How many people go looking for a gun, simply because you picked up a good deal in a new caliber and you don't want "single gun calibers"?
I have never wanted a .338 Win Mag, but scored a screaming deal on a No. 1 in that caliber. Now I'm looking at some of the M77 offerings to go with it.
I always keep my eyes open for a bolt gun in .224 Valkyrie, and eventually I am sure I will add another 300 PRC, 6.5 PRC, and 7mm PRC to the stable. The 8mm Mauser and .25 ACP will probably never have two guns, but those ones don't bother me as much.