The horrors of the Cardassian conflict and Dominion War expressed many deficiencies in Starfleet capability, especially in infantry ordinance. At the time, the poorly distributed Isomagnetic Disintegrator was the only step above the Type-III phaser rifle available. That changed with the introduction of the RPPG launcher.
The weapon fires small, globe-like ammunition from a square magazine of six. The projectiles are a mix of present day's toned-down photon grenades and the small micro torpedo. Each projectile has a tiny rocket engine for minimal weight (and purposely short range), with a variable yield warhead perfect for everything from anti-infantry to anti-vehicle warfare.
The launcher itself is a small, silver tube with an ample shoulder brace, not unlike a lengthened and padded isomagnetic disintegrator launcher. The launcher first uses a chemical explosive to initially propel the round (a larger scale version of the process used on the TR-116), and the round's rocket summarily boosts it to speeds exceeding that of sound.
However, the launcher's limited application in peacetime means it has yet to be widely deployed, and it is mostly stocked on space stations and large/combat oriented starships.