I've loaded a goodly amount of .38 Long Colt brass to feed a Colt New Army Model 1901 revolver. If the Lightning has bored through chambers with no shoulder like the New Army (which I think it does) then you're in business, even if you have to use .38 Special cases. You may trim the cases to .38 Long Colt length if you like but it is not necessary.
Due to bore diameter the easiest way to obtain practical and useful accuracy is to simply load the .358" diameter 148 grain hollow base wadcutters. My Colt has a bore of .363 and keyholes with .358 diamater solid base bullets. If you are looking for a bullet that has more of a period "look" about it then go with the Gad bullets. Good stuff from Gad, they are too.
The 148 grain hollow base wadcutter gives really nice accuracy with the unique bore size of the .38 Long Colt revolver because the bullet skirt fills the bore. Seems to me that Bulls-Eye accomplishes this best of all and at the kinds of pressures you want to hold to.
The .38 Long Colt is a bit shorter than the .38 Special. For crimping, simply use handy 9mm expander and seating dies adjusted in the press to flare, seat and crimp the .38 Long Colt case. There is more than adequate adjustment in the 9mm seating die to achieve a good crimp. Of course the regular .38 Special/.357 Magnum sizing die may be used to size .38 Long Colt brass.
I have pressed regular ol' .38 Special cases into duty for use in my .38 Colt. They will work perfectly, only watch overall cartridge length. The target wadcutter load of 2.8 grains of Bulls-Eye works well and safely with the 148 grain HBWC in the .38 Long Colt case. Since I have adequate supplies of original .38 Long Colt cases I really prefer to use them. .38 Special cases will work in a pinch provided one utilizes .38 Long Colt loading data in preparing his loads.
Muzzle velocity of the 148 grain HBWC bullet with 2.8 grains of Bulls-Eye is 753 fps from the 6-inch barrel of my Colt Model 1901.
I have used 4.0 grains of Unique with 148 grain HBWCs in the .38 Long Colt but didn't find it as satisfactory. It burns really dirty at the low pressures generated. Accuracy wasn't as good and the load was just generally unsatisfying.
Muzzle velocity of the load using the 148 grain HBWC and 4.0 grains of Unique is 752 fps, only one foot per second slower than the Bulls-Eye load.
Some may caution you to use only black powder which is fine but I don't like to mess with it except for when in the mood for getting a "feel" of the original performance of the cartridge. The gun is messier to clean up and black powder is corrosive. Don't forget to immediately and thoroughly clean the cartridge cases used as well.
Of course one should always keep any factory loaded .38 Special ammunition out of a .38 Long Colt revolver and this applies to .38 Special handloads unless they are especially prepared for use in the .38 Long Colt. To play it safe I just keep the .38 Special cases away from my .38 Colt.
Additional factory loads tested over the chronograph
Western 150 grain Luballoy: MV 743 fps ME 183 ft./lbs. ES 64
Winchester 150 grain round nose lead: MV 638 fps ME 135 ft./lbs. ES 53
Frankfort Arsenal 4-11 Factory Load: MV 671 fps ME 150 ft/lbs. (fired single example)
Here's a shorter WRA .38 Long Colt factory load and a Winchester +P 158 grain lead SWC-HP factory load.
The Colt Model 1901 .38 revolver
