Which way are you trying to knock it out? It’s supposed to be knocked inside out. Apply some PB Blaster and let it sit for a little bit. It is important to note that the spring steel pin that holds the stripper clip guide is slanted from the rear toward the front. Remove the action from the stock and tap the pin with a 3/32 drift punch until the pin can be removed from the bottom of the receiver. Rest the action on its left side and tap the clip guide from right to left out of the receiver. If you get the spring steel pin out, it should be no problem tapping out the guide. Once you have the roll pin out make sure you are tapping it in the correct direction. The clip guide drives in from the left and should be driven out from the right. Support the receiver on a block of wood and drive towards the left side. If the rifle is well supported and you don't hit anything but your driver with the hammer you shouldn't be damaging anything.