Hmm, confused now. Most of the tc data shown in my book is still under the 1.600" max overall length for the cartridge, I think only one or 2 loads exceeds it. If i remember correctly I measured my cylinder on my ruger at around 1.700" I'll have to double check. If i use the data i will start at max end of standard pressure data and work up slowly and cautiously, watching for excessive pressure. I am specifically looking at Unique and want to use the 300 grain xtp at between 900-950 fps. Thanks for the thoughts guys, maybe I should consider getting a .454 casull...