Sniper rifles have longer barrels that both suppress barrel flash and increase muzzle velocity - thus making the rifle more accurate at longer distances. They a

Sniper rifles have longer barrels that both suppress barrel flash and increase muzzle velocity - thus making the rifle more accurate at longer distances. They also fire larger rounds with larger cartridges to get even greater muzzle velocity. The trade-off is size and weight. Longer barrels, larger rounds, bigger cartridges - that increases the size and weight of the weapon and its ammunition. That's size and weight an infantry neither needs nor wants.