Well I can understand that conversions like my voodoo gun can and do scare professional gunsmiths. I understand the risk involved with it and as such assume my own risk. While I do not claim to be anything near a gunsmith I did research into it a fair amount before diving in. I have spoken to a gunsmith in Alaska that has done this for his own carry piece as well as for half a dozen or so others. He proof tested it with 200 grainers at 1400fps and settled on a carry load of 1300 fps with the 200s. He has to date fired over 5,000 rounds through it without failure. Does this mean it's okay? Maybe not, but 10mm is to me what 9x23 is to many on this board.
My thought process here is simple, which could be my problem :smile: The USP40 was designed as a .40S&W gun, unlike many others that were 9mm built over as a .40S&W. This fact alone means to me that it is stronger than other .40 S&W platforms. As far as the, "10mm is higher pressure than .45 and the fact that the USP45 is a larger platform." I don't know that that matters as much as people may think (this is a common argument for those that think the 10mm USP is a bad idea). After all, the 9x23 is higher pressure than the .45ACP but 1911s are converted all of the time. In addition, the USP357C is a smaller yet version of the USP and it is chambered for the .357 Sig which operates at 40,000psi max pressure.
We have the USP40 which handles the .40 S&W cartridge at max 35,000psi. The USP357C which handles the .357 Sig at a max of 40,000psi in a smaller package. And the USP45F & USP45C which are larger than their .40 S&W and .357 Sig counterparts handling the lower pressure .45 ACP at max 21,000psi. The 10mm with a max operating pressure between the .40 & .357 at 37,500psi. My logic is that the USP45F & C are larger because the .45ACP cartridge is larger.
Now although the 10mm is lower pressure than the 357 Sig, recoil for me is greater with the 10mm duw to heavier bullets. A 200g JHP @ 1200 recoils more than a 125g JHP @ 1400 in my hands. I don't know if there is a mathematical equation to show the relationship of fpe to recoil but I would assume that 10mm would be harder on a gun than 357Sig despite it's lower pressure. I could be wrong and please correct me if I am.
On a slightly less correlated note: Glock has the G20 and G29, both in 10mm. The G29 is smaller than the USP40F yet can still handle the more potent 10mm. I also think that polymer framed guns will be more forgiving than a steel or aluminum frame.
All in all I guess I'm saying I don't think pressure matters as much as energy. Which in this case means I'm saying that based on pressure as I understand it, it is not the sole reason for a gun design or it's ability to handle a cartridge. On the other hand, I am saying that 10mm develops more energy or recoil energy which in my interpretation means more stress to the gun. So in short, I don't think this is a bad idea based on pressure alone, but it may be a bad idea regardless of pressure. Factor in the anecdotal evidence from the gunsmith in Alaska that has not had any problems, my love for the 10mm, and my (maybe poor) judgement and I chose and do choose to do it regardless.
I specifically asked you for your input Dane, and I am very appreciative for it. As I said I am not a gunsmith and do not even play one on TV, so if any of my assumptions or information is wrong, or you find fault with it, I would be more than willing to hear it. I have been surfing assorted gun boards for a few years now and of all the posters I find you to be among the top of the list when it comes to sound knowledge and advice. I would commision you to build me a 9x23 1911 but I have instead commisioned my wife to have our fourth child, so unfortunately for me it's not in the finances for some time. Of course another child is a whole 'nother kind of joy.
I guess I just want to say that my argument is based on my logic which may not be right, and I would be more than willing to hear your thoughts and/or rebuttal of my information. Have you ever run into the collar issue on your Kimber conversions? Or do you just avoid it by replacing the barrel with a new 10mm one? Thanks again for your input.