Your modern Flak armours are akin to ( but not quite the same as ) Shank armour/stab vests used by SORT..this i KNOW as fact having worn and worked with both ( prior Army and corrections SORT team member )..However the Flak armour would be of use against a bow given its design is to lessen/prevent the soldier from getting shreded by shrapnel from explosions ( NOT bullets ) So i would actually say that the Flak armour does count as normal ( Not primative ) against bows ( i thought of the flak armour afte the initial posting and how it could work vs bows ) but as for all your mesh and bodyglove type armours..they really offer little to no protection against a good bow ( or anything with a blade for that matter )  Simply put some weapons are better at defeating certain armours than others are...what might be good against one type might be crap against another and vice versa...ultimately its up to the GM to decide.

ALL your SP class weapons are nothing different than we have currently. We dont have Las weapons at this point ( at least not for battlefield use of soldiers ) and Plasma weaponry...lol thats gonna take some time...BUT..as far as the armours and ANY Plasma weapon hit..SORRY Charlie but your TOAST if your wearing anything less than carapace armour...I dont give a S**t what the book says...simply put...They didnt think bout it all..My group ( as ive sated in older posts ) are all prior soldiers and technicians...they enjoy coming up with what most consider off the wall things using real principles ( giving me a headache or a good laugh one or the other usually ) in order to solve the challenges i toss at them

Long and short of it would be that Plasma weaponry by its very definition will annihilate ANY soft/cloth based armour you toss at it in one shot due to the simple fact of the physics involved in creating plasma ( This is NOT simply a hot round of gas....its burning highly energized matter at several thousand degrees!...sorry but even IF you wore armour that took the hit..your still screwed from the ambient heat wash sufficient to (1) knock you on your arse and (2) sufficient to cook off ANY solid state ammo you have in addition to charring your body and melting most substances down onto your body causing excruciating pain ( and secondary damage )

Lesson for it...Only use the rules listed in the books as general guidelines and streamline your sessions as GM however you want to make it fun for everyone as well as easy ( Rule of Cool )...In my groups case..thats taking a more reality twist to things...afterall the game is supposed to be about more than hack and slash...its supposed to promote thinking...lol and trying to figure out how to get around heavy weapons like that and owning the enemywithout getting trounced in the process is something my group ( to date ) has accelled at using "reality based" rules ( with some added technowizardry thrown in for added fun )