It's not the 80gr TTSX, but I use the 85gr TSX bullet in my Marlin XS7 with 22" barrel. They seem to really hum out of it pretty nice..
44.5 gr Hunter = 3125fps, 45.5gr Hunter = 3274fps, 46.5gr Hunter = MAX per Barnes - didn't try it. OAL 2.676" which is a little longer than Factory loads.
I also have loaded up some using H414. 43gr = 3256fps, 44gr = 3308fps. USE AT OWN RISK, AS THERE ISN'T PUBLISHED DATA FOR H414/W760 WITH 80GR BARNES TSX. Data based on Hodgdon / Speer / Lyman manuals for other 85gr bullets which suggested 45 - 45.5gr was max for their 85gr bullets.
Both shot good enough for game, around 1" at 84 yards (that's as far as the range I go to goes).
Hope to get a chance to try them out on some GA Whitetail in about 5 more weeks.
