Modern variants can switch between different types of ammo, have large ammo capacities to support sustained automatic fire and are gyrostabilized to control recoil. Simpler variants are cheap and difficult to pick up on scanners since they have no energy signature. Some projectile based weapons are also capable of functioning in an area effected by an EMP blast because they lack electronic components.
A completely different kind of projectile based weapons are railguns. They are a little less common in handheld applications, because handheld models usually lack the caliber to be able to fire grenades containing a plasma charge. This plasma charge is an important part of the firepower of larger starship railguns. However, they posses good accuracy and range and are thus used for sniper applications. Low-powered electromagnetic accelerators are also used to chuck large caliber grenades. One advantage of railguns is their penetration - allowing them to pierce astounding amounts of armor.
Railguns appear to be a common infantry weapon for the Caldari, enough that even civilian personnel have no problem using them when necessary