Within the last 6-8 months I purchased ~1000 rounds of Blazer brass .45 loaded cartridges. All were large primer. Perhaps old stock. But the large primer stuff is still available. Cases reload and shoot fine.
Not buying too much .45 now as I reload, but haven't yet seen small primer .45. Over the last 8-10 months I have purchased Federal, Remington, Blazer, S&B, and Perfecta .45 loaded rounds. All have had large primers.
Forgot, also a few hundred WWB .45, large primer.