherently self-center, and it seems to have worked just fine.

 

[daniel craig]

Thanks everyone! I ended up taking it to another gunsmith, I'll be picking it up on Tuesday!

 

[Wreck-n-Crew]

I have used a 1/4"20 brass screw head chucked in a drill with some glitz green on a crown with great results but i have never used it on a flat recessed crown. Seems like a bad idea...but I'm no expert.

Maybe post the pics over to the gunsmith section and have someone with a little more knowledge than me give some feedback?

Edit: sorry posted this a little late...



Sent from my LGLS991 using Tapatalk

 

[Carl N. Brown]

gtscotty: "I've cleaned up a bad crown job with a round head brass screw. You apply some valve grinding compound to the screw, chock it in a drill and slowly hone the crown."

I have been told the geometric principle is that a sphere (round screw head) finds the center of a cylinder (the barrel). The round brass screw head also seems to work better than a bullet; round brass screw head and metal polishing compound improved my rifle; the key is to work slowly and carefully. There are videos available if one searches. The formal gunsmithing tool for such crowning is a ball.

 

[Taurus 617 CCW]

Yeah that is a bad crown job. That would be a D+ job in a gunsmith school. It looks like he didn't finish up the job with sandpaper like he was supposed to. Here is an 11 degree crown I did on my 22/45 just before I sent it off for plating. Sorry for the slightly blurry photo. I was using a 3mp phone camera. Glad to hear you took it to another guy. I am interested to see what it looks like when it gets back.

 

[witchhunter]

Barrel crowns are seriously bad ju-ju. I have heard of the DIY with a screw, but I have always taken mine to my smith to get it done right.

 

[Liberty1776]

Please let us know how it turns out after you pick it up on Tuesday...