I'm curious how so? No disrespect,just wondering.I only say this because I have a regular 375CT.The problem I find with the cartridge is the lack of suitable modern powders giving proper load density to achieve proper "efficiency".Even a max load of Retumbo (134 grains) behind a 350 Jamison is 1/4" below the shoulder.I'm assuming load density would be a worse problem on the improved case. Maybe I'm wrong?
I've had slight hangfires with R-25 which I feel is too fast of a powder for the 375CT and have had hangfires with some of the really slow 50 BMG powders.No problems with Retumbo,US-869(very temp sensitive),AA8700 which is no longer available.I think the 375CT case is already on the very edge of what a large rifle magnum primer will reliably ignite as is,let alone an improved version.
I enjoy wildcat and/or AI type cartridges myself.Of course the other cartridges are standard sized,6mmART40,30-375R,6x47L and others I've owned over the years.With them it's no problem finding the perfect powder and yes they are very efficient.
Thanks,
Steve