2.5mm=.098 of an inch or 63/640 ( that is a fraction) Direct Conversion Formula 2.5 mm* 1 in 25.4 mm = 0.09842519685 in
14 gauge
12 gauge is thicker than 14 gauge.
2.10mm thk
14 gauge is 0.0641 inches or 1.63mm in diameter.
A little over 1".
Standard 23 gauge wire is (0.0226 inches/0.57404 mm) thick in diameter.
about 0.55 inch
Standard 23 gauge wire is (0.0226 inches/0.57404 mm) thick in diameter.
Assuming this is a firearms question- the 14 gauge shotgun is very rare today. The bore diameter is smaller than a 12 g, larger than a 16g, and runs ABOUT 0.695 inches. That converts to about 17.65mm. If you are seeking to convert wire gauge, or sheet metal gauge to mm, please repost with that information.
10 gauge: 3.57 mm11 gauge: 3.18 mm
0.7 mm = 21 gauge- Google it