The barrels are exactly the same inside & out, and both are carbon steel, so far as I can tell. Barrel length is 3.75", or thereabouts, on both. The HE gun is Variant 10, while the SS gun is Variant 2, but that shouldn't matter. I've done what I can for the SS gun by replacing the factory sights (which shot low with anything & everything, even with 230 gr +P) with Ashley Express sights; a higher-than-usual rear sight now brings POI up to POA, approximately, but consistency is still poor, with best groups at 3-4" at 8 yards (piss-poor), while the HE gun has POI=POA exactly, with "one hole" groups. The guns appear to be equally tight in barrel-to-frame fit (slightly sloppy, kind of like Glocks, just a little tighter) and in frame to slide fit, and single action trigger let-off feels just the same on both. Too bad there's no "lemon insurance" for guns! I suppose I could send the gun back to H&K, but I'm not sure if "unacceptable precision" would be considered a defect by them, or not.
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"Potius sero quam nunquam."