High Brass vs Low Brass
It used to be that High Brass on shotgun shells designated a more powerful shotgun shell; such as, waterfowl and turkey loads with 1 1/4 oz. or heavier shot loads. Low brass designated "field" loads; such as, what one would use for quail, squirrels, rabbits, which had 1 1/8 or less loads (12 gauge).
Such designations no longer hold up. Foreign companies target loads, whether made in loading station they have set up here in the USA or overseas, quite often have high brass; in fact, some companies; such as Fiocchi, Gamebore, Sellier & Bellot, Kemen, ArmUSA, Rio, etc. use high brass quite often to designate higher speed loads (1300 - 1400 fps) with less than 1 1/8 oz. shot. Mostly you find these at the sporting clays or bunker trap (ex-international trap) ranges where lighter 12 gauge loads - 7/8 or 1 oz - at higher speeds are coming popular, but these companies have been entering the hunting market recently. You will see the high brass in field loads, again designating the shot speed in excess of the standard 1200 fps.