I have been hunting with a 12 ga H&R Ultra Slug rifle for many years now, and have been delighted with it. It shoots Foster-type slugs very well, but my favorite hunting load is the 2-3/4" Federal Premium with 325 gr, 0.500" Barnes Expander ML bullet at 1900 fps. This is a real killer.

The H&R is an extremely reliable, very accurate rifle. Mine was fired extensively the summer I got it, looking for favorite ammo. It consistantly held 2 MOA at 100 yards. I fire three shots with it every year just to check zero, and it maintains that standard. It will shoot better groups, but I consider the worst group to be the important one.

There is no reason not to use brass cases; the gun is chambered for 3" shotshells so a brass case up to that length should be fine. The only ones I've ever seen were the 2-3/4" OO buckshot my father used in the Navy.

There was a thread on customizing this rifle sometime in the past year. You might want to look it up. I've never tried roundball ammo in my H&R. I'll look forward to your report.