All u need is a vise, a center punch, a punch and a hammer. there a real snap, you can do it in ten minutes. Put the piston in the vise in an angle with the rear of the piston sitting ontop of the vise jaws and crank down. Find the spot (hole) where it is connected. Beat a center punch right on that spot and the little pin will start to move, take a punch and drive it out. Unscrew it, then screw the new one in, leave a little wobble to it. Take a piece of 1/8 drill rod found at any hardware store, put it in the hole, cut the drill rod so about an 1/16th - 1/8th is exposed on both sides. Now lay the carrier on the anvil part of ur bench vise, rest it right on one of the exposed sides of that protruding drill rod and smack the other side with a hammer, turn it around and smack the other side, this will fill in the bevel around the hole. Clean up with a file or the dremel and your done. I usually put a small tack weld on it but its not necesary. Dont build the whole rifle then let the little piston scare you. just take your time, you'll be fine.