I made a discovery!!!!!

[Colt25]

I stumbled upon that 1/2'' cpvc and copper pipe fits snugly inside the main tube of the 13xx and I assume the 22xx.
I already made a stock out of cpvc. I call it the 'bendy.'
The only problem is that it doesn't prop your head up enough. So you need to hold your head up yourself
But no big deal.
Also, you will have to make something to hold the hammer spring or else it will not fire,
try all you want but it just wont work if you don't integrate a rear cap.

It works, but not the greatest.
Hope this helps someone,
-Colt