I know the USC 45 is a carbine and a carbine to me that uses pistol ammo is more a pistol than a rifle. I have a friend in Germany who went to a HK factory and he was able to watch them make his P30. I told him that I wanted the HK USC in 45acp but the only magazines were 10 rounds. He told me I was wrong and he is sending me 4 30 rd USC 45acp magazines. If they are for real then I'm putting down the 1350.00 for one and when I rebound from that one then I'll get the P30 at a Gun Show. Every gun store owner and store emplyoee tell me that I'm nuts and there is no way to have a 30 round 45acp for the USC. I sure hope I can make the round one day to say I told you so. My friend told me HK makes more than what they have on ther wedsite so I'll have to wait and see. I was going to get another CX which as been a great carbine and fun to shoot steel targets. with but I know deep down the HK has to be better
Carefull, there are rules for the importation of military devices (magazines)
The HK USC that is available for purchase here in the States do indeed only accept 10 round magazines. The magazine well is different and will not accept 30 rounders. (Actually, I though they were 25 rounders for the USC but who's counting). There are some sites out there that sell the materials to do a USC conversion (just google that) that replaces the magazine well, rear block and a few other parts to make it into an original style double stack USC. The last I'd heard, it takes about 2 grand to do the conversion, on top of the cost of the original rifle. The high cap mags are available here in the States as it is, but they will NOT fit in the rifle that is for sale in the US.