player addbackpack "B_FieldPack_blk";
player addmagazine "30Rnd_9x21_Mag";
player addweapon "hgun_Rook40_snds_F";
Remove suppressor then move pistol to backpack and attempt to then add it back your your handgun slot.
As soon as you do this the pistol will stay in the backpack but will now have a suppressor again.
Now move the pistol from the backpack to the ground and back to your handgun slot and loaded ammo will be gone.