I thought I had the problem solved but it's still there.
My 38/44 HD will lock up (fail to rotate) the cylinder after the 1st or second shot. This shooting single action or double.
To date here is what I have done:
1. A complete cleaning, internals, cylinder, frame, throat.
2. Lubed all contact points inside the frame.
3. Cleaned under the extractor and verified the guide pins are
aligned, scrubbed the star and checked to see that it
not excessivly worn.
4. Checked each chamber with a dummy round and also
checked with six dummy round for correct rotation.
5. Smoothed out small burr around the locking point in
the shield using a hard stone.

After all of this I went shooting today and had some interesting results: using standard or +P loads the problem was still there: 2nd or 3rd shot would lock up the cylinder and in some cases I had to open the cylinder to get the gun to function. Fired cases showed NO swelling and there was NO primer cratering and NO drag marks on fired cases.
OK Here's the strange part: I shot some HD loads: 162 gr. hard cast SWC over 12.2 of 2400 and the gun worked flawlessly. Not a hiccup and accuracy was excellent.
So, for the HD Doctors out there what do I do next and PLEASE don't tell me to stay with the HD loads.
Any help greatly apprciated.
Thanks
Al.

If I didn't know better I would say your ejector rod is loose but it does not make sense.

__________________
Vaya con Dios

Check OAL on the rounds that were in the gun when it locked up and also see if the bullets were pushing out of their cases during firing of the guns prior rounds BEFORE it locked up!

G

David and Mosquito
Thanks for the comments. Ejector rod is tight and appears to seat properly.
I did check and the bullets are not walking.

Have you checked the ejector rod to be sure that it is perfectly true?

Possibly the heating up after some firing is enough to reveal a distortion that is binding the cylinder. Number the chambers with a magic marker to see if it occurs in the same position each time and look for any sign of a wear spot on the rod.

Bob

bettis1
I don't have a dail indicator setup but straight edge against the rod looks true. There is no one spot with noticable wear on the rod and I did do a round by round check on the cyl. after each hangup and it was random. I will try the magic marker at the next range trip: good point and thanks.

Did you examine the Hammer Nose Bushing? See Item No. 30 in this schematic... Numrich Gun Parts Corp. - The World's Largest Supplier of Firearms Parts and Accessories

Guns with a cracked Hammer Nose Bushing will often exhibit the same sorts of issues.

Drew

Sebago Son
You might have nailed it. There are two paralell marks on the face of the bushing (Facing the bushing the 9 o'clock position)Using a 10X glass they "could be" a crack. The bushing hole is rough (10X) but overall it is very hard to call a crack. How would asuch a crack cause the problem I've had?

If the bushing is cracked, the fragments will end up in different positions everytime you fire a cartridge.

Check your ejector rod again. I had a bent one that would lock up a chamber or two and make it hard to swing the cylinder out also as well as would not work the ejector star. I rolled it on a flat corian counter top and found the high spot and GENTLY tapped it down with a hammer. Now it works very smoothly working the ejector star, but it still binds a bid on two chambers of the cylinder. Same problem you are having. So it is still not perfectly straight even though by eye or even a straight edge it looks straight.

Try this, lay the revolver down and swing out the cylinder to where you can put something right at the very end edge of the knurled edge of the ejector rod. Now holding everything nice and still, turn the cylinder so it turns the ejector rod. Do you see ANY oscillation of any kind on the end of the ejector rod in relation to the stationary object you place right next to the ejector rod's edge? If you do, it is bent even though you can't tell by a straight edge. The reason you are experiencing it binding only on several chambers of the cylinder, instead on each chamber, is because the rod's high spot is hitting at that point when you are on those chambers. It may be possible to gently hammer tap out. But the best fix would be to just get a new ejector rod....if that ejector rod is bent and is causing the problem. Do you have another like revolver or a friend who could take their ejector rod out to test in your revolver?

If not, just take your ejector rod out and then close the cylinder with nothing holding the cylinder locked in the frame. Then holding the yoke tight to the frame with your hand, keeping the yoke to frame tight, either double action the trigger to turn the cylinder or pull the hammer back slightly and turn the cylinder by hand. If it does not bind on any chambers, that will tell you for sure that it was your ejector rod being bent causing the problem. That is something you can try right now. Just unscrew your ejector rod and check that. Then test it with fired cases next. It may have worked fine without cases in it but with cases in it if the ejector rod is bent even slightly it will force those case tight against the recoil shield. So try what I just said both with and without cases in it and see if your cylinder will turn freely in the frame with the ejector rod removed. If it binds either with or without the cases in the chambers, then the ejector rod is likely bent.


.

Shooter37,
same thing had my HD
Only a couple of things can cause the condition you described. One is dirt under the
extractor star. The other is excessive yoke end play, which is fixed by installing cylinder shims.

If it is "hanging up" because the front of the cylinder rubs on the back of the barrel
on some chambers, THEN it needs a shim. If it was hanging up because of **** under
the extractor rod, then it's already fixed.
You can tell by clicking through 6 empty shells (loaded into the cylinder) and watching
the gap between the front of the cylinder and the back of the barrel. If the cylinder isn't
RUBBING the barrel, you're fine.
If it is rubbing, you need to install a "shim" to take up the slack space.
Check it out. Use EMPTY brass.
Cheers!

__________________
Heavy Duty Enthusiast!!!!!

You may have addressed this, you mentioned primers not cratering, but how about backing out. Some lower pressure loads in rifles will result in primers proud of the case head, maybe different in rifles, I am not that experienced reloading for pistol, but I thought I would mention it.

Let me start with a BIG thank you to all who offered help. Now for some findings. I was able to do a dye check on the firing pin bushing face and found it was NOT cracked, at least there is no crack indication.
The point about primer backing out was also rechecked and even heavy and ver light loads show nothing abnormal.
This left the ejector rod and cylinder clearances. As best i can tell using the suggested checks, the cylinder rod is true. The cylinder clearence is now my suspect. With the hammer cocked and lowered down, trigger back there is less than .002" clearance between the cylinder and the face of the barrel. I think Lazcool is right: the firing hangs up the cylinder against the breech face. I'm going to try the end shake washers and try for a .005-007" gap.
Thanks Folks
Al

Oh, man. I am going to spend an entire weekend (THIS weekend) teaching an NRA Action/IPSC training clinic with Lazcool sitting right there, and every two minutes he's going to jump up and say "On the Smith and Wesson forum, this man said ´Lazcool is right...here's the link...´ and I'm going to have to send him off somewhere like the moving target just to get some piece and quiet.

I'll never hear the end of it. I had to put a .002 washer into his H.D. about three weeks ago.

cal,
Lazcool was on the mover but also was in the dishes (platos) with me!
that good that I didn´t say that I read this forum too.
jajjajjajajaj

Yes, Jose, he was very proud that he posted on the Forum, he was bragging to everybody.

I installed a .002 shim into my own Heavy Duty the other night. I was not really happy with my 25 yard groups. My cylinder face wasn't rubbing on the barrel and double and single-action pulls were fine, but the groups frankly weren't where I thought they should be. There was always one or two conspicous flyers that I was sure weren't my doing. We'd shimmed another N-frame a while back that WAS rubbing and upon shimming it found that the barrel rub went away and groups shrunk noticeably at the same time. Based on that one case, I thought it was at least worth a try.

So I shimmed it. Tests today showed nice 25 yard groups, so nice that we ran a target out to 50. I fired one 6 shot string at a B-27 from 50 and had 3 nicely in the 10 and 3 just outside the 10 ring in the 9. Total group size was about 5 inches at 50 and just slightly to the right -- which today might have been the wind or just the bright sun. Central Mexico, you know? Too much sun sometimes.

So that shim's staying in. A friend on the forum suggested I get an 11 degree cone cut, which I can do because our gunsmith has all the tools and I might still consider it -- but for right now, I'm happy with the Heavy Duty as it's shooting now.

by our government stupid ideas I have my finger asleep

I already feel the action of an N frame
good time to shoot is after 6 but it´s very fast night

From what I've read here, I'd suspect the ammo more than the revolver.
Since it works fine with some and not others, I'd segregate the 'bad' ammo and take a look at that.

Is it (the +P stuff) factory,,or reloads like your HD load using 2400 powder.

Different primers have different hardnesses. Brass cases can be a bit long O/A. I know you said there was no cratering/flattening, but that doesn't always tell the truth about pressures.

Does the firing pin itself retract fully within the frame bushing when the the trigger is released and the hammer retreats?
If it protrudes even a .000" or two,,it can hang up on a fired round that's set back.
A set back round (and they all set back or the primers wouldn't re-seat upon firing) can snag in the firing pin hole if the primer flows into it even the tinyist amount.
When the cylinder is locked up after firing a couple of the +P rounds are all the cartridges in the cylinder both fired and unfired are free to move back and forth?
Or is the one that just fired stuck solidly against the recoil seat in the frame.

More questions than answers I guess but just some thoughts that came to mind.
Truely hope you get her working again..

Calmex,
That's a really good Tip, many of us still learning about all this and I will write down this one. Since the cylinder face wasn't rubbing on the barrel and everything seems to work just fine, you would not think you needed a shim .
Nice tip to shimmed the cylinder to get a better group at 50 yards, thanks for sharing man.

Cheers!!!!!!!

__________________
Heavy Duty Enthusiast!!!!!

back in the 70s i had a model 27 do the exact same thing, i bought the gun used. after 3 or four shots it would lock up. i took it to smith and he never found the problem. i sold the gun and moved on. nowdays i would have to figure it out before i quit.

I had the same thig happen to my post war 38/44. It worked perfectly dry firing until you shot it with ammo and it would not work on two chambers. I finally sent it to David Chicoine, it had to have the barrel set back and an oversized cylinder stop installed. It shoots great now!

My MOD 10 1978 vintage developed a similar problem after a good bit of shooting and a lot of dry firing. The firing pin bushing in the recoil shield/standing breech had peened out a few thousands of an inch and would bind on the rear of the cylinder. I used a small fine file to level things out and no more problem 30+ years later. Apparently the fireing pin bushings may be a bit soft, but that makes some kind of sense, I guess, maybe. Ask for an ignition file at Autozone and see what they say.

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Fox Creek, Kentucky

Thanks again to all those who responded. It was a real education. 2152hq raised some good questions so let me respond. The ammo used that WORKED was an HD load of a 162 gr, SWC over 12.2 / 2400 using standard CCISPP.
This was sure fire, accurate, and reliable. Fired with any other load, including +P and even some old Fed 158 RN the gun would hang on the 3rd or 4th shot. My suspicion is that the ammo was OK it was just the heavy recoil of the HD loads that kept the cyclinder free.
Since my last post I have added 2 .002 bushings in the cyclinder just haven't been able to shoot yet. The bushings gave me a very uniform .005 B/C gap that was absent prior to bushing. I will post results after I fire the gun.