Man, I really appreciate the comments gentlemen! Maybe we can get this thing figured out in the next 3 days! LOL
My M3 has the same type of front sight as the one pictured on Benelli's webpage. They do appear to be adjustable, but for windage only. It does look like if I could find a very small open end wrench and get the tiny nut off, I might be able to put a small shim of some type under the front sight post and reinstall the sight, raising the height of the post. Of course, a taller post would be better, but I'm not even sure if they make one.
Also, I forgot to mention, the sights that I have ARE the adjustable ghost rings. They are the model previous to the ones shown on the website though. The rear sight is fully adjustable for windage and elevation, just not adjustable enough I suppose.
When I was sighting in and got these results, the 1st time I was shooting using the bedrail of my truck for a rest, with my hand underneath the forearm. The 2nd time I was sitting in a chair, using a standing wooden powerline pole as a rest. I can't remember if the forearm or barrel was in contact with the pole, but once again, I was holding onto the forearm with my left hand, and just using the pole to steady my aim. So, with my hand supporting the forearm, I wouldn't think it would have anything to bounce off of, but it's possible I suppose.
For the past 10 years I have used a 20 ga Rem. 870 for deer. Smoothbore with rifle sights. I've never had a problem like this, and have always used Winchester slugs.
Also, this is NOT a rifled barrel. It is a smoothbore with adjustable ghost ring sights. I have fired shotshells in my 870 deer barrel also, and if it affected the impact of the slugs at all, it was not enough for me to notice.
I don't really know what else to say about it, maybe I'm missing something. It has the integral 8 shot magazine tube (not a screw on) that has been plugged to hold 2 rounds to be legal. Also has a pistol grip stock. Everything is factory, no aftermarket accessories on it. It does have the stabilizer clamp from the barrel to the magazine, I can see how this could affect the POI, but not sure if it would make it shoot about 8" high from the factory zero.