What is the fine-grained topic of the following text: It's in .22-LR, and it is a submachinegun; the drum holds 200 rounds, and it fires at a blisterling rate of fire of 1200 RPM, which however results practical when you fire a so small caliber, furthermore it's almost the only way to make it be effective in modern combat situations. Only return the topic.
.22-LR submachinegun specifications and usage in modern combat