This mod tweaks Gun Runner HQ to carry a lot more pistol powder and rifle powder, and to carry a bit more repair materials. It also makes gunpowder available at stores other than Gun Runner HQ (from Chet, Alexander, Blake, and Quartermaster Bardon).

Additionally several stores now carry increased quantities of the materials necessary for the construction of weapon repair kits, and may occasionally carry preassembled weapon repair kits (both especially true in the case of Quartermaster Bardon). Many stores also have increased inventories of other items, but most (but not all; some have slightly increased stocks of weapons or armor, some carry additional caps, and some carry additional magazines) of this increase in is the relatively unnotable "Misc." category of items.

EDIT:
For reasons which I have been unable to pin down, some of the ancillary additions to vendors' inventories may not appear (especially magazines).
ALSO, purchasing more than one at a time of some types of case boxes or hull boxes seems to sometimes crash the game, but as far as I can tell this is an issue with how the case/hull boxes themselves are coded and not with the mod itself.