as said, i need to get some usp 45 compact mags quick.  i was under the impression that the usc mags are the same?  is this right?  I'll be picking up my new usc next week as well, so that'd be great little feature of them both.

No, I don't think that they're interchangable.  USP mags are double stack single feed.  USC mags are single stack, single feed.


ETA...Here's what USC mags look like.  They are not cheap.  I listed these on gb about a month ago.  I didn't know what they were worth.  I started the auction at $60 but the final price was something like $150+S&H.

yea that makes sense.  maybe it was the hk45c

No, I don't think they'll work either.  I don't know of any other mag that is compatable with a factory stock USC.

The only mags that fit the USC are USC mags and the only mags that fit the USP are USP mags (Mark 23 mags will also fit the USP .45 but the older short lipped USP .45 mags will not work reliably in the Mark 23).
The USPC 9mm and .40 mags are the same as the P2K mags and will fit the SK also, but the SK mags will not fit the P2K and USPC (too short), and the USPC .45 and the HK45C mags are the same in both 8 and 10 round versions.  The HK45 mags fit the HK45C and USPC .45
The P30 mags fit the USPC and the P2K/SK.