Thanks Curl,

I did experiment with the patch length and I have it set so I can chamber the round without too much force.
Having read a lot about PP and from past experience with a .303, I've got a fair idea of what's needed, but I'm always open to suggestion :-) That round that I photographed may not be representative, it may be one of the first pressure test rounds that I fired into my bullet trap in the workshop.

Daryl,
When I first cast the 40-300-CSA bullets, I used my old standby of 50:50 Beeswax:Superfry and got reasonable results, but got better grouping with Lee liquid Alox. The reference to poor grouping with the FB bullet was from my home made moulded 405g PP bullet. I'll not bother with any more of them in this rifle, but I have opened the mould out to .408" and I want to try them paper patched in a .416 Rigby rifle.

As you may have gathered, I like making my own shooting equipment and ingredients and I think that I'm going to have a very entertaining retirement, when the time comes.