This weapon was created because of the concerns with standard incendiary ammo in most guns. Modern incendiary ammo has the problem of exploding in the weapon, especially if it is fire from an auto or semi-automatic weapon. It was only truly effective in small caliber weapons or shotguns. But this limited its effective stopping or killing power.

The SN-21P delivers the right amount of killing power, with the greatest amount of safety. This shotgun style weapon is also a good alternative to the larger, more cumbersome SN-17. Its lighter weight has made it a useful addition to any teams arsenal. Its only limiting factor is that it does not have semi-auto capability, and its lower payload then most weapons. It makes this up with its greater amount of damage, and range of most shotguns.

The weapon can also be broken down in to seven parts very quickly. This allows the weapon to be easily concealed in a breifcase or back-pack. It also makes repairs and alterations faster. This weapon is quickly becoming a standard for all S.N.A.I.L. agents.