its pretty much interpretation of the regulations i guess.
44cf isn't 44-40 but could be . yikes
A handgun manufactured before 1898 that is capable of discharging centre-fire cartridges, other than a handgun designed or adapted to discharge 32 Short Colt, 32 Long Colt, 32 Smith and Wesson, 32 Smith and Wesson Long, 32-20 Winchester, 38 Smith and Wesson, 38 Short Colt, 38 Long Colt, 38-40 Winchester, 44-40 Winchester, or 45 Colt cartridges.