Last year after taking the sierra blaster test I went to sleep and woke up with a better mouse trap idea, a mekanical blaster, no hoses or wires. with my son having a scrap yard and a full fab shop all I had to do was gather materials an place them together and have him weld them all together. simple design with a free floating firing p.in and 410 cases loaded to 375 Winchester. at first I had just weights on the top but you could not shoot sideways so I added springs so now it will even shoot upside down. Tom

There is already a few out there, the boulder buster is the same concept in that it has a breach, firing pin and a barrel and shoots a 12 gauge round but you have to drill a big hole and it is exspenseive  The micro blaster has a firing pin and uses air to discharge and the sierra blaster uses elect. to fire.  The boulder buster would probably be considered a firearm in calif. Tom