Thanks guys for yur comments.

Mick, using the work that Michael Pertov did in his firs 400 Whelen article in Precicion Shooting in 2001 the Whelen is going to have a 23 deg .458" shoulder starting right at 2" OAL is 2.47". I don't have his exact capacity. My case is 2.65" 40 deg shoulder .46" shoulder starting at 2.18". Using QL Brwon Whelen Capacity which I think is a touch greater than the Whelen do to shoulder position. My PDK loaded to the same OAL has a 8% net gain. However if you load to the OAL needed to use the cannelure on many 411cal bullets the net gain becomes more like 18%.

Daryl,
My gross capcity basically the same as the Taylor. However since my case in narrower and longer loaded to the same OAL with say 400gr bullets the Taylor has about 12% more net capcity. Less so with lighter bullets. Not to mention there ae more 416 bullets on the market than 410-411. I actually run 416Speer 350 grs through a sizing die and reduce them to 411 for a 350gr bullet n my 400. One big advantage I have over the Taylor is in a Mauser action it takes about 10 minutes to open the sides of the mag box in the shoulder area to allow me to get 5 down in a factory box.

I like your 375. My original case was an Improved 280 that I used from 243 up to 416. Here is my 380PDK using both the 280 brass and cylinder brass. From left to right. 375Whelen, 380PDK(280 brass) 380PDK(cylinder brass left at 2.60") 380Howell factory brass and 375H&H.

I had first used the 280 brass and when we built my buddies he wanted to be able to use the Howell brass.So we cut the neck longer to 2.6". I was loosing brass necking all the way up to 375 from 280 so I elected to switch to cylinder brass. American Hunting rifles actually sell, rifles, rechambers, sells ammo, brass and dies in the 380Howell. The shoulder is just a touch behind mine and they use a 30deg I believe. I also think they leave the shoulder at around .454"