[edgarspencer]

Call it a Clymer, Manson, or Brownell, the gauge is the same. Two things are certain: It's a perfectly reliable tool in the hands of someone who knows how to use it, and, There are a lot of people who don't use it correctly.
I like John Hosford new gauge better than the original version. The 'beam' is either an aluminum investment casting, or CNC machined. The old one(original version, with 1" aluminum tube) is just as good.
When I hear people complain about the perceived lack of rigidity of the rods on a Manson gauge, I am almost certain their technique is lacking.

The barrel must be Horizontal! Whether you're fixing the lugs in a soft jaw vice, or someone is holding them on a table edge makes little difference (unless the table is on a thick rug, the backyard, the beach, or some other soft footing.
Hosford's barrel support rod is the best part of his gauge kit (he will sell them separately) as it allows you to easily rotate the barrel to get readings all around.
Hosford's YouTube video on Zeroing, and using his gauge is very good, and the points he makes are equally true if you're using a Manson (Brownell, Clymer, etc) gauge.
The diameter of the rod inserted into the barrel is the same with all gauges, and has to be small enough to get freely into the bore. My Manson gauge came with a 1/2" rod, and 9/16" ball, so it was too big to measure 28 gauge guns. I simply made a new rod, 7/16", with 1/2" ball.
The eyebolt I added to my gauge, like the ring on the Hosford, makes holding both easy, and repeatable.
The other (lower) rod simply holds the dial indicator, and since the dial is on the bottom side, gravity means it flexes to it's same amount each time.
As long as you're paying attention, and don't allow the upper rod (Same true with Hosford) touch the barrel, you'll get steady, and repeatable readings every time.
Initially, I thought Tony's vertical measuring fixture was the cats meow, but quickly realized it's actually easier to influence the rod deflection, and even fussier to get true, and repeatable results.
I've watch lots of people struggling with zeroing the dial on their indicator. Best way (Take it from someone who has a terrible hand tremor) is to hold the gauge between the ring and EXACTLY AT THE BALL, visually observe it's either at zero, or note the reading, Then hold your thumb on the end of the indicator rod, which prevents the dial from deflection, and rotate to zero.
Because of my tremor, When checking ZERO, I suspend the unit between two points, one at the ball, one at the ring.

Note to that Nit Picking fuss budget (Yeah, You know who you are) who spends more time looking at stuff in the background of my pictures, Bite Me! The Maid is on vacation.