Samson, I agree with Marsh in one sense but respectfully disagree in another. The answer is it depends on the manufacturer and ammo. I've owned and shot several TDs over the years. There are some jacketed "factory" loads that are definitely way too hot to use in a springfield and there are some that are safe. A few years ago all the factory loads were safe since companies like Remington, Federal, Winchester, etc only manufactured smokeless .45-70 ammo that was safe in a TD due to liability concerns. Since then due to the huge popularity of rifles like the Marlin Guide guns and some modern single shot rifles several smaller companies are offering "factory" ammo loaded well in excess of the max pressure capabilities of a TD. There is no question that black powder loads are certainly safe (as you likely can't get enough black powder in a case to overpressure a TD), but if you check with Remington, Federal, and Winchester I believe you will find that all their "factory" loads are safe. Of course they will tell you your rifles has to be in good condition, and if it an original TD should be checked out by a qualified gunsmith. Finally you need to consider that the metal in original TD is softer than modern rifles and extensive use of jacketed bullets will accelerate bore wear.
Hay TexasMac: That is some useful information, and thank you. Marsh has long been a resource for information on BP shooting in the 45-70 and I have printed out just about every recipe and formula he has posted for shooting BP 45-70s.
But, you said that you have, or have had a number of the Trapdoors and I was wondering what particular load you would recommend shooting in yours. Mine is (listen to this) a Model 1884 with a 5 digit serial number on the receiver, an 1884 'Trapdoor', an 1888 Ramrod bayonet and a bore that still shows manufacturing rifling marks. I was told the Springfield factory never threw anything out, which would explain the low serial number but with that barrel with it's sharp and deep rifling I'm wondering which load might be the most accurate to shoot. Paper is my target with that Trapdoor. Thanks. Mikey.
Mikey and Samson, don't read my previous comments as a recommendataion to use smokeless loads. My response to Samson was meant to indicate that with the proper precautions you can safely shoot the right factory ammo comprised of smokeless powder and jacketed bullets. I agree with Marsh that blackpowder and cast bullets is the way to go. I now only shoot blackpowder in my TDs.
Samson, there are many acceptable reloads for smokeless powder and either cast or jacketed bullets. Most of the reloading manuals lists options. Just be sure you are using a load that is clearly stated for older rifles for the .45-70 Government cartridge. Make sure you use a combination with pressure levels under 18000 PSI or less than 16500 CUP. My favorite powder is Accurate Arms XMP5744. Accurate Arms say you can use up to 27 gr. (for 1400 f/s with a 405 gr. cast bullet). My load is 25.5 gr. of 5744 under a 405 grain soft cast bullet. The lube is Thompson PS for blackpowder (even though this is a smokeless load). This combination should give you around 1250 to 1300 f/s or so. The main advantage to using XMP5744 is no polyester wad is required to hold the powder next to the primer as would be the case for other smokeless powders.
For blackpowder loads I use the same combination of bullet and lube but fill the case with slightly compressed 65 gr. of Goex FFg black powder. A .030" cardboard wad (cut from tablet backing) is inserted between the powder and bullet. Velocities should be in the 1200 f/s range.
Over the years there have been several good articles on .45-70 Gov. loads for older rifles. One was authored by John Kronfeld and published in the July 1998 edition of the American Rifleman. It covers both smokeless and black powder and black powder substitue loads for Trapdoors, Sharps, Rollingblocks, etc. using cast and jacketed bullets.
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