Another little piece of the puzzle I was playing with today was the barrel mounted sling eye. Thanks to Sarg
As mentioned earlier I got a couple of these posts

So with an off cut of shotgun barrel which just happens to have an ID that is almost the same as the OD at the appropriate place half way between the end of the forestock and the end of the barrel.

From a centre punch and pilot drill hole I marked the desired outline of a circle and bored the required hole in the barrel to take the cut down stud.