Anyone no if the LEUPOLD ULTIMATESLAM 3X9X40 SA.B.R. SCOPE #65480. SABOT BALLISTIC RECTILE MADE FOR HIGH PERFORMANCE MUZZLELOADERS
Is comparable better or worse than the Nikon Omega 3x9x40 with BDC ??

No clue...flip a coin.

I have the leupold grandslam. Unless I had to buy a product they didnt have, I would buy leupold every time. I do like the zeiss conquest scopes also, but I don't think they make one.

I'd get the Nikon if it was me.

i would go with the ultimate slam by Leupold. If you will look at both reticles the SABR is much better IMO because that BDC is a little "busy" for me. The SABR is almost the same but the dots that represent the yardages gets smaller the longer the ranges are. The BDC has a constant circle all the way down. This is important so that you have a clean sight picture at farther distances.

I have that scope on my Thompson Center Omega and it worked great.