Gonna test some buckshot, what distance?

[JeepsAndGuns]

So I am wanting to buy some bulk buckshot and have narrowed it down to 4 different loads and 2 different brands. I have ordered two 5 round boxes of each one to test out. I will shoot one box out of each of my two main shotguns I plan on using the ammo in. (benelli M3 and mossberg 590A1)
The ammo is not going to be used for hunting, so extreme long range tight patterns is not important, as well as their performance on deer. It is not the dirt cheap crap, but far from the expensive stuff. I will mainly use it for plinking and range fun, but I want to see if any 1 of the 4 types I ordered perform noticeably better than the others out of my guns. They are all the same price and I could not pick one over the others based on limited online reviews. So that is why I decided to just try a couple boxes of each for myself to see what my guns like.
I will pick up couple packs of some cheap poster board to use as a target. I will use one poster board per load for each gun (that's going to be a lot of targets!). I will probably fire 2-3 shots at each target. I just need to know what would be a reasonable distance to test them at? 20 yards? Is that too far? I do not want to be so close I can not tell the difference between the patterns, but I do not want to be so far away, half the pellets miss the target. Both shotguns have cylinder bore barrels.
So can anyone recommend a good test distance?

I also ordered about 3 different types of slugs as well for the same purpose and test. (both shotguns have ghost ring sights) so I want to test those as well. They are smooth bore (I do not have or plan to get any rifled barrels). So what would be a good distance to test the slugs at as well?

If ya'll want, I can post up the results after I am done. (not sure if it would be of any interest to anyone here)

[mudpig]

With cylinder bores you should be good out to at least 25yds. In all of my law enforcement training our shotgun targets were at 25yds and was not difficult to keep all pellets on a standard silhouette.

[scootergisme]

When I first became a cop in 1997, we shot 12 pellet 00 buck shot. Usually had some flyers at 25 yards. Years later, we went to 9 pellet 00 and I would have an occasional flyer at 25 yards. Now, we shoot 8 pellet 00 and I can keep all pellets in the scoring ring at 25 yards (20" cylinder bore). My Remington 870 Police Magnum has ghost rings too. With Remington rifled slugs (the barrel is smooth bore, not rifled) I can hit a small pepper popper at 200 yards. The 200 yard shot with 12 gauge slugs was a part of the course when I went to firearms instructor school. Our department does not even issue shotguns anymore. They now issue AR-15s in lieu of shotguns. I'm old school and believe that a 12 gauge shotgun with 00 buck in the magazine and a side saddle full of slugs in our best weapon!

[Stumpkiller]

The standard for patterning shotguns is a 30 inch circle at 40 yards. But for buckshot 25 or 30 yards should be a good indication.

This area was slug shotgun only for whitetail for some time (right up to two years ago) and 100 yards is the long-end for those. 75 yards would be fine for most. Even with my delightful old pump Ithaca M37 Deerslayer (tight smooth bore with sights) I could hold a 5 shot 5" group at 100 yards from a rest with Federal slugs. And be sore for a week afterwards.

[big honkin jeep]

I Think Walgreens has Advil on sale.

20-25 yards should tell you what you need to know.
For home defense purposes there are lots of loads that are adequate and then some.
Ever since I saw what a 3" 2oz load of copper plated #4s through an extra full choke do to a hog while turkey hunting at about that distance I have kept some on hand. I have no doubt that a good duck load or #4 buck would also be more than adequate for most "self defense" distances

[Stumpkiller]

Odd story but I killed a 200 lb fallow deer with #5 high-brass pheasant shot and a 20 gauge double. From 4 yards it left a hole I could put both fists in where it's heart was. Inside the house 1-1/4 ounce of ANYTHING across the living room will be lethal. Buckshot may carry through walls . . . if you want that.

I understand one of the preferred loads in Vietnam was #4 Buck (0000). Made a big mess up close in the greenery when you just wanted close cover. That's what I would choose for a defense shotgun. But I use #5 High Brass handy beside my double.