View Full Version : Blowback Issues

ross * pilot
04-06-2007, 12:26 PM
Hey guys,
Even with purchasing a 2 oring ACP bolt, and making my gun LP, while operation at 300 psi, im still getting some pretty bad blowback. Each time i fire, all of the balls in my plastic feedneck go straight up. Because of this, im not confident of shooting fast, in that i might end up with a blender. Even when i am shooting slow, 1 paintball at a time, sometimes a ball breaks in the feedneck, no paint in the barrel or on the face of the bolt. Its pretty frustrating. I am going to purchase a new feedneck soon, will that solve the problem?

04-06-2007, 12:47 PM
Two questions. First, what fps are you shooting at with 300 psi and, second, what feedneck are you using now?

04-06-2007, 12:50 PM
AND........What hopper are you using??? If its a HALO, no balls are going to move back up bc pressure is being forced down from the Halo.....

ross * pilot
04-06-2007, 12:55 PM
280fps. im using a revvy. stock feedneck.

04-10-2007, 12:54 AM
I had the same problem when I swapped all my LP parts over to the new Pilot body (purchased only a new Pilot body).

There must be a slight diff in the valve screw/ air hole location from other guns cause soon as I swapped the parts over I got massive blow back. I put two balls in the feed neck with no hopper on the the second ball would blow out some 15' in the air, not good for repeated shots with any hopper.

After spending tons of time trying to figure out why this was happening I finally nailed it down. I measured the bolt from end to the rear most o-ring and discovered when my rocket valve was opening/open the air hole wasn't centered over the air hole in the Pilot body. This was letting air split the front o-ring and blow out the neck. This same problem was also killing my FPS since I was only getting about half the air actually going through the bolt hole. I adjusted my dwell on my Rocket Valve almost all the way in and sanded the nipple off the hammer till it was flush, this mod allows the bolt to center over the air hole as the valve opens making all the air go through the valve vs 1/2 out the feed neck. Ideally the hammer should come as close as possible to the pin that's pressed into the body just in front of the valve, this will also help you get the best blow back for recocking. I also run Dow33 on my o-rings for a better seal.

Jim Lewis
04-12-2007, 04:52 PM
Dont want to hi-jack this but would you mind explaining this in further detail. Specifically what and how you measured it. I have the same thing with my pilot.