I may be wrong, but I'm fairly certain that the HK45 was originally developed for JCP competition that ended up not taking place. The HK45c came later.In other words, the HK45 is a counterexample to the frequent assertion that HK doesn't do anything to introduce or change a product unless there is a significant buyer. The HK45(c) programs were done for a prospective US military shootoff that didn't happen at the end of the day.
Oh, well, HK45 fs owners seem to like theirs a lot.
Here's a link to the Gun Digest article about the Rangers and the HK 45C:US Ranger's got to play with it during their "top ranger" thing they do. (or whatever it is called) They loved it, but I don't think anyone but the SEALS, and maybe DELTA or GB's get them. But for sure the only people that have them are the SEALS with their MK24 setup.