The special "HE" (Hostile Environment) finish employed on major metal parts of the HK USP resists even the worst types of corrosion and wear, including prolonged exposure to salt water.
Heckler and Koch USP Introduction
In a SHTF world, don't leave home without it! ;)
BTW, those look like handloads. I reload and have never had a failure to feed in the H&K USP.