MBA Gyroget Mark II
A rather odd, obscure pistol, the one in the photo is chambered in 12mm. An interesting design but complicated, expensive and extremely inaccurate; one test group at 33 yards produced a 29” inch grouping. In spite the fact there are considered commercial failures, they are collectable and can fetch $2,000~ depending on condition and if they have the box and manual. (GRH)
Regarding the last image.
This time lapse image shows the rocket blast of the Gyrojet projectile being exhausted from both sides of the rear of the gun. The small separated red discs in front of the muzzle indicate the projectile is just starting to rapidly rotate, which transitions into the spiraling circles starting about a foot from the muzzle, indicating a high spin rate. The angled exhaust nozzles allowed a very high spin rate of five revolutions per foot, or 288,000 rpm at 960 fps.