The only 1:16 twist barrel i could find - Backup Tactical Sig Sauer P320 Full-Size 9 mm Threaded Barrel

So far so good. 300 rounds through it.

I bought this barrel because I shoot lightweight rounds with high velocity. This barrel is super accurate and consistent with those loads. 90grn - 115 grn. 1500 fps - 1200 fps. It's one of the only 1:16 twist barrels I have found. The bullets i've tried are the Lehigh defense Xtreme defender (Underwood 90gr +p), Hornady Critical Duty, ARX polymer, and the 115 gran Federal and Winchester. All seemed accuracy as good or better than the OEM barrel. It fit right in my P320 X Full.

The only downsides are the crown at the edge of the barrel, it could be finished better, the barrel coating is average the smiley face appears like a Glock barrel. For the price, though, I can't complain the metal and quality used are up to par with 200+ dollar barrels.

My P320 build: X-full slide, 15# 1911 spring and guide rod, Apex tactical trigger, Polymer 80 Ptex320 lower.