I have the Frontier with octagonal barrel too (H001T). Had to scope it (eyes, damnit...) with a cheap fixed 4x Simmons. That is one rifle that will never get sold, it's an excellent little plinker. 15 rounds in the mag, accurate (2 MOA with good ammo from a rest), smooooth action. I love it!
In the interest of posting balance, I have to note three very minor mishaps:
1. After about 500 rounds through it, I started noticing some grinding in the action, it just didn't feel quite as smooth as before. Looking closely, I saw some very small metal shavings collecting on the upper surface of the lever right by its pivot point. I sprayed a little WD40 in the chamber and from underneath that pivot, and the problem immediately disappeared. I'm at almost 3000 rounds through now, and the action is perfectly smooth.
2. I've had some occasional feeding issues with copper-plated hollow-point rounds: the flatter tip of those round gets wedged right above the chamber. You have to back up the lever and line up the round with the chamber using a finger. The solution to this was simply to use a brisker movement when using the lever and to slightly tilt the rifle upward. No issues since.
3. I've managed to lose the gasket that sits at the end (front) of the loading tube (need to email Henry for a replacement, keep forgetting it). No effect aside from giving the tube a slight tendency to rotate and unlock itself when the magazine is almost empty. Compensated by using pliers to very slightly crimp the front end of the tubular magazine so that there's more friction with the tube insert.
All that aside, as I said: I absolutely love that little rifle. I thought the octagonal barrel just looks RIGHT on a lever action, too. Now I'm looking for a pistol-caliber lever action (I got into reloading) and those Big Boys look awfully nice....
