Hello Barry,
(BTW: Reply to your PM sent)
"......How goes the loading?...."

Well, not very quickly as I have (stupidly on my part) been at the mercy of RCBS and their handling of my order for a shellholder to fit the Bertram .577/.500 No.2 brass. (The shellholder was out of stock)
My only comments would be:
1) it has been since 3 March that I ordered a shellholder and posted a brass case to RCBS for testing the fit. Five phone calls and 3 MONTHS later the RCBS staff claim that they are posting said shellholder this week....oooops!
2) RCBS might have a great warranty.....but it just is not the company that it used to be. "Vista Outdoor", the holding company/owner, should be ashamed.
Fred Huntington would be apoplectic at the "customer service" these days.

I've been a loyal RCBS/Huntingtons customer for 40 years.......I think my loyalty has been tested enough and it is time to switch to CH-4D or Redding.

RANT ENDED....

At any rate I have loaded and shot 10 fresh Betrram .577/.500 No.2, 4 loaded with black powder, greased felt wad, and 340 grain PP as well as 6 NfB with 54 grains H4198, foam backer rod, and a 440 grain PP.
Only was able to shoot offhand at 30 yards but all shots stayed in a 6" circle.
Expect more info once I actually receive a shellholder........ :-((
- Mike