there ain't really much math to do. The desert eagle deals 2d8 damage size medium. the HK G3 deals 2d10. no such damage figures exist for medium weapons in fantasy DnD, therefore i have trouble converting the damage to size large.
My suggestion for the desert eagle: use a weapon that deals 2d8 damage in size large(bastard sword) as the base, and scale it from large to huge, instead of from medium to large.
The HKG3 is trickier, as no weapon in fantasy dnd deals 2d10 damage. my suggestion: take a weapon that deals 1d10 damage, scale it to size large, and double that.
reasonable?
also, yeah, what sorta consumables are available? healing potions seems obvious(but fast healing is a bitch), but what else? scrolls? oils? hand-sized nuclear charges?
So basically, your Desert Eagle would deal 3d6 damage, and your HKG3 would deal 4d6? Sounds fine by me.
The consumables available are all in hypodermic syringe form, to facilitate use (as well as a way to make one-shot wands, but without the hassle of people having to figure out how to use them).
They all provide spell benefits, as per the list:
All spells of the Cure X Wounds line (treat the added healing as being the maximum, i.e. 1d8+5 for CLW, etc.)
All 2nd-level stat enhancing spells (Bull's Strength, Bear's Endurance, etc.; treat duration as being minimum CL BUT lasting hours/level. The drawback is that you need to roll 1d4+1 for it)
Dispel Magic (Reserves of Strength'd to CL 20; keep in mind they're still considered 3rd-level spells for the purpose of things like Orb of Invulnerability)
All the Remove X condition spells
Heal (limit one per member)
Revivify (limit one per member; does not count against maximum capacity)
In order to determine how many you can take, each one of you gets 13 CP (capacity points). You can take up to twice that in consumable "spell levels" in any combination (so one of you could take 12 potions of Bull's Strength and two CLW, for example, or any combination totalling 26). Alternatively, you may request the use of an item or temporary enhancement equal to half that, rounded down (so you could ask for, say, temporary Boots of Jumping, or adding a +1 enhancement to a weapon).
CP is calculated by adding ten to half your level, rounded down. You will be using this every time you're on a Guild mission so keep it in mind. You may also request specific consumables outside that list at 1.5 times its price (so you could ask for, say, Death Ward, but it'd cost you 4 CP rather than 3). Naturally, when determining spell levels, use the lowest.