John - with that .410 - if you shoot the 2 1/2" instead of the 3", you should find better patterns right off the bat.

Reaming the chokes to modified or having that done will also improve patterns over the orignal full chokes. for a 30/35 yard gun, full choke is normally too tight for such a long shot column and low shot charge weight which combine to give a definte limited range. This, along with the reduction to the 1/2 ounce load which does pattern more evenly, will give you a full 30 to 35yard killing gun depending on the quarry size.

3" (11/16oz?) shells and full choke usually makes for a killer to 25 yards due only to the extreme pattern density in the inside 10" (if you are accurate enough) of the pattern and a horrid wounder of birds beyond that due to the rapidly thinning pattern.
The thin, sporadic outer pattern is caused by bore abrasion of the extra-long shot column through the tight choke. This, coupled with a horrendously long shot cloud (strung out cloud), makes for hitting flying birds a difficult time indeed, especially if they are not on top of you.

The shorter shot cloud of the 1/2 ounce load, coupled with slightly relieved chokes benefits this little "pelter" in evening up the pattern and including in that pattern, pellets that normally would have been fliers.

Something else that patterns well in them, is a .444 Marlin case, 12 gr. of Unique or Herco, .410 wad, 1/2opunce of shot and the fingers cut off just below the case mouth. Place a .44 mag. gas check on top of the shot column and crimp it with either a .44 mag or .444 Marlin crimp die.