19-4 cylinder binding, why?

[rc51kid]

I went to a pin match tonight using 158gr LSWC over 5.0gr Unique with Wolf primers in 38SPL brass. 3rd shot the cylinder bound up tight and I could hardly pull the DA trigger. I managed to get through the next few shots but it was tight. When I opened the cylinder and ejected the brass, I wiped down the front of the cylinder and it felt liked it spun fine. I have only shot the revolver one other time and it also happened. But I think it was after a bunch of rounds. So I figured it was lead/powder build up on the front of the cylinder. But this time I was surprised it happened on the 3rd shot. The cylinder/forcing cone gap is super tight. I almost can't see any light. If I am measuring right I can't even fit my .0015 feeler gauge. I thought for sure that it was binding on the forcing cone. But I am starting to think I might be getting tight from the rear of spent cases on the frame. Is that possible? There are some good sized rub marks on the frame in the 10/11 o'clock position from the firing pin hole. Why would the brass be sliding out and binding if that is what it is?
One other strange thing. When I was first starting to reload for this gun I loaded it up with primed brass to see if it ignite a prime, don't ask why. I aimed it in a safe direction and fired off a few pieces of primed brass. The fired primes looked like they backed out of the brass a little and it was difficult to open the cylinder. I figured this was somehow related to me being an idiot and firing primed brass. But what would cause the primes to slide out? I seat the Wolf primes very well and don't have problems in my Autos. Any ideas about any of this?
PS I am in the process of cleaning out the cylinder and barrel very well. It wasn't especially dirty but there was some buildup in them.

 

[Pisgah]

I'll let someone else guess at your binding problem. Could be any one of several issues.

But as for primers backing out, what you experienced was perfectly normal. When a loaded round is fired, the primer backs out -- but the recoil of the live round forces the case back against the recoil shield and forces the spent primer back in to the primer pocket. With no bullet, no powder, and no recoil, the primer backs out and stays out.

 

[murphydog]

The most common reason would be powder/fouling buildup under the extractor star; clean under there thoroughly and see if the problem is fixed.

 

[squidsix]

The second most common reason is the ejector rod backing out. Check that it's TIGHT and see what happens.

 

[rc51kid]

I'll let someone else guess at your binding problem. Could be any one of several issues.

But as for primers backing out, what you experienced was perfectly normal. When a loaded round is fired, the primer backs out -- but the recoil of the live round forces the case back against the recoil shield and forces the spent primer back in to the primer pocket. With no bullet, no powder, and no recoil, the primer backs out and stays out.

This is exactly what i figured at the time. That is why i didnt think much of it then. But i figured it might be worth mentioning now.

 

[rc51kid]

The second most common reason is the ejector rod backing out. Check that it's TIGHT and see what happens.

Sorry but i am a little slow right now. What do i need to check tightness on? Isnt the ejector rod spring loaded? Or do you mean where it screws in?

 

[squidsix]

Yes, the ejector rod is threaded, and they often back out on these, especially before they were changed to left-hand thread.

 

[stantheman86]

Yup, had my old K-22 unscrew the rod on me, and lock the gun up solid until I could work the rod tight and open the cylinder. Put a nice wear mark on the blue on the ejector rod lug too

 

[rc51kid]

Yes, the ejector rod is threaded, and they often back out on these, especially before they were changed to left-hand thread.

i took the ejector apart and cleaned and lubed it. It didnt look that dirty, but it does feel a little smoother now. I am not really sure that was causing the problem or not.

 

[H Richard]

If you have a distinct "rub mark" on the recoil shield at a particular location, you could have a bent crane (yoke). Other than that, I agree with murphydog on the cleaning under the extractor star, especially with Unique powder which is coarse and doesn't burn the greatest unless a heavy crimp is used. It can leave lots of unburned granules and when you eject then be sure the revolver is pointed barrel straight up so any unburned granules fall straight out.

 

[rc51kid]

If you have a distinct "rub mark" on the recoil shield at a particular location, you could have a bent crane (yoke). Other than that, I agree with murphydog on the cleaning under the extractor star, especially with Unique powder which is coarse and doesn't burn the greatest unless a heavy crimp is used. It can leave lots of unburned granules and when you eject then be sure the revolver is pointed barrel straight up so any unburned granules fall straight out.

Yes i have a rub mark on the recoil shield. I will try it out since i cleaned under the extracer and see if it is fixed. But how can i check to see if the crain is bent or straight?

 

[GUNFUNCO]

There can also be other reasons for what you are experiencing.

If the loads are too light, the primers don't re-seat the primer even when you have a bullet and a load of powder in it.

if the loads are too hot and/or the primers too soft, you may get cratering around the firing pin hole.

The little lip of metal that craters up around the firing pin when the round is fired will bind up the revolver.

Sometimes the little ring of metal will be shaved off when you open the cylinder.

That's why after you force the cylinder out, if you re-close the revolver, with the same empty brass still in it, it will not bind-because you tore off that little ring when you forced the cylinder open.

 

[Alk8944]

I almost can't see any light. If I am measuring right I can't even fit my .0015 feeler guage.

Funny, no one seems to have even noticed this comment! This is not a normal condition and usually points to another condition which needs to be addressed, end-shake. Have you checked for this?

Check in this order:

End-shake. Is there noticeable end (axial) play in the cylinder when closed? If there is the cylinder needs to be shimmed to reduce it to barely perceptible (.001-.002"). Make sure the area under the extractor is clean, brush it thoroughly with a toothbrush.

Once you know end-shake is correct check headspace. This is the distance between the back of the cylinder to the breech. With cases in the cylinder there should be from .005-.010 clearance. Another place for your feeler guages.

Extractor rod. Open the cylinder, and while holding the cylinder try to turn the extractor rod. Direction doesn't matter, if it turns it is loose and needs to be tightened.

Extractor rod 2. Runout. Once the rod is verified to be tight, while the cylinder is swung out, try spinning the cylinder and watch the end of the extractor rod. If it runs true is is straight, if it wobbles it is bent. If bent it needs to be straightened or replaced.

Finally, once everything above is OK, check the cylinder again. While it is swung out does it rotate freely on the yoke? Now close the cylinder, pull the hammer back just enough to unlock the cylinder and see if it rotates freely all the way around. Watch the B-C gap as you turn the cylinder and be sure it isn't dragging on the barrel breech (It isn't the "forcing cone", that is the tapered internal surface inside the barrel breech, it has no dimension, and no surface that can contact the cylinder). If it does, then the B-C gap must be adjusted to between .004-.010.

Now, with everything else eliminated and it still drags, it is likely the cylinder has been shimmed for end-shake and whoever did it over-did it, and the cylinder is binding between the end of the yoke arbor (inside the cylinder) and the standing breech where it is contacted by the extractor center bearing. The yoke arbor could have been stretched too. Either the yoke needs to be cut .001-.002, or a shim removed, depending on what was done.

Finally, if I understand what you said, the gun starts out OK and starts to bind up after 1-3 cylinder loads are fired? If this is correct I will bet it is how you are handling the revolver. What I mean is you are extracting fired cases with the muzzle of the gun pointed downward, am I right? What happens when you do this, is un-burned powder grains fall from the cases and under the extractor. These act as spacers and hold the extractor up making the assembly too long and causing binding. Perfectly normal! If, instead, you hold the gun muzzle up and let the empty cases fall from the cylinder, then the un-burned powder stays in the cases and doesn't fall under the extractor. The vast majority of times the revolver begins to bind after 1-3 cylinders the problem can be solved by how the gun is handled for extraction of fired cases. Carry a toothbrush when shooting anything. It's amazing how often it will be used.

Cases sliding out of the charge holes. This is normal and will not cause binding. Rub marks on breech? Of course there are. When the cylinder rotates with the muzzle up the case heads drag lightly and eventually cause wear. As long as headspace if adequate these do not relate to your problem. GUNFUNCO mentions several items, none of these would be related to number of rounds fired. No load that will dependably get the bullet out of the barrel is too light to re-seat primers in a revolver!

 

[stevieboy]

I'm surprised that no one so far has identified an obvious cause for your binding: your gun's cylinder face may be rubbing against the forcing cone. You say that the barrel-cylinder gap is "super tight" and that with at least some chambers you cannot visualize daylight between the cylinder face and the forcing cone. Lack of a barrel-cylinder gap is an obvious reason for binding.

I own a 625JM (.45 ACP) revolver that I picked up used about a year ago. A nice gun except that, after just a few rounds down range, it would start to bind. I thought of every possible cause -- dirt under the ejector star; high primers on some rounds; possibly a bent ejector rod; carbon buildup on the cylinder face. None seemed to be causing the problem. I cleaned carefully under the ejector, I closely examined the primer on every round that I fired, I checked the ejector rod for wobble; I removed every bit of grime that I could from the cylinder face. The gun still bound up after it had gotten warmed up just a little.

Finally, I took the gun to a local smith. After listening to my tale of woe he took the gun and attempted to shine a flashlight through the barrel-cylinder gap while he cycled the gun. It took him only a couple of seconds for him to say that the problem was caused by an unduly tight barrel-cylinder gap. He had the gun ready for me on the afternoon of the same day that I'd brought it in. The gap was widened to .06 inches and the gun cycled flawlessly.

 

[rc51kid]

Extractor rod 2. Runout. Once the rod is verified to be tight, while the cylinder is swung out, try spinning the cylinder and watch the end of the extractor rod. If it runs true is is straight, if it wobbles it is bent. If bent it needs to be straightened or replaced.


I can see a slight wobble in the ejector rod. But i dont really see what it would bind on. WWHat about the ejector rod being bent would couse binding? The cylinder still looks like it spins true. So would a bent ejector simply bind in the under lug area? Because if that is the case i would think it would bind as the guns sits now (clean). But right now with snapcaps or fired brass in it it funtions great and runs smoothly.

I have not had it to the rang yet since i cleaned the ejector/extractor parts. So i dont know if that might have been causing the binding.

 

[Alk8944]

The front end of the extractor is locked in by the locking bolt in the barrel lug. As the cylinder turns on this and the rear pivot point it can cause the yoke to move in and out. If the bend is great enough, when the yoke is pushed into the frame, the binding occurs on the side of the extractor rod where it passes through the yoke. How much it binds, or if at all, depends on how tight the locking bolt is fit and how much runout there is in the extractor rod.

If the cylinder turns freely now, it will when it is loaded, and your question has been answered, the binding is caused by un-burned powder grains under the extractor! Take your toothbrush along. When it starts to bind or get difficult to close brush the back (toward the cylinder) of the extractor and it's recess.

 

[hsmith9491]

barrel-cylinder gap

Stevieboy don't you mean .006 gap not .06 (.06 is about 1/16 of an inch)

 

[XR750]

Binding cylinder

I had trouble with binding cylinder on a mod 28 with a 4" barrel.
I was reloading with DuPont IMR 4227 and it wouldn't burn all the powder and unburned powder bond the cylinder crane and under ejection star.
I switched to Unique and no more problem.
XR750

 

[H Richard]

Since it appears now it is unburnt powder under the extractor star, one "trick" shown my by a S&W trained armorer was to (with cylinder open) push the extractor rod all the way, then let snap shut just a couple times. In most cases this will dislodge the tiny particle that is hiding from you. I prefer to use canned air after a brushing with solvent.

 

[stevieboy]

Yup, meant to say .006.