It's a good day on Earth when Dr. Dave makes a recommendation about shotguns, especially 870's, cause we all get to learn.
I'm going to take the initiative to (re)iterate two of his points that I totally agree with (because he {with the help of notable others here) taught me much about 870's,and because my own experience is another data point in favor of his assertion}:
IMO, most folks bigger than Tinker Bell can handle a 12 gauge 870 IF the stock fits them.
Some dry mounting at home will help condition the muscles needed.
I'm 6' and hovering around 135. Slightly larger than Tink, but well below Terminator.
I find my 12 ga 870 (18") a joy to shoot. Yeah, a shotgun workshop with over a hundred rnds would (meaning I've not done one ... yet) rattle my brain, but a couple or three boxes o' shells ('specially RR) put through the barrel with appropriate attention to snugging that baby up close, in tight (just like you'd prefer any welcome love or ally) ain't nothing to worry about.
Plus, mine's got an R3 pad on it, highly recommended for those of us closer to tinker than terminator.
And yes, those dry fire sessions at home (done
ONLY after
tripled checking that said shot gun is unloaded) will substantially help that firing comfort.
Remember: snug 'er up tight on the shoulder, and lean into it a bit.
Make sure your fingers are well up on the fore end when racking. (You'll likely make the "pinch mistake" once if you don't.)
Happy Saturday everyone.
Nem