I have a M10-7 that has a burr on the hammer nose bushing that protrudes outoutwards. It's pretty small but it causes a problem by binding up the last round or two in the cylinder making the trigger (in D/A ) hard to pull or hammer hard to cock (S/A). I was thinking of touching it with a stone but wanted to see what you all thought first?

I have a M10-7 that has a burr on the hammer nose bushing that protrudes outoutwards. It's pretty small but it causes a problem by binding up the last round or two in the cylinder making the trigger (in D/A ) hard to pull or hammer hard to cock (S/A). I was thinking of touching it with a stone but wanted to see what you all thought first?

I would stone it. I replaced the firing pin in my 610 with c&s long firing pin. The gun started to lock up. It got so bad that the last time I had to put a pin down the barrel and bump it with a small hammer. I knew the firing pin was doing it, but didn't know why. When I tried to remove the firing pin, it was stuck. Either it was over size, or the hole had closed up some. I finaly got it out. I had to open the hole some with a very small file. Then I used some 1000 sandpaper to remove any burs. Its hard to work in a hole that small. I fixed the problem. These guns come from the factory in a semi rough state. I don't hesitate to smooth thing out some when its needed.
Phil

Before you take a stone to that FP bushing burr, consider this: stoning will remove metal, and possibly enlarge the FP hole, creating additional problems.

I would use a small hammer, a bore diameter metal rod through the barrel, and a medium-sized 3/8-1/2" ball bearing to tap the burr back down. Then, stone it lightly finishing with abrasive cloth wrapped around a flat bar. Remove minimum metal this way, and prevent enlarging the FP hole.

JT,

The firing pin hole is already enlarged, that is where the metal came from. Peening will just result in the burr being pushed back and not where it came from.

dmbrewer,

Just stone it off as pberry said. I have done literally hundreds of these over the past 50 years with no negative effects. If you start getting cratering where the primer flows back into the enlarged hole then the bushing needs to be replaced.

The cause? Contrary to advice often seen it seems to be from dry-firing! Every one of my guns which have been dry fired develop that same burr. The ones I have bought new or in un-fired condition, and I have scrupulously avoided dry-firing have never developed this type of burring.

While you are at it, look closely at the breech face. There are ratchet burrs on the face and the centerpin hole is rounded off on the sideplate side. This revolver has been abused at some time by slamming the cylinder closed or closing it by the movie wrist-flip. I have seen much worse, but this one shows the damage.

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Gunsmithing since 1961

Yeah, I think it was played with more than it was ever shot before I got it.