I just got an m14 and was wondering if chopping the barrle to 18.5 inches causes any changes in accuracy?
It can if you don't have the barrel recrowned. My one shorty was done by valley gunsmithing and it shoots just as well as before.
Also would it change the effective shooting range of the rifle?
Well you loose velocity with a shorter barrel so yes you do, but it depends on what kind of range you're talking about 100-200 yards no problem for sure, I don't have the data for further out you'd have to get some numbers figured out. With a muzzle velocity and some ballistics tables you could get a pretty good idea of what's going on.
Also, what are the benefits of chopping the barrel?
It's SHORTER
And the last one, is it possible to get an aftermarket 18.5 inch barrel that would improve accuracy and/or range?
YEp buy a krieger barrel for $600+ and get it cut down
I shot my m14 for the first time today, and im hooked, im going to try and get my hands on another one!