After reading all these posts, I'm going to take the advice of the posters for now and learn the Benelli.
I'm not TERRIBLY inefficient with it mind you.... but it's not the same as my Browning HP that I could strip, assemble, and run a match with in my sleep.... okay, maybe I'm not that good but you get the point.
Question 1: Anyone have some links to useful drills?
Question 2: What choke to use? Right now I prefer improved cylinder because of my strong belief in slugs. In my experience, slugs are much more accurate for field use; whereas one only has a limited amount of control over the pattern of pellets. If I did use buckshot, it would be full choke.... but full choke leaves me unable to use slugs - and in a TEOTWAWKI scenario, versatility could be appreciated.
Until I get more training, I'll keep it in the safe and take it to the range. I'm going to look into classes at my local range as soon as I get some cash (just got a Ruger LCP so I'm broke on fun money).
Right now it's sporting an 18.5" barrel, pistol grip, and standard mag tube. I really need a sling, preferably one that would allow me freedom of movement and the ability to draw a pistol while the weapon was slung.
I have considered putting the surefire forend on it, or getting tritium front sight - but I'm kind of on the fence right now.
I just started doing IPSC with pistols, but eventually I'd like to be try a 3-gun shoot.
The only advantage the pistol grip mossberg seems to have is size.... the main reason I got interested in the M500 is because one of the only guns I don't have in my collection is a large caliber revolver for grizzly bear defense - and a pistol grip M500 slung over the shoulder with 3" slugs seemed a more economical choice.
I also liked the safety because it works the same way as my Stoeger Coach Gun, which strangely enough is my favorite shotgun I own.