Very cool piece that no military gun collection is complete without. Mr. Richardson's gun design may have not been a commercial success, but the man's amazing experiences and vibrant life story make this an interesting collectible. There shotguns were also made in 10 Gauge. The idea of slam fired single shot guns have been around in the Philippines a very long time and are not a new concept at all. The gun was originally marketed to the military after WW2, but was dismal failure commercially.