Quite a few years ago, I decided that a mouse pistol might actually have some redeeming value.
I had gotten it into my head that they could be concealed regardless of what you were wearing, and could provide some sort of armament in situations where carry of a real gun wasn't possible.
So, I bought this cute little Jennings .22.
I quickly found out that "POP POP JAM" was good... because it would often fail before it got that far along.
I tried all sorts of different bullets in it, and found none that were any better than the others.
It would light strike, feedway jam, refuse to return to battery, stovepipe, fail to extract, and very rarely would it manage to fire the whole magazine full of bullets.
"But if it actually WORKED, it would be COOL!" I said.
I decided I would fix it. I ground on the feed ramp, put a radius on the mouth of the chamber, and tweaked the lips of the magazine until I finally found a combination that would actually pretty much put the bullet in the chamber.
"POP POP POP JAM" My buddies all laughed at me.
I enlarged the ejector port, and welded up the extractor so I could forge it flat and grind a bigger stouter hook on it. I cut the frame to allow my super extractor to get in there and grip the case. I got it so it would pretty much get the empty case out of the way.
"POP POP POP POP DUD" My buddies all laughed at me.
I tweaked the striker and it's spring for a better hit on the rim.
And then it started working! COOL!
I could load five or six rounds (I forget the amount, but it wasn't many) in the little magazine, and then shoot it empty.
"POP POP POP POP POP POP"
By this time, I had shot the tiny pistol enough that I could actually pretty much make the bullets go more or less where I wanted them to go.
My buddies stopped laughing, and started in with the "Yeah, it fires, and yeah, you can sorta hit with it, but that .22 round is a PUNK and will only piss 'em off!
I was standing maybe 15 yards away from a steel 55 gallon drum at the moment. I said "Watch this!" and proceeded to pop a magazine full of bullet holes in the steel drum. "POP DING POP DING POP DING POP DING POP DING POP DING"
My buddies said "Hey! Let me shoot that thing!"
We passed it around, and shot up a whole box of bullets without a single failure.
Everybody was duly impressed, and agreed that a mouse pistol that actually worked just might be sorta OK after all.
And all was well... until the very next time I tried to shoot that pistol.
It seems that the slide on that thing was cast out of Zinc, or some other "Pot Metal", and it was pretty soft.
When I got it to reliably feed, and started shooting mag after mag of bullets through it, I drastically exceeded it's design limitations.
The breech face started peening, and it got so that it was pinching the firing pin where it protruded through the slide. Now it was a fixed firing pin.
It took me completely by surprise. I loaded a mag full, stuck it in the pistol, chambered a round, pointed it at the target, and pulled the trigger.
"RRRRRRRIIIIIIIPPPPPPP!" and it was empty!
HOLY CRAP! Fortunately, all it did was empty it's self and no damage was done.
I took it apart, and figured out why it was suddenly a machine gun.
When I saw that it was smashing the breech face, I destroyed it with a hammer.
So, that's why I feel like cheap mouse guns are something I wouldn't want.