I bought a used S&W 686-6 about a year ago. I notice that the firing pin bushing is slightly convex to the recoil shield and leaves a concave impression in softer primers when firing 357 rounds. If you place a straight edge across the firing pin bushing it is actually a slight bit above the surface of the recoil shield.
When I bought the revolver it had numerous problems so I returned it to S&W to correct the problem and give the gun a complete inspection.
The gun is very accurate and functions perfectly accept when cocking it slowly in single action sometimes I can detect a slight drag as the cartridge case heads go past the firing pin bushing.
I've got another 686-6 which I bought new and the firing pin bushing displays the same convex protrusion above the recoil shield. In that both guns have the same feature and Smith had the used one back for a check-up-- I guess this is normal.
I was wondering if it would be prudent to take a couple of swipes with an abrasive stone to remove some of the convex bump in the bushing (or is the hole that you see in the bushing perhaps cone shaped as it goes back to the firing pin and stoning would enlarge the front of the opening?)

As you can see in the photo, the 686 bushings do have a slightly angled "step" near the surface at the edge of the part. You are correct that the bushing should be flush with the recoil face or breechface. This protrusion would normally be filed down flush after the bushing was installed and staked into position.

(Alk8944 provided a correction with regard to the newer model revolvers, and some additional info....see post #5 below)

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Ret. LE, FA Instr, S&W Armorer

armorer951 thanks for the info.

Sir,

My dash 6 has the same 'feature' and it doesn't seem to hurt anything. I wouldn't try to stone it if it were mine, unless maybe it was affecting noticeably the smoothness of the DA pull.

Regards,
Andy

Contrary to what armorer951 stated the firing pin bushings in S&W revolvers have been domed for something like the past 30 years. As long as the gun functions correctly don't worry about it! It is simply a new design feature.

Yes, it looks odd! No, I have no idea why this change was done, just that it was quite a while ago! I would prefer to see them flat like the old guns too, but I wouldn't recommend filing it flat. I suspect they are harder than the older style that was dressed after installation. Shape could have been changed to make this step unnecessary since the bushing may be too hard to file! The dome would eliminate the sharp edge that would catch case heads while keeping the center high enough to properly support the primer.

This is one of those things that, just because they don't make sense to you, or aren't "The way I would have done it!", may still have a very good reason for their existence!

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Gunsmithing since 1961