You should check out the air rifle crowd. They have pcp air rifles that will shoot a .172 lead 26gr bullet over 950 FPS with “lead dust collectors” on the end that make em real quiet and completely legal. Search 17hmair and tofazu on YouTube for a video of a guy striking a squirrel right through the heart from over 100 yards away. You have guys shooting .458 440 gr. Bullets at over 950 fps and guys able to hit a 30” steel plate with a .257 bullet in a air rifle. I’m building one now in .172 to accompany my 17 rem ar for anything in too close.A .177 pushing 1200+FPS out of those new model break-barrel Gamo's, right to the head will kill a lot of things dead. At least those are the velocities advertised in the Cabelas catalogs. Diesel that shit with a spritz of WD-40, you can get 1400+FPS. Though I heard that is quite rough on the barrel...