I have used both the Barnes MZ 250 gr bullet and the Precision Rifle " Dead Center" bullet in 220 gr.
I had excellent accuracy with both from my Encore 209x50 ML.
Differences: Barnes was most difficult to get down the bbl, while the " dead center" easily goes down the tube.
Barnes has a terrible drop at 150+ yds while the " dead center" is still screaming at 200 yds
Both bullets and their sabots handle 150 gr. of pyrodex very well.
The polymer tip on the " dead center give the bullet a better " B.C." , flatter trajectory and hotter velocities.
p.s. I bought my " Dead center" bullets directly from the manufacturer, and funny enough, they are located in Canada!