After an AAC rep brought the handi rifle to a class I was attending, I bought a HR in .357mag, and sent the barrel to Accurate Ordnance. They cut and threaded it at 16", I put the Choate youth stock on it, so it's about like the .300
I've went back and forth between a Bushnell TRS25 and an old Redfield 2-1/2X scope.
With the magnified optic, you'll have to run the scope's occular bell behind, in front or over the hammer.
Running it behind, with the full length stock works ok, you can keep it low, and the eye relief works out. For me the standard stock is to long, and underminds the point of the gun.
Running it in front, I had to use Weaver dual extended High rings, so the occular would clear the rail, and it could be mounted far enough forward to clear the hammer & for the eye relief to work with the short stock, which is just about too short..but it makes the rifle tiny.
I have not tried extra high rings, but I'm sure it would be about the same as the other ways..it would add a lot of bulk to the gun.
I wanted a magnified optic, because red dots are starting to look less and less clear to me...but in this case, the benefits don't outweigh the draw backs..so I went back to the Bushnell.
Lotta info on the handi's on Grey beard outdoors(?)
Bob