I just bought a Spyder Pilot ACS a few days ago and because I heard a lot of differing opinions on whether or not the acs bolt actually works I decided I was going to have to test it myself. For anyone who doesn't know the acs (anti chop system) bolt has a spring in the bolt which causes it to compress if it encounters an obstruction i.e. a ball not fully chambered. That way instead of slicing the ball in half the bolt simply recocks, and the ball falls into the chamber unharmed and ready to be hurtled in the general direction of your opponent (or a teammate's back if you're a noob and not paying attention. I hate that

!!)anyways...
To test the bolt I took some paintballs (draxxus blaze) and hot glued a piece of string to the top of each one, and then hung them halfway down into the chamber and fired (co2, not dry firing). I did this with 8 paintballs and had zero chops. One ball I actually smacked with the bolt 7 times (until the string broke) and when I pulled it out it was completely undamaged. This is with the aluminum acs bolt that comes stock in the acs edition of the Pilot and Fenix. Not even the aftermarket delron version. So if someone tells you that the acs bolt is worthless, or just a gimmick they are LYING. It works exactly as well as an eye, is much cheaper, and will fit any spyder (don't knock spyders, there great reliable markers for people who don't have the finances to pay $600-$2,000 for a marker. If I had that kind of cash I would, but I have other financial responsibilities (car, school, etc..). So if you are looking for an ultra reliable marker, put an acs bolt in your spyder and get ready to never again need to field strip in between games because your receiver is filled with goo.

PS: I have nothing against noobs, but friendly fire is NEVER friendly, check the armband!