As we know, bull barrels in rifles reduce harmonics in general, so it's easier to find an accuracy node, or should I say the harmonic accuracy nodes are much wider. They also generally increase the weight of the rifle along the tube and thus alter the balance of the recoil and reduce it some.
In pistols the obvious they add weight to the tube at the top of the firearm. I don't know if harmonics really come into play in a pistol to the extent that they do in a rifle. So I think the main thing they do is move the center of gravity closer to the barrel and if all else on the firearm were equal, reduce weight.
I have a Sig 1911 Ultra Compact with a 3.3" bull barrel in 9mm and weighs 28oz. It would probably come in at 24 or less if not bull. It is very accurate and a pleasure to shoot. I like the balance of it too. Different than my Guardian's balance, but good. I think the balance of recoil is also affected.
I liked it enough that I picked up a DW ECP yesterday. Can't wait to take her out and compare the 2.
All of my pistols are capable of greater accuracy than I can shoot them, and I'm not unhappy about that.

I can only hope that with that with enough practice I will be able shoot as well as what my guns are capable of. Unattainable I know, but I can have fun trying!