Comp Design

[tightloop]

As my Foo Foo gun gets closer to completion, I am starting to try to decide on a comp design.

As I look at most of the guns displayed on this forum and elsewhere, I am having a hard time understanding why there are ports on each side of the comp, forward of the top vents. If the idea is to hold the gun down, why side ports at all.

[BrianH]

Some people seem to feel it cuts down on the side-to-side movement of the dot; most call it "dot occillation" or something like that. I've never really noticed any difference, but some have. Putting in side ports is easy...I'd say do it if you want it.

[tightloop]

Side to side movement when? Before you shoot, as you shoot, just after you shoot? It never is going to be completely quiet...

[PaulW]

Side to side dot movement during recoil is what Brian is reffering to. Most people will try and find the right combination of comp, load, and springs so the dot with track consistantly vertical, without any side to side wiggle (ocsillation) of the dot. It's all pesonal preference on where and how big the side ports are.

And you are correct, the dot will never be completely quiet. But we are always trying to get it that way.

[blkbrd]

Think of it like this.

The side ports counteract the recoil imparted due to the bullet accelerating down the bore, and the top ports are counteracting the pistol moving muzzle up due to the boreline of the pistol being above the center of movement resistance I/E your wrist.

in a "perfect world" you could build a comp that would utilize gas presssure to counteract all recoil forces, but this will never happen due to the physics involved with the gas delay vs recoil action.