I picked up a tin of 5.52 Falcons and tried them against Mosquitos in my Steyr LG100 on Saturday.
I've been using the 14.3 Mosquitos for some time now but wanted to see if the 13.4 weight of the Falcons gave as much accuracy. Shot five group of 5 pellets in each type and overall the Falcons were just better at 35 yards. POI was slightly higher as you'd expect. The Steyr was set up at 606 fps max on Mossies and the Falcons went through at 626 max without any adjustment. That's an identical 11.66 ft lbs with both.
I think I will be switching to the Falcons very soon once I've checked accuracy out to 45 yards and mapped POIs for HFT ranges.
Very similar dimensions to the Mossies but you can see the weight saving is made inside as the rear end goes deeper into the pellet.