Here's some test results using a Winchester 101 choked 'extra full' (0.036" of constriction) and 'skeet' (0.003" flare, i.e. bbl opens up). Two sets of data: ammo with plastic wad and ammo with felt wad, both English No 5 shot (2.8mm, 0.11"). The pairs of values for each distance are for 'central hole' and 'maximum extent of pellet distribution'. (The data is tab separated.) Mostly only one or two shots at each distance: I would like to have fired 10 rounds at each distance but there wasn't time. It'll give some idea anyway.
Plastic wad
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Distance (ft) Full/plas
Full/plas Skeet/plas
Skeet/plas
1
0.7
0.7
0.7
0.7
2
0.7
0.7
0.8
0.8
3
0.7
0.7
0.8
0.9
4
0.7
0.9
0.7
0.8
5
0.7
0.7
1.6
1.9
6
0.9
1.4
1.5
2.5
7
1.0
1.5
1.7
3.0
8
1.2
1.9
1.8
3.6
9
1.6
2.2
2.0
4.8
10
1.7
1.9
2.2
5.5
11
1.4
2.5
3.5
6.0
12
1.5
2.2
4.0
7.5
13
1.5
2.3
5.0
8.0
14
2.3
3.2
6.0
9.0
15
2.5
4.0
6.0
9.0
Felt/fibre wad
==============
Distance (ft) Full/fibre
Full/fibre Skeet/fibre
Skeet/fibre
1
0.5
0.5
0.7
0.7
2
0.6
0.8
0.8
0.8
3
0.9
1.0
1.0
1.1
4
1.1
1.0
1.2
1.3
5
1.2
1.6
1.4
1.7
6
1.2
1.7
1.7
2.3
7
1.2
2.0
1.9
3.2
8
1.6
2.0
2.0
3.8
9
1.5
2.1
2.5
4.0
10
1.7
2.5
2.1
5.0
11
1.6
2.5
2.2
6.0
12
1.8
3.3
2.3
7.0
13
1.8
3.7
4.0
8.0
14
1.9
4.3
5.0
7.0
15
1.8
3.0
5.0
8.0