I am a brand new member of this forum. I am 84 years old and still an active hunter and gun enthusiast. I own an as new, never fired, H&R 1873 Trapdoor Carbine which I want to start shooting. I have been told that H&R's Trapdoor Springfield has a weakness in the locking cam mechanism that the original Springfields didn't have. I have also read where someone on this site can explain this issue and tell me what the fix is. I have always known that the original trapdoor actions are inherently weaker than other types of actions and require lower pressure 45-70 loads. I do plan, in the future, to follow all the recommendations in my Lyman Reloading Manual for Trapdoor Carbines, but for now, I am going to start shooting it with cowboy action ammo available at Midway USA. First of all however, I need to figure out what if anything I need to do about the locking cam issue. I sure would appreciate any information and advice you guys could give me. Thanks again, Ron