Whenever I got bad weapon drops in SupplyRaid, I would pick up and use the enemies' sosigguns. It sometimes felt like cheating, especially if they had decent sights and higher power than I was supposed to have, so I decided to make a SupplyRaid character where using sosigguns isn't cheating.
Sosiggun Soren is a character for the SupplyRaid game mode, balanced for use with SafehouseProgression. Soren's playstyle is built around being low on ammo for your regular guns; you'll need to conserve ammo by grabbing and using sosigguns where possible. If you're lucky, a sosig might drop the real version of a sosiggun for you to bring home -- there are 57 guns, 6 melee weapons, and 4 super-rare guns to collect.
Soren's difficulty depends heavily on the characteristics of the enemy faction you're playing against, namely: The armour and weaponry of the sosigs; their respawn rate; and the number that can be on the field at the same time. Soren comes with a custom faction, the Slow Burners, that gives a gentler difficulty curve and longer respawn times so that you have more time to scrounge for sosigguns.
I suggest setting Spawnlock Enabled for Soren, but not spawnlocking ammo. There are two reasons for this:
A grappling hook, range finder, and flashlight are free at supply points if you need them for the map you're in.
Stun grenades and smoke grenades are free at every supply point. Use stuns to disable approaching sosigs. Use smokes to obstruct bad sightlines, especially when you're outranged.
Some ammo boxes are sold in the Melee section of the shop, for use with guns that need to be loaded with individual cartridges (shotguns, revolvers, bolt-actions).
Looted weapons come with the bare minimum, e.g. a shotgun drops with a box of 5 shells. Weapons that you purchase from the Buy Panel come with significantly more ammo, and sometimes other attachments.
If you put lots of empty magazines and speedloaders on the Ammo Refill table (even ammo boxes!) you can refill everything with a single purchase.