Dewey Vicknair has demonstrated just how little lateral pressure it takes to deflect the long round bars on this type of wall thickness gauge, causing inaccurate and inconsistent readings. Naturally, they cannot tell you anything about wall thickness under and between the barrel ribs. And the ball cannot reach down to the bottom of pitting to determine just how deep they really are. This subject has been discussed here numerous times in the past.
They are better than nothing in the hands of a skilled operator. Someone will be along shortly to say Dewey is wrong, but your experience proves otherwise.
