These are two great handguns manufactured by the premier company Heckler & Koch. In 1995, they developed the HK USP Compact, the with a few modifications they brought the 45C to market in 2007.
HK45 Heckler & Koch
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an actual gun thread in GD!!! HK USP .45 range report
Heckler & Koch USP 45 vs Heckler & Koch HK45 size comparison
Heckler & Koch USP 45 vs Heckler & Koch HK45 size comparison
From the Safe: HK 45 Compact
Hk USP compact 45 vs Hk45c
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The Heckler & Koch USP and the Evolution of the H&K .45 Auto Caliber Handguns – Small Arms Defense Journal
A Battle of HK .45s: HK USP Compact vs HK 45C
A Battle of HK .45s: HK USP Compact vs HK 45C
The Heckler & Koch USP and the Evolution of the H&K .45 Auto Caliber Handguns – Small Arms Defense Journal