Got a new (to me) S&W revolver with a strange fouling pattern and acceptable but uninspiring accuracy. With a good cast bullet load, the forcing cone is clean, there's a little bit of leading at the ring (left over from bullet erosion?), then light streaks after. I slugged the bore and sure enough, it's even from the muzzle back to the loose spot then a very small bit tighter beyond the ring and before the forcing cone. There are enough threads on the S&W forum to leads me to believe that this is not uncommon, especially in the 696 model.

Does it make sense to try to fire lap that slight constriction before the loose spot?

A lot of posters with this condition are reporting good accuracy but I think it can do better than 4-5" at 50.

Have you slugged your barrel and your cylinders yet? If you are shooting cast bullets that are to small in diameter you will see leading. It is ideal to shoot a cast bullet at approx. .002" over what your barrel slugs at. So .429" should be approx. .431". .430" at the minimum.

How far in is the ring?
What about having a Taylor throat cut in the barrel? Would that clean it up?

It's hard to say exactly where the ring stops and starts but it's about centered at the front of the frame and ballpark 0.4" long. I'm afraid it would take quite a bit of Taylor Throating to get that far forward.

Bore and throat dimensions are good, throats are 0.0005-0.001" over bore and it doesn't lead that much, just a bit right at the jug and a little past. It just bothers me that the bullets have to bump up and then back down to get past the wide spot. Can't be helping accuracy any...

Is the barrel bulged sounds almost like some one had a bullet stuck at one time.

I would contact S&W and send it back.

If this is a non pinned barrel and the ring appears in the area of the threads then it is normal. What your seeing is deformation from the crush fit of the barrel threads in the frame.

Yes, it does look suspiciously like the result of a bore obstruction. It has done a round trip to S&W and they said it's fine and totally within factory specs.

young bill - this is interesting. It's a newer stainless gun. Perhaps S&W is trying to pre-empt a tight spot from thread crush and went a little too far?

I'm thinking the best course of action is to ignore it. Thanks for the suggestions.

Depending on how deep your rifling is I would make a hand lap with an old bore brush and lead alloy. When it cools either push it towards the breech to where it just sticks out a little and put some fine lapping compound on it. I say this so you don't remove it or you will have to orient it to the rifling. Just lap out that area to where your ring is.

There is a common bore restriction on most old pin style barrels on Smiths. I have a very fine shooting Model 19. My very good gunsmith friend said to check for that restriction. Sure enough it was there so I lapped it out. The revolver went from a fine shooting one to a superb shooting one.

I believe if Smith sent your revolver back and said it was within tolerances that what others said about normal for the crush fit barrels is correct and Smith was correct. Another very good friend of mine managed to put a ring bulge in the barrel of his 460 Smith. He sent it back to Smith and they charged him for a new barrel. His ring/bulge was further up the barrel though. They sent his old barrel back but cut it in pieces so it couldn't be used for anything.

Don't lap your whole bore.