The body is made out of machined 6061 aluminum with the same aluminum for the barrel and loading tube. The loading system will be a lever actuated (old school Winchester style) falling block breach. The lever forces the block up, allowing the spring fed loading tube to slide a cartridge into the block. Then the lever is pulled back into place causing the block to return to the firing position so the firing pin can be hit, launching the canister.
Here is the finished product!