[pizzainthemorning]

Didn't mean to sound so secretive.

Essentially the idea is to make a gas blow back airsoft rifle using a drop in mechbox and modified mags. The mags will either be custom made, or possibly from a pre-existing brand. The mag well of most guns would have to be modified by drilling a small hole to allow the hammer to strike the valve. In addition, cocking handles would have to be functional. A normal mechbox will be gutted leaving only the trigger, trigger spring, nozzle, cylinder, and piston. The main power spring in the mechbox will be replaced with a light return spring. This will serve to return the modified piston/piston head to the resting position. The piston head will be modified such that it attaches to the nozzle (this is subject to change). At rest the nozzle will be fully forward, bb in the hop-up unit. When readied the nozzle will be fully back with a bb in the chamber. The piston will also be modified to accommodate the hammer/firing pin (Whatever term is more accurate). The hammer will be a simple linear drive with an in line hammer spring, interacting with the trigger directly via simple sear. Action will be as follows.

From a readied and cocked position the trigger is depressed disengaging the sear with the hammer. The hammer spring forces the hammer to strike the magazine valve in turn letting gas through the vent. The gas travels through the vent and splits in two directions, towards the bb/barrel, and towards the piston. Gas propels the bb down the barrel while at the same time fills the cylinder, moving the piston back and compressing the weak recoil spring. When the piston moves all the way to the rear due to the expanding gas it comes into contact with the hammer arm, a small protrusion from the hammer, and forces it backwards. This motion compresses the hammer spring, re-engaging the sear, and readying the hammer for another shot. The piston, now finished being pushed by the venting gas, is now pushed forward by the return spring, moving the nozzle with it to chamber another round.


There's more to it and I'm thinking out problems/modifying the design as I go, but here's a ghetto picture. Blue represents gaseous movement, and green represents kinetic movement. Something like that anyway.

Alex