I would think that shortening the barrel would increase the recoil due to the lighter weight. I think it needs that stock weight in there, unless you are going to replace it with a mercury recoil reducer.
Check out the FAQ at the top of the H&R Centerfire rifle forum. A lot of information there and a good share also applies to the H&R/NEF shotguns.
Welcome to the forum. There are a lot of good people here to help you out.