Why not get the HK which can handle 45 Super as it comes from the factory?
The 10mm 1911's seem to earn a reputation for getting beat up by full power loads and the 45 Super exceeds the 10mm so I'd be a little concearned about long term durability of the 1911. Maybe they're made from better steel today than when the 10mm was released and it's not a problem though.
The 4506 is a very strong gun and everybody and their brother doesn't have one. I think I'd build up the 4506 over the 1911, if I didn't get the HK.
