I just viewed a person that stated he was new to shot gun shells, and ask the question what was the difference between low base and high base shot shells,everybody told him the difference between high BRASS and low BRASS It looks like the old timers haven't any more knowledge than the new comer.
A proper answer would take a lot more space than is appropriate for a forum entry. So here is the "nutshell" version:
Early shotshells loaded with black powder and later Bulk smokeless powders, had the same internal capacity - and needed it. Indeed, Dupont Bulk Smokeless powder was still in production into the early 1950s.
Dense smokeless powder shotshells entered the scene in the early 20th century. To use dense smokeless powders required using an inordinate number of filler wads or a higher internal basewad. Long heavy wad stacks were found to distort shot patterns - the infamous "doughnut" pattern.
The 1920s saw the introduction of slower progressive powders for shotshells like Winchester's Super-X line. Larger shot charges and dense progressive powder needed only a minimal card and fiber wad stack to utilize all the space in a low-base hull.
Remington's introduction of plastic wall-fiber basewad hulls around 1960 did not change the need for high base hulls for lighter shot charges and low base hulls for heavier loads .Even with the coming of plastic wads in the early 1960s did not change the low/high basewad situation immediately as card and fiber wads remained widely used. in addition, there were some short cushion section plastic wads, like the Winchester AA12R, that were designed with high basewad hulls in mind.
Traditionally a
high brass shell had a
low basewad - for various reasons. Conversely a
low brass shell had a
high basewad. Today, the high / low basewad conundrum is but a fading memory. High brass and low brass shell casings are merely a
marketing nod to tradition - even on unibody plastic cases.
