Could be. I just never thought those were 1 1/4 oz. Hard to say. Less charge possibly. Or even a different powder maybe.That's like the old pigeon loads which were always 3-1/4 dram 1-1/4 Oz @ 1220. These may be low brass vs high brass 1330.
High brass https://www.federalpremium.com/shot...wl/game-load-upland-hi-brass/11-H126+7.5.html