This will depend to some degree on the barrel length. A 4 inch .38 Special revolver has an effective range of about 50-60 yards.
3 miles
1000 yds or so
38 cal colt's revolver sn 94764 what year was it made?
No
100-300
No.
Yes.
Impossible to answer without the maker's name
2015
1974
10-1000 USD depending on specifics