the 32ACP is a semirimmed round, (the diameter of the rim is larger than the body)
The magazine stacks the rounds with the rim of the upper round foward (towards the chamber), thus the rim of the round being loaded will slide over the body of the next round in the magazine.

...[----->/
..[----->/
.[----->/
[----->/

IF the rim of the top round gets behind the lower, the top round becomes locked and can not be pushed into the chamber.

..[----->   /
...[----->/

to prevent this condition from occuring the inside lenght of the magazine is made to be a snug fit with the overall lenght of the round.  This worked well when there was only military ball ammo, however the lenght of rounds now very, especially the JHPs.

With the overall lenght of most JHPs being less than military ball, with a magazine that accepts ball, the shorter lenght JHP rounds can lock.  Some pistols have magazines that only accept the shorter  JHPs.
....[----->/
.....[---</
....[---</
..[---< /

the KT magazines will accept military ball, therefore to prevent rim lock if you want to use JHPs, a spacer must be added to fill the magazine.  a spacer called the Flyer Wireor a kit from KT can be used

 

I believe that rim lock can only occur while loading the mag (improperly). Can anyone explain how one round can jump up while the round below moves forward , all the while under pressure from the mag spring , and the top round restricted from moving up by the slide and mag lips??? Not just theory ....I want to see the mathematics and the physics principles defined , with empirical data to support the claim....


Jerrittcat....who's a rim lock sceptic.

 

i had a lock up on wwb a couple of months ago...i took me a minute to realize what happened...what or why i don't know....but is does happen on fmj, that i can atest too...gpr

 

I believe that rim lock can only occur while loading the mag (improperly). Can anyone explain how one round can jump up while the round below moves forward , all the while under pressure from the mag spring , and the top round restricted from moving up by the slide and mag lips??? Not just theory ....I want to see the mathematics and the physics principles defined , with empirical data to support the claim....


Jerrittcat....who's a rim lock sceptic.

 

Can anyone explain how one round can jump up while the round below moves forward , all the while under pressure from the mag spring , and the top round restricted from moving up by the slide and mag lips???

Very simple.
It's called recoil!

All kinds of strange things happen to the rounds in the magazine when you hit an 8oz gun with 125+ fp/lb's of muzzle energy.

And rim-lock is not just theory, it is alive & well in .32 ACP pistols using short JHP ammo.

It just had not been much of a problem in all the blow-back operated .32's like the PPK Walther, Brownings, and other guns. They all have to have relatively heavy slides to absorb the recoil impulse.

The P-32 is different, because it is the only locked-breach .32 ACP now being made.
As a result, the slide is very light, and it doesn't have enough mass to power through a rim-lock that other guns would shrug off.

Believe it, cause it is a fact!

rcmodel

 

i had a lock up on wwb a couple of months ago...i took me a minute to realize what happened...what or why i don't know....but is does happen on fmj, that i can atest too...gpr

WWB has a truncated flat-top design ..not quite the same as normal round nose fmj

 

I've had it occur with ball ammo.

 

I have read a lot about rim lock on this board but never experienced it, until yesterday. My wife and I were at the range and when she tried to fire the first round out of her Gen 2 P32, the top round would not feed it just stayed at the top of the clip. I took the clip out and tried to unload the clip but could not. I said "Aha!! this must be rim lock!!" Took the clip apart (the only way to unload it) and looked at the top most round. She was firing a mixture of FMJ Remington and S&B in that clip. The Remington had a thinner rim than the S&B. I loaded the mag up with just S&B and no further problem. Rim Lock is real and it can turn a good pistol into a paperweight in a hurry.

 

Here's the obligatory link to the yzguy site which has a comprehensive explanation with pictures:

http://www.1bad69.com/keltec/rimlock.htm

 

Soo....now that we know it happens. How rare is it? And what can we do to minimize the chances? I had heard carrying FMJs in the magazine eliminated this issue, but apparently that is not the case.

 

FMJ generally does not cause rimlock because it usually has a long enough overall length (OAL) that there is not enough room in the mag for one round to jump in front of the other. But some FMJ are shorter than others, especially those with flat noses, and that could create a potential for rimlock. But if your rounds are long enough, then you don't have to worry about rimlock.

I use Fiocchi FMJ in mine, and there is not enough room in the mag for one round to jump in front of another. But I am still very careful when I load the mag and I make sure that every round is firmly seated against the rear of the mag when I put it in, then I tap the mag against my hand when it's fully loaded.

If you are using rounds that are short enough to cause rimlock issues, then you could probably benefit from an anti-rimlock kit.

 

I keep a hollow point in the chamber and another at the top of the magazine, the rest of the magazine is loaded with FMJ. I do this to minimize the chance of rimlock and I like FMJ in the .32ACP for better penetration.

 

+1 on the HP in the pipe and FMJ in the mag. I don't think rimlock is rare. I have experienced it, as have others on this board. Fortunately, I haven't heard from anyone who experienced it when in a defensive situation-- but we might not ever hear from them again. I've made flyer wires. They are very easy to make and work well. But why bother? FMJ is the way to go INMO. I'll continue to load a HP in the pipe until I run out of them. Fiocchi makes a hot FMJ round. I think that's the way to go.