I have nearly the identical barrel, 15" Encore, full bull MGM with their break. I'm shooting a Red Dot with the cross hair reticle.
I have three rings on my red dot and it is staying put so far.
I had some issues with the 240grn XTP's so I went to the Barnes XPB 200grn at the suggestion of someone, can't remember who it was.
Getting a lot better groups. I'm using 45grn H110, OAL 2.330 which is real close to the rifling. I had to wait on more bullets and now I'm going to get some velocities soon. I'm getting about 1.5" at 50 yds with the red dot. This is going to be my close range, under 100yd gun for pigs and deer. I might put a regular scope on it and try after taking some game like this.
The photos show only two rings but I have now installed a third ring. Also the first ten rounds trashed the cheap Bushnell rings. I went to a Gun shop and got four 30mm Hvy Duty rings using torque screws. The red dot sets a little lower now with the new rings.


You don't quit playing because you get old, You get old because you quit playing.