how?: well, lets examine the bayonets use
spear is designed to be a ranged weapon. keeping the enemy out of range of a sword. in the BF2 engine, it doesnt matter what you see from 3rd person, you have to be standing next to the enemy to stab them, thus negating the realisim of the bayonet.... Effectively turning the gun into a spear.
draw time:
its takes aproximatly 3 seconds to draw the bayonet and attach it to the rifle in PR. the bayonet is suposed to be a quick option for when you run out of ammo for your rifle. therefor attaching your bayonet to your rifle when you run out of ammo is unrealistic. in the 3 seconds it take to attach your bayonet, the man charging at you with his knife is already on top of you.
the SKS bayonet was realistic as it was always deployed and took less then a second to switch between the rifle and it.
now i dont know about you, but if a man is charging me with a knife, im not ging to fumble with a bayonet. im going to draw my own knife and fight back.
and of course we cant forget all the extra work that R-DEV Chuc has to do to animate bayonets for every rifle varient.
source: http://en.wikipedia.org/wiki/Bayonet








