Looks pretty good, I have some nitpicks below.
Lighting kinda sucks, put it on a background that makes it pop, it's hard to see if some of the details are right
The hammer and sight look simplified (bits that should be rounded, or cut out), also I don't know the proper term (slide, I think?) but the top of the gun where there's metal triangle cutouts and stuff, your model needs to be sharper there; shit's supposed to be press cut metal like done with a machine not with a handle file
The patina doesn't look authentic, for example there should be pitting where it was fired