Making up a and firing a few light loads would probably be OK, just so you could say that you had fired it. But I wouldn't make shooting it a habit. What has been said previously is correct. If you break something it may well be unfixable as very few gunsmiths today will touch one.

Some of these revolvers have chambers bored straight through, and therefore .38 Special cartridge cases can be chambered and fired. You can easily check to see if yours is one of those by seeing if a .38 Special case or cartridge will fit.

The original .38 Long Colt cartridge used by the U. S. military at that time used a 17.8 grain load of black powder with a 150 grain bullet. The velocity has been given as 723 ft/sec at 25 feet from a 6" barreled revolver. If I were loading for it, I would use a 148 grain wadcutter bullet (preferably with a hollow base) in a .38 Special case (if it fits) with a charge of no more than 2.5 grains of Bullseye.