It's a DENSE little bugger .
And the only way to shorten it is to take the barrel off, it threads kind of like an Uzi, or M-3 Grease Gun.
The 2 pins only release the trigger pac.
The brace is just a rubber sleeve that slides over the buffer tube.
Is it legal to stuff that with paper to adjust Length of pull ?
I don't know when I'll get to shoot it, the local range is indoors, so it's been closed.