Well, Smokey,
Based on what you've posted.... I've never heard of anyone shooting black w/jacketed bullets. I'd guess that is a no-no! (Pressure concerns for one...)
A 1~18" twist is gong to require the use of heavy bullets. Likely 500 grainerers...
Trust me, those recoil like the proberbial Missouri mule..
I would question the sanity of desiring a rolling block, altho' they are not intrinsically bad... It's just that the Winchester Hi-Wall, is a better design. Several American companys import Italian made Hi-Walls that can be had for $800-$1000... I believe they are good, servicable rifles...
But if it's a rolling block that you want, then that's what you should buy. but figure on using cast bullets w/ black powder. The down side, is that it's a Bit@& to clean up after the shooting session. Cases should be dropped into white vinegar immeadiately after firing. Then washed and tumbled clean. Also, about every 5th shot down the tube, you should wipe the bore with a patch saturated with Windex. Improves accuracy, and makes the final cleaning much easier...
Hope this helps...
GH