I tested a few slugs this weekend out of my short barrel (18.5") 12 ga Tracker 2 on SB2 frame. I used a Simmons 2.5x scope, bore sighted it, and went to the range.
First up, Brenneke KO slugs (1oz @ 1600 fps) at 25 yards to get the scoped sighted in. You get two holes per shot - 1 is the wad and it looks pretty similar, so it was difficult to sight in accurately. I bought these because they were cheap and I thought they'd be good to seat the action after I shimmed the barrel.
Then I moved to 100 yards and tried them again. About 8" groups, not so great.
Then I tried Winchester 300gr @ 2000fps copper w/ tin core. The first one was on the paper and low, but I couldn't see my next few shots. I thought I missed the target.
So I switched to Federal 1oz 1550 fps (BRI style), and those did OK, I'd say 6". Still not very confidence inspiring. Those printed a bit low, so I adjusted the scope again.
Then I noticed a tight group on the bottom of the cardboard, off the paper. I guess I didn't miss the target with the Winchester 300 gr again after all, they just shot really, really low compared to the other slugs. So I shot a couple more of them (all I had left), but they didn't group like they did before.
I switched back to the KO slug w/out changing the scope, and it shot 8" higher and about 5" to the left of the Winchester 300 gr sabots. Now that is so weird to me, that two slugs will behave just so differently out of the same gun. I would have thought the KOs would shoot low compared to the Winchester (seeing as they have a rainbow arc to them), but that was not the case.
I still had some Buckhammer slugs left to test, but my shoulder said no.
At this point I looked down the barrel and saw the massive plastic fouling in the barrel. I'm not sure which slug did this, but that's probably why the Winchesters shot so badly at the end. It took a lot of scrubbing to get it out.
Lessons learned:
1) stick with just one slug in this barrel
2) the 300gr Winchester probably works well enough out of a clean barrel
3) pay attention to the plastic buildup after each shot
4) 12 gauge slugs out of a 6.75 lb gun... ouch
