I am currently shooting an 11-87 with a Simmons 3x9.
I have been using clear Federal 3" new cases, 44.0 grains of Blue Dot, you can go up more if you choose. I find the recoil too sharp for little performance gains.
This load is rough out of an 870. If you can handle the recoil, it will shoot.
Best combo I have found for accuracy in numerous rifled barrels.
Last year I became the tag filler. 1 deer had to be tracked out of 12. Most dropped where they were hit, devastating. The one that was tracked was a poor shot on my part.
3 years ago, I shot a 200lb 8 pointer, he took three jumps and done. This was at 80 paces, perfect shot, the slug was just under the hide on the off side.
I cannot say enough good about the Hastings slugs. The owners are great to deal with as well.
I purchased the metal roll crimp, a case vise and the primed hulls from BPI.
Compress the powder charge on conventional shot shell press and immediately roll crimp. I use a drill press set on the lowest speed you can. Preheat the roll crimp with propane torch and you are off & running or shooting.
Where I live in central NYS, our County just went to rifle hunting last year. The farm I hunt is still shotgun only(owners wishes) Most of our shots are out to 100 and less. With my current combination, I feel I give up nothing in the woods.
Good luck!!!