You appear to have a very well equipped workshop that is better than the average hobbyist or model engineer.
Did you make the sling swivels on a former or did you do them in a die on a fly-press? I know from experience that bending something like that by hand is very difficult to get even on both legs/sides.
The barrel appears to have Belgian proof marks and the bore at 18.8mm. Why was it necessary to have it reproofed?