Re: Tunnel-rat's weapons.....
Being a scrawning little shit when I was in my late teens early twenty's I got "volenteered" a time or two to crawl down those slimmy rat holes.
I (we) used the 1911a1. I did see one guy carry a Browning HP for such work but I never seen him go underground with it.
Heard of some using S&W revovlers, but again never seen one.
I think your 22s and 410s are internet myth. No one in their right mind will take on such task with that crap. As to the 44 mag, that's a joke, the 45 ACP caused enough cave ins do to muzzle blast.
The thing is you're crawling on your hands and knees in mud sometimes up to your elbows, with a 1911 in one hand and a Fulton L shaped flash light with piss poor batteries in the other. You have to keep wiping the lense and shaking the big chunks of mud off the pistol.
I'm a revolver guy but there is just too many places where mud can sneak in and gum up a revolver. The 1911 just keeps on working, it doesn't care. The first round shakes off the offending mud and gunk that would jam up a revolver.
Heck most of the time you had to carry the 1911 hammer down couse mud and gunk could get under the hammer keeping it from hitting the firing pin hard enough to get it to go off.
We didn't have "desinated" tunnel rats. It was the smallest guy who was available. Its not for the faint of heart but none of us had the guts to admit were were too scared, we just prayed and went. Its not for the faint of heart, and let me tell you I WAS FAINT OF HEART but was too chicken to admit it.
When we ran into tunnels its better to be a '60 gunner, you get sent down the trail to provide security.
Best bet, go to OCS, they don't send officers into tunnels.