Piper and Chuck. Let us say that we are two Nations separated by a common language. It is sometimes difficult to explain in few words exactly what is meant . I have recalled mistakenly it seems that Piper had said he was engineer .
Paralleling is a term used in the British gun trade meaning the barrels are put together so that the muzzle is in the same horizontal plain as the breech. In tests we carried out some years ago using lasers mounted inside the bores of variety of barrels from Purdy's to Midland Gun none of them had over lapping patterns at 30 yards. Lining them up on a target as you would sight a rifle down the center of the rib they all centered high with the right barrel being left of center and the left barrel being right of center.
This showed that the barrels were not "regulated" as some people seem to think . Some makers of O/U clay guns have made attempts in recent years to address this problem by spacing the muzzles and using a very high rib .I'm sure you will agree that a SxS built like this would be an ugly beast looking like a clumsey double rifle. Several O/Us, B25 Miroku and a Boss, we tested at the same time all tended to center top barrel flat and on mark bottom barrel high . This was proved shooting solid slugs.
This is the basis for my maintaining that gunmakers did not "regulate" barrels as some believe, the only regulation was to shoot a set pattern at a set distance with a specified cartridge .
It came as a surprise to me as I had always understood from being an apprentice that the average 28" double SxS had overlapping patterns at 30 yards
Based on our findings I then worked out a mathematical formula , which proved our results. I hope this clarifies things .
