Binding Cylinder?

[tpaw]

Yesterday I was shooting my S&W 340PD .357 Mag. using .38 154 grain +P ammo. After firing about 30 consecutive rounds, I found that I had to push the cylinder shut with more pressure. Do you think the metal was expanding causing it to bind? I could not see anything wrong with the gun. I put it down for a while and it worked fine. I've never had this problem with any of my other revolvers.

 

[jfh]

See the M&P340 thread. Somel of us have had trouble with cylinder binding with reloads--the yoke can bind up, apparently due to lead / powder residue. Remove the yoke and cylinder, and remove the cylinder, then clean the rod, cylinder rod bore, etc., etc. I'll bet it goes away.

FWIW, it appears to be tighter tolerances in the 340 assembly--such binding doesn't occur on my 640 until perhaps 250 rounds.

Jim H.

 

[jad0110]

Start simple:

1. Make sure the ejector rod hasn't loosened.

2. Do you eject your empties straight down (or nearly so)? Supposedly, ejecting empties while the gun is horizontal, or with the muzzle pointing towards the ground can increase the risk of unburned powder/other crud getting under the ejector star, which can cause it to not sit flush against the back of the cylinder, making the cylinder to bind against the breech. I may not have said that exactly right (forgive me Fuff!), but that's the gist of it.

 

[Old Fuff]

While I can't speak to the S&W, I am aware of problems with a competitor's titanium cylindered revolver caused by a tight cylinder gap combined with the cylinder expanding following protracted firing. I suggest you shoot 30 or more rounds in 5-shot strings while giving the revolver time to cool between strings. If it doesn't bind up after 30 rounds you may have identified the cause of your problem. Then I'd take it up with S&W's customer service department.

 

[tpaw]

Thanks for all of your help. I'll give it a try.

 

[Mr.Revolverguy]

I just experienced this on the range this weekend. Make sure to clean under the ejection star. I got it home and pushed the ejector rod up low and behold there it was unburned powder. Took a nylon brush and a little kroil to it and good as new.

 

[Old Fuff]

I put it down for a while and it worked fine.

Given this, I don't think the problem is being caused by unburnt powder under the extractor star, or an unscrewed ejector rod. It would seem that the revolver was O.K. after it cooled off.

 

[Rexster]

If setting the gun down to cool solved the problem, then expansion due to heat is likely at work here. Powder fouling could be contributing, also; it could be a bit of both. Tight tolerances make both issues happen more readily.

 

[tpaw]

I was thinking that the metal was expanding due to heat, but can that really happen after 30 consecutive rounds being fired? Are the tolerances really that close?

 

[Old Fuff]

It can because of the nature of Titanium which is elastic, especially if the barrel/cylinder gap is close (.003" or less).

The clue I see here is that if you let the gun sit a bit, it works. That wouldn't be the case with powder fouling under the extractor star, or an unscrewed extractor rod.

This is one reason I stick with steel cylinders, in either steel or aluminum frames.

 

[tpaw]

It's a concern, but for a pocket revolver, I doubt I'll ever need to fire 30 consecutive rounds. If I can't do it in 5, the battle is lost.

 

[Old Fuff]

If I can't do it in 5, the battle is lost.

I think that's Smith & Wesson's perspective to.

I pocket carry various revolvers, both all steel and steel/aluminum, chambered for cartridges up to .44 Special. With a good pocket holster I don't find this to be difficult, and if I have to shoot in defense of my neck the extra weight and recoil control would be welcome. While it probably wouldn't happen, I have some concerns that a Titanium cylinder could bind before 5 shots had gone downrange, but in my circumstances I don't have to worry about it...

 

[tpaw]

I have some concerns that a Titanium cylinder could bind before 5 shots had gone downrange

That I can assure you has never happened to me. It took 30 plus consecutive rounds and I'm still not convinced it was an expansion problem. I'll give it a good cleaning and shoot the 357 the same way and see what happens. I'll keep you posted after this weekend.

 

[Old Fuff]

That I can assure you has never happened to me.

I suspect your right, but in my case there is no possibility...