What could be causing this?

[stevieboy]

Here's a head scratcher (for me, at least). Took my S & W Model 27 to the range this morning. Fired about 100 rounds of Speer .38 +P "leadless" ammo, a police training round that is supposed to emulate Gold Dots. After I had fired about 20 rounds the cylinder began hanging up one one chamber. When I pulled the trigger the cylinder would rotate about 1/2 way to lock up then would jam. I could free it by rotating it counterclockwise but even about 20 pounds of pressure on the trigger wouldn't make the gun cycle. On an empty cylinder the gun cycles just fine. I tried putting some empties into the gun and the gun seemed to cycle fine with them, too. Ditto for snap caps. But, with loaded rounds, it would jam up every 6th round (or 3rd, or 4th, etc., depending on the cylinder's position after I'd loaded it).

Ok, so I'm pretty sure one chamber's the culprit. Here's what I've ruled out:

1. The ejector rod is screwed in nice and tight so it's not a loose ejector rod that's causing the problem.

2. I've looked under the ejector star and that area is clean.

3. I've carefully checked my ammunition and, on every round, the primers are seated at about the same depth. In other words, it's not a high primer that's holding up the rotation.

4. I've checked for cylinder wobble when I rotate it and the cylinder rotates freely and without wobble.

5. There's no obstruction in the chamber that makes it difficult to seat a round.

6. There's no significant endshake.

So, what can it be?

 

[Microgunner]

I owned a S&W 617 8 3/8" that had very tight chambers. After firing a few rounds the empties would back out of the tight chamber slightly and drag on the recoil sheild, requiring a good chamber scrubbing about every 20-30 rounds to keep running. This did not happen with every chamber and a trip back to S&W cured the problem.

 

[hornetguy]

also, check for a granule of powder under the ejector. One little grain can cause a "high" spot that will hang up/lock a cylinder.

edit: sorry... didn't notice you'd already checked that...

I got nothin...

 

[Shadi Khalil]

Before you do anything, try some different ammo. I'd also try a different batch of the same ammo that caused the initial problem. If you still have the problem after that, I'd call S&W and take advantage of there great customer service.

 

[James K]

I also believe the ammo is the problem, but can't point to any specific reason. One possibility is that primers are backing out. Look for drag marks on the fired primers or on the heads of the cases.

Jim

 

[Michaelm45]

Is this a new problem?
Did you try other ammo?
It does sound like the ammo is at fault. It also sounds like you checked everything. Any more info?

 

[g.willikers]

I had something similar and it was the ammo.
Some of the cases were slightly fat at the back, just in front of the rim.
While they looked flush in the cylinders, they were sticking out just a little bit.

 

[Kreyzhorse]

Before you do anything, try some different ammo.

Very odd but I agree, try some different ammo.

 

[stevieboy]

I am going to try some different ammo. I've used this Speer ammo a lot in my .38s but this was the first time I fired it with the 27. I've never had a problem with it in my other handguns. The other possibility is that I noticed that the barrel-cylinder gap appeared to be very narrow to almost nonexistent on the one chamber that is tying up. But, I've had this gun for five years and never had a problem with it, so I cannot understand how the gap could have somehow narrowed on its own.

Here's another bit of weirdness, the gun dry fires without tying up. Doesn't matter whether I fire rapidly or slowly, the gun cycles perfectly when empty. That suggests an ammo issue, I suppose.

 

[a7mmnut]

My guess is one is backing out and jamming the hand and/or lock during rotation.

-7-

 

[bamaranger]

leadless, yuk

Loose that leadless stuff, unless you just have to shoot it at an indoor range and it is your ONLY option to shoot. And if you HAVE to shoot true leadless, I would not run it through a gem like a M27.

If it is really "lead free" as in green ammo, it may be operating at higher pressure than lead ammo, and may be more abrasive on your bore as well.

I'm not sure why this is, but much of our "green" ammo at work is marked +P.

Too, I have a theory, that "green" ammo, not intended for PD, LE, or combat, use, is not as closely watched for quality control as ammo that is leaded and will see such duty. This is my theory, not researched and based only on my experiece with green ammo as supplied by my agency. And a seemingly larger amount of said ammo has quality issues, like no primers, inverted primers, inverted slugs (no lie, a .223 round with the slug in the case UPSIDE DOWN, a .223 wadcutter maybe..........) and such when compared to conventional ammo orders that I have handled over the course of my career. But thats only MY observation on my limited window of things.

We shoot .223 green ammo and it gives our M4's fits. Yeah, I know, not a handgun round, but an example none the less.

Note, that some "leadless" ammo actually has lead core slugs, and simply use different primers and an enclosed base to make a "cleaner" round for indoor ranges.

Good luck with your problem.

 

[RamSlammer]

Most older Model 27's have recessed chambers. If that's the case with yours could be some debris or fouling in the recess causing the case to not seat fully. Toothbrush and bore cleaner usually will fix that issue (or a fine brass pick if its really fouled). Other than that, the case heads on that ammo could be out of spec . . . either too large in outside diameter or too thick. The over large outside diameter would potentially cause problems with recessed chambers. Too thick usually isn't an issue since most revolvers have a good deal of space between the rear of the cylinder and the frame.

 

[jinxer3006]

+1 for high primer

3. I've carefully checked my ammunition and, on every round, the primers are seated at about the same depth. In other words, it's not a high primer that's holding up the rotation.

Did you check before or after firing?

Primers initially back out on firing. As pressure builds, the case is pushed back which re-seats the primer.

Shooting light loads can cause the brass to not be pushed back far enough to re-seat the primer--I don't think this is your problem since you're using +P ammo. Maybe a bit of build-up in the cylinder(s) is causing the brass to "grip" the walls instead of moving back?

 

[stevieboy]

I'm beginning to be convinced it's the ammo. I've generally fired this gun only with 158gr. Magnums and never had a problem with it. Next trip to the range I'll try some of those. As for the Speer leadless, it's sold as police training ammo and it's always worked well for me in my .38s. But, one never knows.

 

[stevieboy]

Ok, NOW I know what's causing it and it ain't good. This evening I dry-fired the gun again. I noticed that the trigger felt heavier on one particular chamber and it was more apparent when I cycled the action very slowly in double action. After cycling the gun this way about a dozen times I swung the cylinder open and examined the cylinder face. Sure enough, there's a definite rub mark on the face of the cylinder corresponding with the "sticky" chamber. I then shone a flashlight between the cylinder face and forcing cone as I cycled the gun and noticed immediately that there was no visible cylinder-forcing cone gap at the point where the "sticky" chamber mated with the forcing cone.

So, obviously, the cylinder face is rubbing against the forcing cone at one spot. That's not enough to stop the gun from cycling when I dry fire it but it is when rounds are loaded into the gun (this is a non-recessed version of the 27). I'm guessing that the cause of this is a bent ejector rod although, I suppose, something else could be the culprit.

Dang it. This has been one of my favorite revolvers. The problem obviously is repairable but I just hate it that I have to deal with it. What I really can't figure out is how this could have happened. I treat all of my handguns with kid gloves. I don't slap the cylinder shut, I've never dropped the gun, I only use factory-spec ammo with it. Ah, well, I'll just chalk it off to experience and have the thing repaired.

 

[Rogervzv]

Send it to Ruger and it will be back before you know it. Don't blame you for being bummed. But it could be worse. Here in CA we have to wait 10 days to pick up a handgun, and we can only register a new one every 30 days. Talk about a lot of waiting.

 

[orsogato]

This is a no brainer. Call s&w send it in for repair and it will come back good as new in no time.

The customer service is the reason why I love s&w.

 

[Auto426]

Send it to Ruger and it will be back before you know it.

I lol'd at that one.

Has the gun been mishandled at anytime in the past? As in dropped on the cylinder, or had the cylinder flipped closed? This could possible cause the crane to bend, throwing the cylinder alignment off and causing the rubbing issue.

 

[Shadi Khalil]

Has the gun been mishandled at anytime in the past? As in dropped on the cylinder, or had the cylinder flipped closed? This could possible cause the crane to bend, throwing the cylinder alignment off and causing the rubbing issue.

Nope, OP's post #15

Dang it. This has been one of my favorite revolvers. The problem obviously is repairable but I just hate it that I have to deal with it. What I really can't figure out is how this could have happened. I treat all of my handguns with kid gloves. I don't slap the cylinder shut, I've never dropped the gun, I only use factory-spec ammo with it. Ah, well, I'll just chalk it off to experience and have the thing repaired.

 

[shortwave]

Since properly seated projectiles in the ammo shouldn't stick out passed the end of your cylinder, I don't see how the cylinder would not bind unloaded,not bind with snap caps but does bind loaded.:confused.:

I know you checked your primers for jumping seat but did you check the projectiles for jumping crimp also? Is it possible the projectiles in the unfired rounds are jumping crimp from the recoil of previous fired rounds?

Carefully measure lengths on 5 new rds. Load gun and fire till it hangs up. Unload and re-measure length on unfired rds.

You may have a slightly bent ejector rod but it seems to me the cylinder should bind with the snap caps also.

Is it possible you've got a combination of projectiles jumping crimp and a slightly bent ejector rod???

Since the pistol has never had an apparent problem, is it possible the projectile jumped crimp,jammed the cylinder and you exerted enough pressure on the trigger/cylinder to slightly bend the ejector rod???

Just a few thoughts!

But I'd surely check ammo overall length for crimp jumping.