Ya the 20 gauge still puts a smack on those deer with less recoil. If the gun shop doesnt have it than just order it. It generaly doesnt take that long for a gun to come in.

The outside diameter of the barrels are the same.Only the bore size is different.This results in a little more weight for the 20 which helps soak up recoil and a stiffer barrel which helps accuracy.

I thought that the 12 Ga barrel was made from a 10 Ga size blank, and the 20 Ga barrel was made from a 12 Ga blank. I read somewhere that all the H&R barrels are pretty thick to add stiffness and improve accuracy.

I prefer the 12 gauge, little more velocity and a tad less drop using a Hornady SST.

The "same" as in 1-1/8" v 15/16"?

Yes the thickness is to improve accuracy. It is a little more detailed than that but that is the desired effect.

When I first got my H&R Ultra Deluxe 20ga. I was at the range sighting it in and I was so damn surprised on how much this gun was a tack driver, next to me was a guy with one of those custom Tar-Hunt bolt action jobbers, he was shooting very good as well, but my groups where tighter, he wasn't pissed off at his groups, but compared to what he payed VS what I payed he was PISSED!!!!

Maybe they changed for whatever reason but they were the same at one time.

Save a shoulder shoot a 20ga.