There's one for sale right now on GB, not mine
The only advantage over 250 would be their 1:10 twist, which handles 115g pills. I think if I were building a 99 quarter-bore wildcat, it would be a fast twist 250AI.
I've been sitting on the brass and dies for a 250AI for years now, thinking about one in a 99. I once had a Ruger tang safety bolt gun in one.
