Cwillard,
See this for a good write-up of the XTP:

http://www.chuckhawks.com/underrated_hornady_XTP.htm

My son uses them and one of my buddies, they are excellent bullets. I have read where the jacket comes off when shooting hot loads (150g).Some like the 240g and 260g, I like the 300g since they go thru the deer, whereas the 240 don't. I live the price of them bulk, $14 for 100. Ishoot them all the time for practice instead of Nosler Partition (which are $1/bullet). I like themwith the Crushed rib sabot in my FL, my Knight Disc and my TC Omega. Most gun manuals have loads for the XTP, my FL does, my Omega does and the Savage does. So they are popular and good. If you buy this book on modern muzzleloading:

http://www.amazon.com/exec/obidos/tg/detail/-/0873419510/qid=1114882877/sr=8-1/ref=sr_8_xs_ap_i1_xgl14/002-8867395-7390420?v=glance&s=books&n=507846

Chapter 9 is on Deadly bullets, and the author, his son and his buddies mostly use the XTP. Anyway it is a great read. I don't honestly see the purpose to the Lock and load with a speed loader and using pellets. Waste or time and more costly in my opinion, so why do it, you never need the 2nd shot anyway 'cause you boom flooped the first shot. Just my opinion ona bettermouse trap. Good hunting.
Chap Gleason