I can do no more to convince you than ask you to watch Brett Gibbons' latest YouTube post - a tale of two Whitworths....I've included my preamble from the Whitworth Collectors' page of FB - yesterday, coincidentally, was Sir Joseph's birthday. I bought my first P-H Whitworth [#888] in 1986, and second ]#420] in 2022.
'Happy Birthday, Sir Joseph! And to celebrate the event, here's Brett's latest YT production with a debut of a 1980-made Parker-Hale Whitworth, the very first shots EVER from this iconic rifle, showing clearly why they are so valued by the cognoscenti - that is to say, us poor folks who can't quite step up to the heady finances of a genuine article. Brett is shooting his EuroArms with less success, but with just as much fun, no doubt.'
Please note that the hexagonal Whitworth rofling is NOT progressive. The bullet, if a hexagon, is a fit for the rifling with a turn of, I bleeve, 1:20, and makes a perfect fit on firing. A cylindrical bullet like the multi-groove Lyman, turns into a hexagon with the help of between 70 and 90gr of 3Fg. Both shapes work perfectly well. You can clearly see the six-sided holes in this target, shot with my original rifle many moons ago -
This is the first ten shots with #420, last year. Again, the bullets were round and the holes are hexagonal....
and here is the rifle...