US Cartridge, 37mm TP-T, M55A1
These projectiles are similar in ballistic properties to service projectiles and are used for practice firing and training in marksmanship. They may be made from service projectiles or from components similar in shape to service projectiles. This round was designed to simulate the M54 HE shell for practice firing.
The projectile is made up of three parts. The body has no filler, but is made the same size as the HE, M54. A tracer cavity is machined into the base. Since no filler is used, the tracer does not have shell-destroying qualities. The tracer consists of red tracer composition and igniting compound closed into the tracer cavity with a celluloid cup which is sealed with adhesive compound. The fuze, dummy, M50, is entirely inert and is made in one piece of cast aluminum. It is the same size, shape, and weight as the M56 fuze.
Collaborative Ordnance Data Repository