I asked this question on this forum a few months ago (I got a USP40C for Christmas) and was referred to Berry's Mfg:
http://www.berrysmfg.com/
I have loaded about 1000 of their 135 grain round shoulder plated .40 bullets and have been nothing but satisfied with the results. I have also loaded about 250 of their .357 plated bullets (125 gr H.P.) and have been happy with those as well. They said that their plating is good for 1200 to 1300 fps but I have ramped them on up past 1500 fps (125 grain on a max load of 2400) with no noticeable issues (they said that the plating might not hold on ... causing flyers) I have shot them quite close to a target and looked for small holes due to plating fragments and found none and have never had a round land more than 4 inches off the X ... I'm sure that I'm to blame at 25 yds shooting freehand. Your milage may vary, etc ... but mine has been great! Oh ... the prices on their web page include shipping!
saands