the u.s. army uses the fn M249 S.A.W.(squad automatic weapon). it replaced the M60.
the five seven shoots the 5.7x28mm at about 2100 feet per second.
its the same round that the fnh carbine rifles shoots. so, makes sense for tactical teams to have a 20 round hand gun that uses the same ammo as their rifle. rumor is that this round is effective against some styles of body armor. because of that consider the possibility of a democratic president banning these pistols for civilian use.
i have handled a five seven it was $850. it felt strange to me. almost like a toy, there is alot of ploymer. even the take down lever and mag release were poly.
dont mistake that for poor quality. i dont own a fnh but i have researched and the fnp-9 and fnp-40 have their fan base.