627 Performance Center Question/Problem

[pwberndt]

Sorry, got into wrong Forum & not sure how. Thanks to whoever moved this.

My brother-in-law asked me to post this. He has a 627 PC that he purchased new about 3 months ago and it shoots fantastic. Since first fire, it has had flash marks on the cylinder and some lead build up at the top of the frame above the cone. We've looked at many of the Performance Center images in the group and have not seen the flash marks.

The last 150 rounds have been 158 grain Federal lead but the burn showed with 158 FMJs.

I'm afraid that if he keeps polishing the cylinder to remove the burn he will shine the finish. I can't figure out the lead buildup.

Is this normal and we are just not cleaning it, does he need to contact S&W or are we missing something?

Paul

 

[AzRedleg]

The lead build up seems a bit excessive after that few rounds.

The cylinder is going to get dirty but it is interesting the round burn marks on the cylinder seem to correspond to the indentation in the top strap.

Have you checked the cylinder/barrel gap and verified timing?

 

[KosherNRA]

The exact thing happened to my 627 pro that i loved. I even sent it to the factory (truly excellent customer service btw) and they sent it backssaying it was normal and measurements were fine.

 

[Porterb123]

As has been said, the circular mark is from the cylinder gap/ pressure being deflected from the top strap into the screw recess and back onto the exterior of the cylinder. Maybe a longer screw that would sit flush in that area and check the cylinder barrel gap.

 

[pwberndt]

The lead build up seems a bit excessive after that few rounds.

The cylinder is going to get dirty but it is interesting the round burn marks on the cylinder seem to correspond to the indentation in the top strap.

Have you checked the cylinder/barrel gap and verified timing?

The timing seems to be fine, the cylinder is locked before the hammer trips. The gap between the cylinder and cone is 6 thousands of an inch, but I don't know what the specs are. My Ruger LCR .38 is slightly tighter on the 6 but neither will take a 7.

The cylinder marks do align perfectly with the rear sight mounting screw. Obviously blow by being deflected. There are pieces of lead in the screw indentation.

I'm going to tell him to contact S&W because of the lead. I don't see how lead can be outside of the cone unless it is shaving the bullet.

Thanks to all for your comments.
Paul

 

[pwberndt]

Hi All,

Just a follow up. My brother-in-law called S&W this morning and explained what was happening and the service tech said that there should be no lead where it is building up nor should there be burn marks on the cylinder. They are sending a return order.

I'm thinking he will get a better revolver back than what he is sending in. Having said that, I can't imagine how it could get much better.

 

[BlueOvalBandit]

Hi All,

Just a follow up. My brother-in-law called S&W this morning and explained what was happening and the service tech said that there should be no lead where it is building up nor should there be burn marks on the cylinder. They are sending a return order.

The lead is one thing, the burn marks are another and is perfectly normal. It's leaving those shapes cause the gases are deflecting off the sight screw hole. Every S&W I have does that, shapes differ though.

 

[rbert0005]

The lead by the forcing cone is caused by the lead being vaporized when touched off.

You can fool with the powder charge and or hardness of the projectiles.
You may, or may not, be able to decrease the deposits.

In my experience, if you shoot lead you get leading.

The crud is going to happen as well. If you shoot the gun enough the cylinder will be pretty much all black.

Clean and repeat,
Bob

 

[BillyMagg]

As has been said, the circular mark is from the cylinder gap/ pressure being deflected from the top strap into the screw recess and back onto the exterior of the cylinder. Maybe a longer screw that would sit flush in that area and check the cylinder barrel gap.

That is exactly how Smith fixed my old 29 DX when my buddy bought and sent it in, they also reblued the cylinder. The longer screw was filed flush with the bottom of the top-strap, problem solved. Billy