I've tried several and was not satisfied with anything until I got the Galazan upright 12-16-20-28 riser type multi-gauge. If I could get accurate readings at all with the others (operator error for sure), it would take 20 minutes of measuring over and over again making sure I didn't get a false reading.
On the Galazan gauge its 100% right and it measures quickly.
Personal opinion sidebar: I feel that unscrupulous dealers often use other types of gauges because they give a "generous" slop reading. I know a guy that bought a .021" gun that measured .017" on my galazan gauge. My gauge was right and it picked up subtle nuances from non-concentric boring. The value difference on the gun because of that difference in minimum wall thickness? I argue at minimum, 25%.
The Galazan gauge (or the Purdey version, etc.) will pay for itself if you intend to own more than 3-4 best guns.
