Interesting. I shoot a 142gr PB @2100 fps, just haven't gone any higher (18" 1:10 barrel, carbine gas). Works fine in the 10" 1:8 pistol too. Performance is just a tad below 150gr. in 30/30 min load. I did look at 40WT but the neck is short. I formed some with BO sizer and made a longer neck for cast. Would also get rid of the really long throat that I don't need. Anneal the neck and expand in steps. Don't have QL so I can't evaluate the performance with slower (223 type) powders. Testing some 170PB & 185 GC RDish in the pistol. Actually hit a pig but it ran off so no conclusion. Back end of a pig in the bush isn't easy when they are moving. Just got back from a jaunt to LLano & San Saba (really cool little town) but hope to get to the range tomorrow for more testing.