Increasing Max Ammo/clip size through weapon manufacturing

[Shakilrahman96]

So I have a decent powered weapon that had 110 clips per round and 800 ammo , it was the "EZ VorfuB K1" but I foolishly added a (S) ammo round and it completely fucked up the weapon reducing its max ammo to 345... this is a huge blow.
Any weapons that can be farmed from a specific mission that will help me get a weapon that has "Increase clip size/ammo (X/XL)" really fast?

The weapon itself is a decent one but it runs out of ammo far too quickly... it was absolutely perfect at 800+ rounds I could destroy a mk3 abductor in under 2 minutes without having to get ammo...

Any specific spots I can find a weapon that will modify my weapon back to its former glory? this really sucks for the time being.

Whoops, should have added the weapon has a rarity of 6 and is a level 3...