The Henry, 1866 and 1873 are all inherently weak designs. You don't want to use anything other than standard loads at best. "Standard" would be characterized as something like 250 grain bullet at around 850 fps, IMO. These were the standard smokeless loads put out by Remington and Winchester for years. Nowadays, you have factory loads that are healthier than that and I would NOT recommend them in any of these guns, regardless of condition, maker or originality (as opposed to replica). The replicas are stronger only in that they are made of better materials than the originals, but the extra strength is nowhere near enough to make up for the design weakness. They are fine, historical guns within their limitations, but the limitations are real and must be strictly adhered to. The next step up in 45 Colt loads would be "Ruger Only" and in no way would you ever use one of these in the aforementioned guns. Don't even use warmish loads. Cowboy action type loads should be ideal.
