Many shot sizes are not commercially available. The previous post also made some assumptions about the load.
Here's what I found was readily available in a catalog I had laying around.
12ga 2 3/4"
000 Buck 1d+2 pi 50/900 shots x8
00 Buck 1d+1 pi 40/800 shots x9
0 Buck 1d+1 pi 40/800 shots x12
1 Buck 1d(0.5) pi- 40/800 shots x16
4 Buck 1d-1(0.5) pi- 30/600 shots x27
#2 Birdshot 1.25 oz. 1d-4(0.5) pi- 20/400 shots x109
#4 Birdshot 1.125 oz. 1d-4(0.5) pi- 20/300 shots x152
1.25 oz. 1d-4(0.5) pi- 20/300 shots x169
#5 Birdshot 1.25 oz. 1d-5(0.5) pi- 20/300 shots x213
#6 Birdshot 1 oz. 1d-5(0.5) pi- 10/300 shots x225
1.125 oz. 1d-5(0.5) pi- 10/300 shots x253
1.25 oz. 1d-5(0.5) pi- 10/300 shots x281
Here's what I found was readily available in a catalog I had laying around.
12ga 2 3/4"
000 Buck 1d+2 pi 50/900 shots x8
00 Buck 1d+1 pi 40/800 shots x9
0 Buck 1d+1 pi 40/800 shots x12
1 Buck 1d(0.5) pi- 40/800 shots x16
4 Buck 1d-1(0.5) pi- 30/600 shots x27
#2 Birdshot 1.25 oz. 1d-4(0.5) pi- 20/400 shots x109
#4 Birdshot 1.125 oz. 1d-4(0.5) pi- 20/300 shots x152
1.25 oz. 1d-4(0.5) pi- 20/300 shots x169
#5 Birdshot 1.25 oz. 1d-5(0.5) pi- 20/300 shots x213
#6 Birdshot 1 oz. 1d-5(0.5) pi- 10/300 shots x225
1.125 oz. 1d-5(0.5) pi- 10/300 shots x253
1.25 oz. 1d-5(0.5) pi- 10/300 shots x281
#7 1/2 Birdshot 1 oz. 1d-5(0.5) pi- 10/300 shots x350
1.125 oz. 1d-5(0.5) pi- 10/300 shots x394
1.25 oz. 1d-5(0.5) pi- 10/300 shots x438
#8 Birdshot 1 oz. 1d-5(0.5) pi- 10/200 shots x411
1.125 oz. 1d-5(0.5) pi- 10/200 shots x462
1.25 oz. 1d-5(0.5) pi- 10/200 shots x514
#9 Birdshot 1.25 oz. 1d-5(0.5) pi- 10/200 shots x731