Smaller selection of bullets sort of depends how badly out of spec the 45 turns out to be. Numerous people have complained their lands are running .453 or larger on the new CVA 45cals. That sure makes choosing a land rider difficult. Most 45cal bullets wont be lager than .452 with only a handful of exceptions. Those over size bores also make using sabots more challenging. The Harvester sabot is only about .454 load OD with a .400 bullet.
Now days there are several 40s you could make work in a CVA 40cal with an adjustable sizing die. The only thing i really dont like is the 40cal is a 1-20 which is a bit slow of a twist for bullets over 250gr. Other vendors and customs are 1-16 or faster. Those will shoot a 300gr no problem.