Re: What is the most powerful (commercial) .22lr?
CCI High Velocity MiniMags are one of the few rounds that will reliably cycle my ammo finicky Beretta Bobcat 21a so they should have the power for your carbine?
As to using it for steel targets? Yes, it will knock down ALL steel targets designed as .22LR knock down targets at the distances advertised. Those designed as centerfire pistol or rifle knock downs require those calibers to operate. Basic physics is basic physics and that's why they call them Laws - lol
Lee Anniversary and Lee Classic 4-Hole Turret, presently reloading .380, 7.62 Nagant (32-20), 9mm and 45ACP