How common is crimp-jump?

[jashobeam]

I would like to know how many THR members have witnessed or experienced crimp-jump in revolvers. Crimp-jump is the action of the bullet (the projectile portion of the cartridge) becoming unseated from its original and proper position within its casing, causing the overall length of the cartridge to increase as more of the bullet is extruded from the case. If the term "crimp-jump" is incorrect or my definition insufficient, please feel free to correct either or both.

What I am specifically interested in ascertaining is the commonality of revolvers' actions becoming frozen due to crimp-jumped bullets being wedged against the frame and thus preventing the cylinder's rotation.

I want to know:

Have you ever noticed any amount of crimp-jump?
Have you ever observed a gun freeze-up as a result?
With what caliber and brand of ammunition did this occur?
With what size revolver did this occur (snub or full-size)?
Is this more of an issue for small, light, heavy-recoiling Airweights?
Is this a cause for concern?

Many people speak of the revolver's reliability and how it isn't susceptible to jams or malfunctions. A jam of this nature at the wrong time could be a real problem.

Twice I have witnessed crimp-jumping. Neither time was I the shooter. The first time, the cylinder was jammed up tight due to the bullet's noses leveraging against the Ruger SP101's frame (thankfully so, as the previous shot had been a squib resulting in a bullet lodged in the barrel ). The shooter was using someone else's reloaded .38s. The second experience involved an S&W 642 .38 Special with Winchester WinClean ammo.

 

[Majic]

Yes I have seen it happen. Generally it comes from a reloader not applying enough crimp to his loads, but lightweight guns using heavy recoiling loads can also cause it if the crimp was not applied firmly enough. That's why some of the exotic lightweight revolvers have had ammo restrictions.

 

[Biker]

Yes. If I don't heavily crimp 260gr bullets for my Taurus 450, I'll get an occasional crimp jump. No problem with the lighter bullets.

Biker

 

[Lone_Gunman]

I have never seen it happen. The two examples above were the fault of inadequately crimped reloaded ammo.

Has anyone ever seen this with factory ammo?

 

[capbuster]

When I bought my first Smith and Wesson md 29 back in the 70s, I had some bullets move out from their crimps while firing a cylinder full of cast swc bullets,lyman mold number 429421, and heavy loads of 2400 powder. It did not tie up the revolver but some of the bullets did ease out a bit.I moved on to other powders and lighter loads and have not had a problem since.

 

[atlctyslkr]

Happens in Scandium 357's alot. That's why I don't own one.

 

[bakert]

i've never had it happen to me, but saw it twice with friends of mine at the range. One a Ruger Super Blackhawk, and the othe friend's 629 S&W. Those two instances were both caused by insufficient crimp with heavy .44 magnum loads.
With the small snubbies I stick to the reccomended ammo because some bullets, especially lead in the lightweight guns will jump the crimp lots of times according to what I've read. Also in all handgun loads, bullet pull with reloads is as important as the crimp in my opinion. The bullet should be tight in the case before crimping.

 

[jashobeam]

Has anyone seen it with factory defense rounds?

Hey, everyone. Thank you for your replies. I believe that severe crimp-jump is a rare occurence, especially with factory loaded ammo. The range I shoot at rents many types of pistols and revolvers. I have never seen or been told of one of the rental revolvers malfunctioning due to crimp-jump with the factory ammo sold there (MagTech, American Eagle, Independence).

I have never seen it happen. The two examples above were the fault of inadequately crimped reloaded ammo.

Has anyone ever seen this with factory ammo?

The second experience involved an S&W 642 .38 Special with Winchester WinClean ammo.

FAQ: What is the difference between WinClean® and standard USA ammunition?
WinClean® is loaded with BEB bullets and lead/heavy metal free primers to provide a product that virtually eliminates airborne lead exposure at the firing line.
http://www.winchester.com/contactus/faq/faqview.aspx?questionid=54&question=&history=0

The reason I posted the FAQ is because I have for a while thought WinClean was substandard ammunition. LoneGunman's post made me wonder if in fact they were reloads. Now we all know the difference between WinClean and standard USA ammunition.

Has anyone ever seen this with factory defense rounds?

 

[RecoilRob]

Charter Arms Target Bulldog would regularly move factory bullets out, sometimes the last round would be out far enough to jam things up.

Never had a problem with my reloads but they were heavily crimped. Seemed the factory (Remington? Been a long time ago) wasn't thinking they would be used in a 20oz. pistol.

 

[Lone_Gunman]

LoneGunman's post made me wonder if in fact they were reloads.

Ooops, sorry, I didnt see the statement about Winclean, and thought all the examples given were with reloads.

 

[Working Man]

Randy Garrett warned me about it happening with the heavy faster .45-70
rounds in a BFR since they are not even crimped. The CUP is within tolerance
of the BFR but I was warned not to use them because of that issue. I have
used rnds that are 15 grns lighter traveling 50 fps faster and have never
experienced it myself though. Perhaps that does not happen due to the
overall weight of the gun and my grip being rather solid.

A question for those that heavily crimp their reloads. Could heavy crimping
cause other problems due to excessive pressure building up in the case?

 

[orionengnr]

Happens in Scandium 357's alot. That's why I don't own one.

care to substantiate that statement?

 

[JohnKSa]

There was a thread just a day or two ago by a fellow shooting Blazer aluminum case ammo in a small revolver and having crimp-jump problems.

 

[Master Blaster]

I noticed it with the Corbon .38 spl +P 110 grain jhp rounds when I fired them out of my 642, fired three and went to do a reload looked at the other two and they had significantly jumped the crimp.

I also used speer and federals out of this gun and they did not jump crimp all were 110 gr +p.

When I called corbon they told me it was normal, buth they would send me two boxes if I sent the one I had back. I declined their kind offer.

I carry speer 135 gr short barrel gold dot +P and I have loaded 200 of them myself using speer data for universal clays and speer bullets from midway for practice, and they have not jumped the crimp in my 642, apparently Corbons crimp die doesnt work as well as mine does.

 

[Logan5]

I haven't experienced it, but I don't reload and I rarely shoot commercial reloads. I run through a lot of .357 and a bit less .44 magnum and special, but I haven't encountered this phenomenon myself. Then again, I don't go above a 200 grain bullet in my 296 because S&W tells me that's what will happen if I do.

 

[HSMITH]

I have seen bullets jump crimp several times, and once locked the gun up pretty hard. All were with very heavy loads and/or light guns that recoil quite hard.

 

[New_geezer]

Had it happen in several batches of practice 357 reloads bought from the local gun shop. They've since switched reloaders and haven't had a recurrance.

 

[loud-mouth shnook]

Never seen a forward jump, BUT...

...I've had bullets setback deeper into their cases in my marlin 1894CS (.357 MG). They were all Federal Subsonic 158 gr. JHP .38 spl.+P. Obviously not meant to be stuffed down a tube mag. I'm sure in a revolver, their intended application, there would have been no problem.

 

[Imaginos]

Handloads

I've had a few of my handloads jump the crimp, but never a factory load.
All of the jumps were with swaged SWC, and it was my fault for not leaning on the handle hard enough when I was crimping them.

 

[Phil DeGraves]

I have seen it happen with FACTORY Remington 44Spl 246 grn lead RN in a S&W 624 revolver. It never happened with any other ammo including reloads.