I cant get too excited about using a flint gun or percussion if cartridges are around. By around, I mean cases. They work fine with black and cast bullets if need be, and as was brought up, primers are the weak link. Enough primers can be had to last a lifetime though for fairly reasonable amount of money, (at least before the latest panic). If I'm stockpiling anything, it would be primers and smokeless powder. One pound of smokeless will load about 1000 rds of 44 spl or mag, or slightly less than 1000 45 Colts. Both work as pistol rounds and carbine rounds. The same pistol powder can be used in 30-30 and 35-55 for black level loads and be far more economical to make rounds with than black and caps. Sorry if that sounds sacriligeous, but it seems much more practical to me.
Primers, powder and bullets could also be salvaged from cartridges that dont chamber in your guns. Anyone with a bit of reloading experince, a good manual, bullet mould, and some time could make loads from one caliber to another.
As far as wheel weights, be sure you aren't getting zinc weights, they are becoming far more common the past couple years, and the word is will be standard for wheel weights before too long, the lead ones are being phased out.