Damaged crown on Mosin Nagant

[totallyunimodular]

I am a proud first-time gun owner with the recent purchase of a Mosin Nagant 91/59. The gun is in excellent condition and the seller was very helpful (GunBroker transaction; the guy who sold it me checked the headspace and firing pin protrusion and is machining me a no-go headspace gauge for free). But, the crown of the gun got damaged in shipping!

I have called around to local gunsmiths and most of them don't want to deal with it and the others want $70-$150. I have access to a good machine shop with lathes and so I was thinking of tackling this myself and am looking for advice.

With respect to the inside of the bore, I have seen videos like this one by Larry Potterfield on how to clean things up. What I am unsure about is how to deal with the gouge in the chamfer. Would I need something like this chamfer cutter on Brownells? I guess one option would be to simply cut the barrel back a bit and leave it with a flat crown, but I'd like to change the rifle's character as little as possible.

So, if any of you can recommend a good gunsmith in the Boulder area, please let me know! And, if you have some advice on how I can go about doing this myself, I'd love to hear that too. Thanks in advance

[blackford76]

Some of the re-arsenaled rifles were counter bored. That would be the best option for keeping it original.

[Circuits]

The chamfer cutter you referenced is for chamfering the forcing cone on a revolver, not repairing a damaged crown.

If you've got access to a lathe and are comfortable performing the work (and don't need to remove the barrel to get it chucked and concentric), then recutting the crown yourself is the quickest and surest way to get it fixed.

The reason you're getting high estimates is that most gunsmiths would insist on removing the barrel to do the job properly, and that (and reinstalling it after) is rather a big job in itself.

Brownells does have crown cutters for sale that will chuck into an electric drill, and you could use those without removing the barrel - but since that's a hand-steadied cutting job, it won't be as precise as a lathe job.

I've also heard of people recrowning with a marble and valve grinding compound - slather some grit onto a marble and work it for a few hours by hand while watching TV or something. It also won't be as precise as a lathe job, but is easier to center, and the resulting, curved crown would at least be better than the damaged crown you have now.

[Irving]

Excuse my stupid question, but it just looks like some scratches. Does this actually effect the rifle in any way?

[sniper7]

just shoot a few rounds through it and you will be fine

j/k don't really do that!

take it apart, put it in a lathe and do it yourself.

there are a few guys on here that are in gunsmith school. find out what they would charge.

[jackmode9316]

Excuse my stupid question, but it just looks like some scratches. Does this actually effect the rifle in any way?

A damaged crown will affect accuracy more than rust and pitting in a barrell.

[totallyunimodular]

Thanks to everyone for the responses. After weighing my options I have decided to tackle this myself. I am going to use a 6 fluted, 100 degree countersink to clean up the crown and muzzle. I'll follow this up with the brass bolt and lapping compound trick and then cold blue the area as needed. I'll post pics when I am done later in the week.

[CrufflerSteve]

Thanks to everyone for the responses. After weighing my options I have decided to tackle this myself. I am going to use a 6 fluted, 100 degree countersink to clean up the crown and muzzle. I'll follow this up with the brass bolt and lapping compound trick and then cold blue the area as needed. I'll post pics when I am done later in the week.

You might want to try some rounds from a rest at a short range, something like 50 yards or less. Then try after and see if there is a difference. Use the same ammo since milsurp 7.62x54R can vary wildly in quality.

Good luck. I've know people who've gotten good results with this method for milsurp - which used to be very cheap.

Steve

[totallyunimodular]

OK, I finally got to this this past weekend and I think the job came out nice. Here are some pcitures of the before and after (before pics are from June 9 and 10, after pics are from June 23): http://img30.imageshack.us/gal.php?g=p1000335p.jpg

I used a variable speed drill with a 1/2", 6 fluted, 100 degree countersink to iteratively work the crown until the gash was removed. I then used a series of very fine grinding stones (manually shaped on a grinding wheel to be conical in shape as opposed to a cylinder) to establish the crown and buff out the muzzle. Finally, multiple coats of cold blue and #0000 steel wool finished the job. Total cost: $0.00 I know that ideally I would have used a lathe (which actually sounds tough to do on a lot of lathes due to the big lug where the receiver and barrel join), a 90 degree countersink, etc, but it just felt insane to pay a gunsmith (those who weren't too busy to work on milsurp) $75 or more to repair a $135 gun. I think it came out reasonably well and I shot it on Father's day with good results. I won't bother getting into specifics here, since I had a new Mojo sight on it and was shooting some what I think was 147 grain FMJ rounds from who knows where. The next task is to buy a few boxes of Silver Bear, Brown Bear, Barnual and the like, and go out and shoot some more to figure out the gun and sights better. I am playing with keeping the Mojo front sight versus keeping the stock one on. I have to say though, after 25 rounds this past weekend, my shoulder was screaming and that was with a butt pad. I'll probably start a new thread on range results once I shoot some more and have some opinions. Thanks again to everyone for the advice and reading!