I finally bought one....
Three weeks ago. Original stock (which was what I wanted), vent rib, etc. I won't be shooting it until probably spring though. Got to get brass and dies!
I haven't seen any factory ammo locally for years, but it is still listed online, and I expect I'll be getting some, Eventually.
I passed opn a number of them over the years, all with custom stocks and usually in some even more exotic caliber, because I wanted one in original condition, to complement my collection of model 600 rifles.
Didn't get the case or anything else, just the gun, but it looks like new, so I'm not unhappy. Great trigger pull too!
I can't recall just what they sold for when they came out, but I do remember that $99.95 was the MSRP of the model 600 rifle when it hit the market, and what my Dad paid for the .308 that I have today.
For a long time I could never figure out why Remington came out the the .221 Fireball. I mean, why didn't they just chamber the XP-100 in .222 Rem? It finally dawned on me a while back. The smaller .221 case holds all the powder you can use from the 10" barrel. Its more efficient. And, it gives Remington one more thing for us to spend our money on!