Thanks Jimlad, that now gives me a good idea of what to make. To get the correct dimensions I will need to scale up the pics with the actual dimensions of my G79 muzzle.
This may be a bit of a long shot but if anyone has a G79 in pieces for spares and a foresight they would like to sell me then I will purchase it - would certainly save a lot of effort in making one!
Aubrey