betterthanstudying

How much resistance should the plunger have if I'm pushing it? I'm in the process of making a gun that mixes the qualities I like from ompa's gun and the FAR, but after a few early test fires I found that I cannot achieve distances over 20 feet. I suspect my problems come mostly from the seal issues of the plunger and clip, which I eliminated with a lot of tape and by getting rid of all but needed components to fire(ie. the barrel, the spring, the plunger and bolt.).

I've made the plunger according the specs listed in this topic and I am using thin walled 1" pvc, but I have no idea if the seal is good enough or not. Should the plunger move with negligible resistance?