Wow man. Incredibly faithful recreation of such a long-standing and beloved pistol.
I only recently became familiar with the HK USP, but I know many other HK weapons and pistols and this is really great detailed.
Also impressive is your CAD wire-frame designs with sectional highlights.
I'm sure you're familiar with the 3D-Printed models like the FGC-9 by JStark, may he rest in peace. He was a true rebel, and a talented guy.

My favorite handgun by far is any original pre-WWII 1911 that's also chambered in .45-ACP. I hope to get one as soon as I get my pistol license. I held two of them a few months ago that were made in 1926 & 1918, and they were beautiful.

Much love.