Mossberg 500 12 ga with a 18 1/2" cylinder bore barrel fitted with a tritium front sight. Added a surefire light and loaded it with LE #1 buck with the flight control wad. It shoots a 2" pattern at 12 yds. Definitely has to be aimed.
I also believe the stock is too long. Looking at the Magpul.
After some debate I ordered a magpul stock. I also tried shortening an existing full size SpeedFeed solid stock since the new stock was on the way. To my surprise my hacksaw and sanding skills are not to bad! I was debating returning the MagPul to save some coin. The MagPul arrived today and I am impressed. However, I did get a chance to shoot with some MagPul stocks and they were nice but not noticeably different then a traditional youth stock.
My my suggestion is try shortening the existing stock. If you are successful then great! If not no harm, no foul order a MagPul.