John, all you have to do is examine the internals of all the poly pistols. Most of them typically have small rails just over the trigger and at the rear of the frame. Ruger, like the XDm uses a removable steel chamber-block mid frame that incorporates longer rails than are typical in most poly pistols. Then there are polymer rails at the front of the frame that engage the front of the slide. You have the stainless steel chamber-block where the chamber is surrounded by steel with the longer rails it provides and rails at the rear that give 3 engagement points between the slide and frame rather than the typical 2 while at the same time the Rugers are the slimmest double-stacks period. A 17 round SR9 is thinner than a 1911.
As far as H&K, I bought a USP as soon as one became available in 1994. It's trigger was rather unimpressive and since it's weight advantage is minimal compared to an alloy frame SIG/Sauer, I think that's the better comparison where the S/S pretty much sets the standard for DA/SA autoloaders. I have not fired an FN FNP USG and now they've been replaced by the FNX version with a shorter barrel. I thought about buying the FNP USG which I could have done for around $600 compared to the HK45 costing over $900. I do handload and have for over 28 years so I don't want any pistol with a polygonal bore, period. And I won't buy a pistol because of an inflated rep. The H&Ks are very overpriced. On top of that, I like the safety system on my SR9 and SR45.
Kahr's are not really in the same category (service size) but I have shot them. I'll take Ruger's trigger system over any DAO any day of the week and there are too many reasons why I wouldn't own a Kahr anyway, especially compared to the S&W Shield or XDs.
