I was able to locate some reliable data fairly easily. Ned Roberts, in 1913, had a Niedner chambered 25 Krag and recommended a load of 28 gr. Lightning under an 86 grain 25-20 bullet. Roberts estimated the velocity to be 3,000 fps.
Chas. Newton's 25 Special on a full length 405 case (I once had a High Wall thusly chambered) burned 43 grains of Lightning to speed a 117 grain bullet at 3,100 foot seconds. The velocity was measured over Winchester's chronograph.
A period factory ( which one isn't recorded) loading for the 25/35 used 19 grains Lightning for 1,925 fps.
If you have Jenning book on Newton, you might get additional chronographed loads using this powder. Newton was big on the 25 Krag for some time and I know for certain he burned a lot of Lightning.
