Probably suggested before, probably going to be berated.

Tool Slot 1 and 2.
May be interchangeable with different tools. The spade and pick slot.

Primary Slot
Fits in your main weapon. Interchangeable with guns and stuffs
Shotgun, Battle Rifle, SMG, ETC.

Ammunition
Mainly for the shotgun, pick your ammo.
Buckshot, Slugs, Tracers, etc.

Secondary Slot
Comes after the primary slot.
This takes care of special weapons and sidearms
Pistol, Panzerfaust/LAW, etc.

Explosives Slot
Nades, Dirt nades, satchel charges etc.

Block Slot
Regular building blocks, cement, barbed wire etc.

Special Slot
Special things, I.E medic pack/ammo satchel/mortar.

Shotgun Ammunition
Honestly, I have 3 different ideas on it.
Buckshot-
Good old buckshot. It's the more "standard" ammunition. It's pretty much a casual shell compared to the others and is good for good old CQC or tunnels.

Slugs-
Slugs. For shotgun sniping and more! It acts like the sniper rifle anti-material round of the shotgun. However, not the best in CQC due to the lack of max damage.

Flechettes-
It would be more lethal than the buckshot, but have it's flaws. Along with horrible block damage, it could have it's problems in other areas. Randomly came to my mind and thought it was good, considering it was in vietnam and the fact I like flechettes ^_^

Body Armor
You start with none, but if you run to the tent or (maybe) kill someone who has it on, you get it! Besides an awesome cosmetic effect (hopefully), it does stuff too!. Any shot in the body will take a damage reduction of 25%, with that damage taking into the armor. Headshots and limbs are unaffected. If there is resupply via running over dead corpse areas, then going to a dead person who had armor on will resupply you a bit (100%-you gain 40%, 50-99% - Gain 30, 30-49%-Gain 20, 1-29%, nothing).

Damn son, imagine if they added hollow points or FMJ...

also support

Hollow points are banned in warfare and FMJ isn't exactly logical considering we have only 1 type of block.

BUT STILL

FMJ one hits blocks/goes through enemies with less damage

Hollow Points do more damage, but does shit to blocks?

/cry

Nevermind then.

Added body armor.