A colleague sold me an unfired USP Expert .45, Variant 1 with four 12-rd mags for less than half of the original retail cost. I see light handling wear so I assume it was an unfired demo gun that HK reps took to shows or government demonstrations. The gun still had a heavy duty tie-wrap on it when I bought it. Since I'm a sucker for a good .45 ACP shooter and I've never owned an HK, I bit. But HK is new to me. (I use SIG professionally and SIG, SA, & S&W privately.) I've only dry-fired this HK and field-stripped it. I noticed a couple of things I don't see on my other auto-loaders. There is an O ring on the barrel that HK claims it improves accuracy. Also, there is an ambi control that is a safety and de-cocker, a very interesting feature. One control can allow Condition 1 and de-cocking. I know I'll need to replace the O ring and recoil spring. Who specializes in HK parts besides Brownells? What holsters fit the Expert? The trigger is not as smooth as my SIGs. What pistolsmith specializes in HK handguns? What should I have done besides a trigger action job? Sorry for the battery of questions, but the more I stare at this handgun the more I wonder about it.