Federal New LE ammo with FliteControl
00 buck vs. 000 is an interesting anomaly. Standard load is 9- 00 (or 8 pellet) buck vs 8- 000. Very little difference in numbers and the heavier and larger 000 would seem to be advantagious. Go to 3" mag and the 000 buck goes from 8 to 10 (not much), while the 00 jumps to 15, and has a definite advantage. Be advised that 000 does have more penetration which may not always be desirable.
From my Scattergun Tech/Wilson Combat 870, 18" cyl bore bbl., a typical pattern with low recoil LE ammo would be about 5" at 10 yds, 9" at 15, and 11" at 20 yds. 25 yds is stretching it. This applies to Federal Tactical and Win. Ranger LE ammo. Standard vel. buckshot spreads much more. The difference in barrels can be significant, especially with re: to uniformity. The difference between two Mossberg barrels like yours could be as much as the difference between your Mossberg and my Scattergun Tech.
Be advised that, last year, Federal incorporated their FliteControl wad into their tactical line. Elmer mentioned it in his post. My tests with this new stuff were incredible. Under 2" at 10 yds, 5" at 15, 7" at 20 and about 9" at 25yds. Effective patterns at close to 40yds. The wad controls the pattern. The choke does not. The shot doesn't start to spread until the wad opens up and slips off the shot down range. My tests showed no difference between cyl bore, mod., or full choke barrels. You've now got, for practicl purposes, a slug out to better than 10 yds, and buckshot thereafter.
My tests were with the LE 132-00 9 pellet loads, but it's available in 133-00 8 pellet. I suspect it'll be used in the 132 000 load also. You may not want tight patterns like that for home defense--Federal made the change to give all those Police cyl bore shotguns more range. They succeeded. Hornady has followed up with their TAP load which also produces super tight patterns, but I doubt as tight as the Federal. In short, the Federal and Remington, Winchester LE loads tightened patterns over standard buckshot. Now the new loads tighten patterns even more (lot's more). All of the LE ammo is pleasant to shoot in slugs or buckshot.
I bought mine at a gunshow. The new FliteControl should be showing up on line at places like Ammoman after they get rid of the current stocks, which might actually be better for HD--at least they spread a little.