What length shell are you using? That extra 2 rounds applies only if you're using 2 3/4" shells or shorter.
If you're using 2 3/4" shells, see if there's grunge buildup at the shoulder where the shell follower stops. Cleaning well and lubing lightly should fix.
And if you are using 2 3/4 ammo that is roll crimped you are probably going to have to settle for one round less. It is longer than star crimped ammo just enough to not let that last round slide in for most guns.
