Originally Posted by 30-30remchester
I answered your question in another thread. Whether new or old, the trapdoor design is weak. I shoot several trapdoors on regular occasions so have some working knowledge about them. If you start reloading get Ken Waters book " PET LOADS " he does and excellent job of explaining the presures and strenghs of varios 45-70 rifles.
If my informant is correct, and I am sure he is, Ken Waters blew up a TD a few years back with a "pet load" for the TD he used for 20+ years, 24 gr of 2400 IIRC.
The TD is NOT safe with smokeless. Like many 19th century designs, modern made or otherwise, there is no safety margin.
Thin 19th century steel barrels and an action that is designed to "auto open" (do some research and note "copper cases with no spring back" jamming the breech block).
Yes it can be "gotten away with" but its a risk.
Some years back when the import TDs hit the market I had two different shooters at the BPCR Nats tell me that they had their new import TDs auto eject with BP loads one told me the case cut a groove in his hair.
I have heard third hand stories of the H&R TD doing this.
The "cam" must be CAREFULLY fit to the mortise in the breechplug. Any "goof" in the angles and the action may not stay closed. Modern steels cannot overcome this.
Remember the Gov't was constantly upgrading the action till it was replaced by the Krag. Some experts on the action do not consider the early versions safe even with BP.
Remember that many TDs have oversized bores. So you may have problems with jacketed/hard cast bullets and/or smokeless powder.