Remington/DuPont acquired Parker shortly after the 3-inch .410-bore shell was introduced by Winchester-Western/Olin, giving Remington their first .410-bore shotgun. I first see Remington offering a 3-inch .410-bore shell in the
Remington Kleanbore Shotgun Shells & Cartridges dated 8-34. While they offered the same 3/4-ounce load that the Olins brought out, they also offered a 5/8-ounce load for which they claimed, "the 5/8 oz. load has 10 per cent higher velocity, has the best Ballistic Balance and throws practically the same effective pattern as the 3/4 oz. load."
8-34 Kleanbore Shotshells & Cartridges, 5-8 ounce .410-bore load highlighted in yellow.jpg
The 5/8-ounce load is also in a 1935 dated price list but is gone by the next one I have dated 1938. I bid on a full box in a Ward's Auction, but others wanted it far more than I did.