RH300UM
Well-Known Member
YepMy design is 3 cartridges based on the full length 416 Rigby Improved with .010" per inch taper, 300-416 Rigby Improved 40° shoulder with .331" length neck, 338-416 Rigby Improved 45° shoulder with .475" neck and 375-416 Rigby Improved 40° shoulder with .425" neck.
These gave me my minimum parameter with ease, which was a minimum velocity of 3,000fps with most bullets using my 8", 9" & 10" twists, respectively. I never made the reamer or barrel for the 30 cal version, there was just no suitable bullets at the time to match my 2,000 metre criteria. There are many now, but in the early 2000's there wasn't.
The 33XC is now a very close clone of my design, so is the 37XC, both have different shoulder angles, but are close.
Cheers.
Same here
Quality Brass supplier was the biggest issue
Then it was repeater vs. single feed and QUALITY actions that supported the idea to start it all off