357 mag crimp jump

[dmr2400]

Has anyone had issues with crimp jump (bullet creep) with factory ammo if so how do you fix this I am see this in my GP 100 4in 7shot using PMC 158 gr ammo.

 

[buck460XVR]

Never had an issue with crimp jump in any factory revolver ammo. What kind of bullet and velocity?

 

[paul105]

Some years ago (don't remember how many but probably 10+) - had this happen with Magtech .357s in a S&W 386.



I just reseated/recrimped them and recrimped the rest of the box - worked fine.

Paul

 

[shoebox1.1]

How would you know this was happening unless you opened the cyl after every shot?

 

[dmr2400]

The gun jammed and I could not cock it

 

[243winxb]

For factory ammo, contact the factory/maunfacture for exchange or credit.

If your a reloader, pull bullets, size brass, reload.

Bullet jump tends to happen in very light revolvers. My 10 oz 38 spec +P came with a warning inclosed in the box.

 

[buck460XVR]

The gun jammed and I could not cock it

Yep....that would do it. Means there was some pretty excessive jump going on. The GP-100 is not what I would consider a lightweight gun for the caliber, but the PMC ammo, going by published velocity, is pretty stout. Can you see the roll crimp? Many times with factory ammo, the roll crimp looks more like a taper crimp.

 

[Steve C]

Such issues are usually a result of firing lightly crimped heavy bullets with heavy loads often from a light weight firearm, however as buck460XVR remarked your GP100 wouldn't be considered a light weight. As this is a problem of recoil inertia you may be able to mitigate the problem by resisting the recoil movement with firm grip and locked wrist.

On the rare occasions when I've had this issue in factory ammo as a hand loader I have simply crimped any unfired rounds with a heavier crimp. Those that had jumped their crimp simply got the bullet seated back to a proper depth and crimped. If you are not a reloader but know anyone who hand loads ask them if they can add a slightly heavier crimp for you. It is likely that the factory had produced some ammo with insufficient crimp that you just happened to purchase. If it was a common problem with their ammo I am sure there would be many complaints on the internet.

If you have a case of this ammo then a complaint to PMC may be in order but for a few boxes of ammo it is hardly worth the effort of boxing it up and mailing back to the company for replacement. I would first try changing my grip and resistance to recoil jump to see if that didn't work and if not look for someone who could crimp the bullet some more. After which I'd try a different brand of ammo.

 

[george29]

Yep. Locked up my revolver at the range. That's why I carry a back up. When a revolver fails it's usually something that needs time & tools.

 

[gotboostvr]

I've had the exact same problem, with the exact same ammo. I was shooting a 4" M19-3 and that ammo tied it up EVERY time, a couple different lots too.

 

[walterelm]

Years ago i had the same problem. Zylinder locked. Went to dealer ... showed him the ammo ... you could see it was getting too long ... he exchanged all boxes ... i insisted on a different lot ... took him a while ...but no problems afterwards ..

 

[ThomasT]

Yep....that would do it. Means there was some pretty excessive jump going on. The GP-100 is not what I would consider a lightweight gun for the caliber, but the PMC ammo, going by published velocity, is pretty stout. Can you see the roll crimp? Many times with factory ammo, the roll crimp looks more like a taper crimp.

You probably nailed it. My bud had some factory 38s that were just taper crimped instead of having a good roll crimp.

 

[mjsdwash]

if you have a lot, look up a reloading class in you area, and see if they can crimp it for you. Otherwise, your stuck with the factory response. You can push the bullets in and stab crimp, but thats not straight forward.