629 locking up with mag loads

[drumsetdrummer]

Hi all,

This is my first post, so forgive me if this is the wrong forum. I have also searched and not found anyone reporting this specific issue yet.

I have a 629 Classic 6 & 1/2" I purchased last year. When running hotter (at or just below max loads), the revolver will sometimes completely lock up. The hammer won't move, the trigger won't move and the cylinder release won't push forward. It just locks up hard.

I have so far been able to get it to eventually unlock by continually attempting to lower the hammer, move the trigger, push the cylinder release over and over and eventually it gives and I can use the gun again.

Any ideas on what is going on? Anything I should look for? Should I just send it back to S&W?

 

[AudieMurphy]

I'd say send it back and let them have the frustation of figuring it out..Because if you or someone else atempted to repair that may void the warranty

 

[WR Moore]

While I tend to agree with sending it back, I have to ask: Does it do this with factory loads? S&W is going to test it with factory loads and if it doesn't do it with them, they're gonna send it right back.

This could also be a clue that there's something about your loads. Just because it's below max in your load manual, that was the max for that particular example or test barrel.

 

[ken158]

Pretty hard to to figure out but I would check for high primers, ejector rod loose, strain screw tight? Report back and you will get more ideas to check for a problem.

 

[drumsetdrummer]

While I tend to agree with sending it back, I have to ask: Does it do this with factory loads? S&W is going to test it with factory loads and if it doesn't do it with them, they're gonna send it right back.

This could also be a clue that there's something about your loads. Just because it's below max in your load manual, that was the max for that particular example or test barrel.

Good question, but yes it does it with some cheap but hot factory PPU loads. I have been working up a load starting from minimum and it locked up as I got near max. So that is why I'm thinking it only does this with hot loads.

 

[murphydog]

It would be interesting to know what powder, charge and bullet you’re using for “at or max loads” and the source of this data. If they are within factory recommended specs it may be a gun issue, but if they are overpressure that is a different issue.

 

[stansdds]

PPU is Prvi Partizan, that is factory ammo unless you are just using their brass or buying from a commercial reloader. Since it happens only with Prvi Partizan ammo, I'd say that it has something to do with that ammo. My guess is that you are getting primer cup flow into the firing pin hole, but that's just a guess.

 

[WR Moore]

I'll second stansdds. Break down and buy a 20/50 pack of Federal/Remington/Winchester and see what happens. I had cylinder lockup a couple of times with some PPU .38 Spl LRN. Not as severe as yours, a hearty yank on the hammer spur generally took care of the issue.

I had extraction issues too. I think the thicker cases were sticking to the chamber walls and not springing back like other brass.

 

[chief38]

My first guess would be that the stiff loads are causing the bullet to creep out of the case and jam things up against the forcing cone. I'd reduce the load and see what happens. If no jams occur, I'd say that is your issue. Might also want to check to see if the crimp is sufficient!

 

[drumsetdrummer]

I appreciate the replies. I am using Hornady's loading data with Starline brass, CCI 350 primers, and up to 24.5 grains of W296. The locking started once I got close to 24 grains.

The PPU loads were factory.

The primers on the spent cases are all still flush and the cases don't wabble when placed on a flat surface. The primers have the normal dimple in them. All of the cases ejected easily - most with a single push of the ejector rod. And I pushed the rod while the muzzle was pointed upward.

I don't *think* the bullets were jumping the crimp. Once I got the revolver to unlock itself, I was able to keep shooting. That wouldn't have been possible with too long of an OAL.

I will pull the gun out of the safe later today and check for the ejector rod and strain screw per ken158's post.

 

[drumsetdrummer]

I forgot to mention I'm using 240 grain XTP's.

 

[Nightowl]

I hate to ask this, but could it possibly be "the lock"?

 

[drumsetdrummer]

The strain screw is tight. The ejector rod is also tight.

 

[drumsetdrummer]

I hate to ask this, but could it possibly be "the lock"?

The thought has crossed my mind, but did not want to go there first.

 

[stansdds]

The internal lock might be worth investigating.

 

[DWalt]

Good question, but yes it does it with some cheap but hot factory PPU loads. I have been working up a load starting from minimum and it locked up as I got near max. So that is why I'm thinking it only does this with hot loads.

I have problems with my 29-3 with hotter loads. My more pragmatic approach is to use milder handloads that don’t have problems. I have no need or desire for top loads anyway.

 

[chief38]

I appreciate the replies. I am using Hornady's loading data with Starline brass, CCI 350 primers, and up to 24.5 grains of W296. The locking started once I got close to 24 grains.

The PPU loads were factory.

The primers on the spent cases are all still flush and the cases don't wabble when placed on a flat surface. The primers have the normal dimple in them. All of the cases ejected easily - most with a single push of the ejector rod. And I pushed the rod while the muzzle was pointed upward.

I don't *think* the bullets were jumping the crimp. Once I got the revolver to unlock itself, I was able to keep shooting. That wouldn't have been possible with too long of an OAL.

I will pull the gun out of the safe later today and check for the ejector rod and strain screw per ken158's post.

An easy test for bullet creep is to measure all bullet's overall length with a pair of calipers, load the gun, fire 3-4 rounds and then see again with the calipers if the remaining bullets have "stretched". Remember..... reloading data is approximate - not an exact science! Powder does vary slightly from lot to lot. I have some Winchester 231 that I recently loaded 45acp rounds with. I've yet to chronograph them, however I'd bet this lot is a wee tad hotter than previous ones going by feel. Not a lot but enough to pick up on.

 

[Shotguncoach]

Is there a reason why you need to be at the very top end of the maximum load data? My 11th edition Hornady manual lists 24.5 grains of 296 as the red-highlighted maximum load with the 240 grain XTP. That doesn't mean that it's safe in your gun - it just means that in their lab, using their equipment, that load did not exceed the maximum SAAMI specs.

For contrast, the Hodgdon website shows 24.0 grains as the maximum for 296 with a 240 grain Nosler JHP.

Some pictures of the fired primers would be helpful. How round are the edges of the primers? Does the firing pin indent look round or does it have an edge that sticks up? You mentioned that the dimple looks "normal". Show us what "normal" is for your gun....

My best results with magnum loads have always been at between 90 and 95 percent of the listed max. You mentioned that the problem didn't start until you went over 24 grains. Try backing down to 23 or maybe 23.2 grains and see what you get.

 

[cmj8591]

I think your primers are backing out. It probably has more to do with the brass than high pressure. Sometimes the primer pockets are weak and don't hold the primer as tightly. It backs out and jams up the works. When you muscle the cylinder open, they get pushed back into the pocket so you don't really notice it. 24.5 of 296 is at the top of the loading data but the high end of that data is guided by the amount of powder that fits in the case with that particular bullet more than it is high pressure. You really can't get enough 296 into the case to spike the pressure into the danger zone. I run 25 grains of 296 with that bullet and it is superbly accurate out of my 6 1/2" Classic. So long as your gun doesn't have excessive end play, that is the cylinder doesn't move back and forth a lot when the gun is closed, I wouldn't send it back. Try changing brass and/or primers. You should be able to run that load without problems but you have to remember that it is a hot load and it requires a little bit more attention when loading. Be careful if you decide to back off the load and do not go below the minimum. As counter intuitive as it seems, that powder is more apt to give you a pressure problem with an under load than it is with an overload.

 

[drumsetdrummer]

"Is there a reason why you need to be at the very top end of the maximum load data?"

Yes/no. I bought this gun for deer hunting and it is a .44 magnum. If I find a load in the mid-range that is more accurate than hotter or milder I will go with the accurate load. But again, it's a 44 mag. I understand the S&W can't handle Buffalo Bore +P+ loads, but honestly, in this day and age, a gun should be able to handle at least a max load without locking up.

"How round are the edges of the primers?"
Normal as far as I can tell. I am trying to attach a picture but it wants a link. Let me figure out the picture uploading.