That pretty much sums up the accuracy issue.

Shooting the same weight bullets, the .45 won't have much of a velocity advantage over the .50, but it will have the advantage in bullet BC and SD. A properly loaded .45 won't give anything up to the .50 in overall performance and will exceed it in some cases. Now, walking into your local walmart or gunshop, you will typically find a better selection of bullets for the .50 but, if you're willing to order online, finding a variety of bullets is not a problem.