If you want it to work like a sniper you need to disable blowback and cut a slot in the top of your hammer. The slot allows the bolt to stay cocked wile you move the bolt forward. You will need to remove the o-ring on the bolt. I did this to a Spyder and it's a lot of work but turned out very nice.
You can also cut or remove the link between the bolt and hammer. This leaves you with a gun that automaticity cocks the hammer but you have to manually cycle the bolt. It's less efficient, but i imagine a lot smoother to pump. If you do this be sure you have a way to manually cock the hammer.