Personally, 4x may be a bit too high of power, but it's what I'm used to thanks to the previous owner of the 835, and it certainly works well. Topped it with one of the Truglo 4x diamond reticle shotgun scopes that works like a charm, and brought a 22lb-er to the table just this last spring. Picked up an old Winchester 1300 turkey specific shotgun for a song a couple of years ago and decided to set it up the same way. Necessary or not, I've always used 3.5' shells with it and I've never had an issue through the years, and I've been fortunate enough to harvest an awful lot of birds through those years with it. I absolutely loved the set up, and still do. Maybe an old Simmons or something else on the lower end. I would guess it to be a fixed 4x that has a diamond reticle with very generous eye relief. I have no idea the brand of optic as it had been painted to match the old dated Realtree camo of the 835.
I wound up trading my Ruger Old Army that I purchased at 17, for a used Mossberg 835 which the previous owner had set up with a scope. I decided that I loved the sport and needed to upgrade, but with a new wife, mortgage and life at that time, had no disposable income. Only shotgun I had at the time with a 3' chamber. I shot my first two wild turkeys with an old single shot 20ga that I had purchased at 15.
