I have the legendary gunsmith, who allows you to customise your weapons.
Once I started playing around with it, I realised that developing certain addons for one weapon would make them available to others in the same type - for instance, scopes & suppressors are shared between sniper and assault rifles, and certain ammo / magazines and stocks.
I realised that I was able to research the same addon (for example a foregrip) for two different assault rifles... so I was essentially paying twice for the same thing, since I can just customise rifle B to add rifle A's foregrip. However, not researching the foregrip for rifle B blocked further progress.
Considering that I'd end up researching the same thing more than once, it seems like a waste of GMP to research everything in a weapon type - is there an advantage to this, or would focussing on a single weapon (UN ARC for instance) be a more cost effective strategy?
Are there any addons for that weapon type that I would not be able to acquire if I chose a single weapon to develop?