Re: barrel length
I've got a 4" Police Positive Special. I've also got a Dick Special 3" barrel. Bought it with intention of doing a barrel swap. Discovered that the shorter barrel will require a shorter ejector rod, also.
If you cut, or replace with a different one, your barrel from a 4 to a 2 inch, I believe you will also find that the gun will look funny unless you also replace the rod.
Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297
I always take precautions.
Beware the Evil Bullet Fairies.