OK, I did do some math. It may be off a few thousands because I used a basic caliper and mechanics rule - not a slide caliper. I may do that tomorrow.

I figured that the wall thicknesses are as follows:

H&R Ultra 12 gauge (assuming .729" bore), o.d. 1-1/16": .16675"
H&R Ultra 20 gauge (assuming .615" bore), o.d. 15/16": .16125"
"Regular" 12 gauge smooth bore (assuming .729" bore), o.d. 27/32": .05737"
(JC Higgins Model 20 pump)

So basically yes, the H&R Ultra barrel is 3X thicker than a standard shotgun barrel, atleast in the 12 gauge data.

Just for kicks to try and say yes or no to the notion of the H&R 12 being bored in a 10 gauge barrel blank. If the 10 gauge barrel is 1.0625" and 10 gauge bore is .775" then 1.0625" o.d. - .775" bore = .2875". Dividing the .2875" by 2 for both walls of the barrel is .2875" / 2 = .14375" wall thickness, which would again make the 10 gauge barrel appear bullish beings as that .14375" is not too far off the Ultra 12's .16675 (-.023").

I don't recall the 10 gauge H&R's to be bull looking at all, so maybe the 12 Ultra is made from something more than just a 10 gauge barrel blank. It could be that it is just a generality used to descibe them that the average layman would be likely to understand. Maybe there is a totally seperate blank for the Ultras.