My .243 M788 loves those little 55 gr. BT's! It is a 1-10" I thought the same as you, bought a box for fun cause I was bored, filled the cases with 53.0 gr. of H380 and went to the range. My first shot hit the target 2" high, dead center, same as my 100 gr. Partition load. Third shot touched it, third shot made the hole a little bigger, then so on and so forth. The are a great indicator of when I've shot my .243 too long without cleaning it, if the accuracy drops of to over and inch, it's time to clean. I love the bullet, I've considered using the 70 gr. for long-range shooting, then I bought an Encore and decided to save up for a .243 AI and will reserve the 70gr. bullets for the AI version. Shoot and have fun, the make mincemeat out of gopher/p-dogs and coyotes are leveled on the spot with a good chest hit, and sometimes it doesn't come out. My farthest shot was on an unamed predator at 642 yards. This predator was feeding on one of my chicks it had just flown away with and made the mistake of letting me see it and stopping within range. It's my farthest shot ever, but it was a one-shot-feathers-floating-down result.
Selmer