I have a Heritage single-action 22lr/22mag also. Decent little gun -for the money. Mine's been accurate, at least so far. Fun to shoot. However, I wouldn't call it a high-quality firearm. Locks up ALL the time. To the point where you have to manually pop out the cylinder and start all over from scratch.

44 mag seems to be a lot of cartridge for a Vaquero - or is that just me? Could that maybe be partially responsible for the less-than-spectacular groups?

I have a Ruger 44magSuper Black Hawk and the difference in quality between the Ruger single-actions and the Heritage is not even close. I don't currently own a Single-Six, but I've seen enough of them to know that their quality is a level or two above the Heritage also.

Again, I like my little Heritage, despite the lock up issues. When it works, it'sa fun little gun and shoots well. But it's no Ruger. I'd probably trade it sight-unseen for pretty much any single-six/Vaquero/whatever.