Some older Hercules/Alliant handloader guides gave the height of column for 1 oz shot in the various bores. Unfortunately they did not specify shot hardness or size but by assumption was ordinary chilled shot in a smaller saze as used by skeet & trap shooters. You can of course get the length of column for any other charge by sim ply multiplying the shot weight by the given figure.
10 ga = .610"
12 ga = .690"
16 ga = .837"
20 ga = .969"
28 ga =1.212"
.410 = 2.181"
This is based on an ounce of shot occupying about .288 Cu In.
On this basis an ounce of shot in an 8 ga (.835" bore) would stack up to .526" long. A shot load of 1.588 oz would thus be "Square" at a .835" column. With the larger shot sizes normally associated with an 8 ga it would be a bit longer, likely on t5he order of 1 5/8oz.
As an interesting side line standard industry is for black powder measures a dram of powder is deemed to occupy .115 Cu In. thus .2875 for a 2˝ dram load & .345 Cu In for a 3 dram load. Thus the 2˝ Dr-1 Oz load is one of the few factory loads one will see which is in fact based on the equal volume loading. Most use a slightly heavier powder charge in proportion to the shot volume, even in Black Powder days. Virtually all the Black Powder shotgun shooting I have done whether muzzle loading or loading shells I have stayed with the equal volume method with good results, but have loaded no bigger than 12 ga.
