Tight cylinder gap in S&W 625

[Boats]

Just got my re-barreled 625 back from the gunsmith. He said the cylinder barrel gap was tight. Minimum factory spec and I may feel some drag when the gun gets dirty. Fairly common IDPA load. 3.9 Hodgen Clays 230 gr LRN bullets.

Match last night he was right, about round 60 or so could feel it dragging, Couple of targets it was real hard to pull then broke free and shot went off. With predictable poor results on target.

As a practical matter since we run a cold range I can't take the gun out of the holster and brush or lube the cylinder face. So matches with long courses of fire are going to be a problem. Unless it works itself out or I should lube it somehow. Run the front of my cylinder dry now

Any advice ?

Boats

[Rolex]

PLEASE- for your own good- send it to:

Mike Carmoney- he is in the dlr. section

of this forum! He is the best!

[Pezco]

+1 on Mike's work! I had my 625 tweaked by S&W Performance Center, and will be sending it to Mike for additional work.

Edited August 20, 2009 by Pezco

[Toolguy]

First check and make sure there is no endshake. You can get a tool from Brownell's to cut back the barrel while it's on the gun. You need five to six thousandths cylinder gap for lead, 3 to 4 if you only shoot jacketed. You can also try spraying some Dillon case lube on your cylinder face and

back of the barrel between runs. The auto guys put it in the comp to keep junk from building up in there. They should have a safe area someplace where you can do that.

[Carmoney]

Frames and cylinders don't change dimensionally on their own, so if this is a new problem, it almost assuredly means that the yoke barrel has been slightly shortened, allowing the cylinder to shift forward and rub the back of the barrel. This can occur as a result of intentional alteration, or through wear over a long period of time. If this problem was not occurring before it went to your gunsmith, it almost assuredly means he shortened the yoke barrel too much in an attempt to solve some other binding problem, then didn't know how to fix it.

If the gun has always exhibited this tendency, then it probably always has had insufficient cylinder/barrel clearance.

Forget lubing the cylinder face. That won't do you any good.

Before cutting back the rear of the barrel to create additional clearance, I would recommend installing one or two .002" endshake bearings, if they will in fact fit in there, to set the cylinder back where it belongs. The extractor assembly has to be disassembled from the cylinder (despite what Jerry M. indicates on his DVD!) to do this.

If the gun has no perceptible endshake--if the cylinder won't move at all when you grab it and try to force it to move backwards and forwards with the cylinder closed--then increasing the cylinder/barrel gap by a couple thousandths should solve the problem.

The only other thing to check would be carry-up and chamber alignment--if it's spitting lead, you may be getting a gradual build-up of lead spray welded onto the cylinder face until it binds. I have this issue with my old Baumannize custom 7-shot Model 27 I used for pin shooting all those years--I did everything I could to fix the problem only to discover that one of the chambers (or perhaps one of the cylinder stop notches) was bored slightly off-kilter, causing one (but only one) of the chambers to not line up quite right with the forcing cone.

PM or call me if you need further help.

Later,

Mike

[Boats]

Mike It's a brand new barrel, Switched it from 5 inches to 4 for IDPA shooting. It has the slighest bit of end shake. Hold it up to the light you can see a bit of difference pulling the cylinder back and forth as well as just a bit of feel. I may stick a feeler guage in there see if I can measure it.

I did not think it was going to get any better shooting. Not enough to make a difference anyway. It messed up one or two of my shots in the match. Inconstent pull. I am going to get it back to my local "Smith" and see if he can set the cylinder back just a bit. Tight is no doubt good but too tight is a PITA, looks like what I have here.

Boats

[wide45]

Make sure that it is the cylinder face that is dragging.

If you get powder flakes or ash between the extractor and cylinder, you will get a horrific trigger pull the first round or two after a reload.

[Boats]

Wide I never thought about that, This pull got better after I pulled through a couple of rough ones. Am shooting it again this Sunday. Will watch close.

Boats

[Carmoney]

Mike It's a brand new barrel, Switched it from 5 inches to 4 for IDPA shooting.

Aha......the rest of the story!

Who installed the barrel? Smith? Or smith?

[Boats]

Mike,

Gunsmith. I am going to shoot it some more and see if it repeats. I need it to be right end of October, He will stand behind his work, just like to know what's going on myself.

Boats

[Carmoney]

Mike,

Gunsmith. I am going to shoot it some more and see if it repeats. I need it to be right end of October, He will stand behind his work, just like to know what's going on myself.

Boats

Gotcha. It's probably still just a little too close on the clearance, then. Sounds like it's only a couple thousandths off. If there's not a lot of endshake, a couple judicious file strokes is probably all it needs. You'll get it figured out.

[Boats]

It's not the gun, I shot it couple of matches since. First one had the same problem. Back home looked at everything carefully including my Ammo. I had taken my seating die out of the press, so it could be used in a Lee Nutcracker tool at the range while cronoing loads.

Did not put it back in all the way down. My cartridges were just a bit too long and not crimped quite enough. Suspected this when the moon clips were not dropping in easy. Barrel switch never touchingh the cylinder gave me the clue. This gun had always dropped moons in easy. Ran that lot of ammo back through the seating die and match last night no problems at all.

Boats