Unsafe 20 gauge VHE barrels

[Bruce Day]

I think you need to find out the real and exact measurements .

[edgarspencer]

I learned, a very long time ago, several rules when shooting: Foremost amongst them are, 1) Know Your Gun; 2) Know your ammunition; 3) Know your Target.

Your situation falls under #1. Where, along the length of the barrel, does it measure 'under .020"? If this less than 7-8" from the muzzle, then apply #2.
A light load such as the RST Lite is a delightful load and I wouldn't fear shooting it if the pitting is far enough (distance and pressure) down the tube.