They all seems pretty good and I see you're going for a CC-type build

Because of the base magnetic damage cold is not nessasary for shield killing in the void. Your infested build would be better for the void because fire has better damage bonuses than cold. 

I also want to let you know that by building for status you are losing over 50% of the synoids posible damage.

PureXXX is right. I only have p pestilence in my build and still be 64% proc.

http://warframe-builder.com/Secondary_Weapons/Builder/Brakk/t_30_30002220_193-5-5-195-1-5-200-7-5-204-4-10-206-6-5-209-0-5-212-2-3-263-3-3_209-6-195-11-212-7-263-7-204-7-193-6-206-6-200-9/en/3-0-4/16958/0

Just swag out elemental, and wep in this case

change the +60 proc/damage against the pure damage ones except you are going for an 100% proc build (that in most cases is more for fun purpose).

also i would recommend you to take a primed heated charge if possible instead the normal one and im not sure if seeker is that neccessary, but maybe thats mainly cause i dont like the punch through mechanic^^

@jayxwhite gunslinger is unnessesary since you have a lethal torrent in the build Brakks fire rate is capped with lethal torrent put a magnum force on there or something that adds more dmg

Anemic Agility is ALWAYS better then Gunslinger, even with a slight /hit damage loss both your burst and sustained dps will increase slightly

This is my tower build, it has the maximun burst and sustained dps posible with the Synoid gammacore and has over 50K burst dps (78-50K burst dps depending on enamy type) with ALL FACTIONS. this is my prefered build. having only a normal heated charge will significantly lower damage and make it a less viable all faction build (67-38K dps depending of enamy type)

http://warframe-builder.com/Secondary_Weapons/Builder/Synoid_Gammacor/t_30_34000000_193-7-5-196-1-5-200-3-5-204-5-10-206-6-5-209-0-5-404-4-5-487-2-10_209-6-196-5-487-16-200-9-404-9-204-14-206-11-193-11/en/3-0-55/49251/0

Good luck with this build now

Your whole ammo supply will last you ~12,5s not counting reloading (which will take you another 6)

Yeah, i wrote that before the nerf, i have now moved onto Rakta.