Trapdoor Springfield with modern ammo

[J.G. Terry]

KB's in BP guns:

KB's in BP guns: Usually BP actions are divided between strong actions and weak actions. Usually, the poster child for weak actions are TD's. The strong actions include Winchester 1885. Recently, a Ballard rifle KB'ed at a match. Injuries were involved. At the time much was in the press about about cast Ballard actions and how to identify. If you want a smokeless 45-70 try one of the high quality replicas. Pedersoli, C. Sharps, Shiloh and the like. Leave the old ones to the original propellants. What's to gain over stressing these 125 year old rifles?

I you are dead set on smokeless: For smokeless consider 5744. Make sure of double check your information on the Accurate website. Some older data is too heavy for TDs despite claims. Double check.

 

[Road_Clam]

My go to smokeless TD load is 28 gr of 4198 with the 405 cast rnfp. I'm at about 1230 fps. Nice consistent load that won't dislocate your shoulder.

 

[T. O'Heir]

The FTX is about being safe to use in a tube mag, not pressure or velocity.
Hodgdon's Trap Door 325 grain jacketed loads(that just happen to be tested with an FTX) run 13,700 CUP to 26,300 CUP, depending on the powder. 1,958 FPS MAX load velocity with 56.8 grains of H335.
The Hornady 325 grain ammo starts at 2050 FPS out of a 24" 1895 Marlin.
H4895, 3031 only of those powders. According to Hodgdon. You're really best to use the powders suggested by Hodgdon as they've actually tested the loads.

 

[105kw]

A wise man told me when I was very young,
Use lead only in any gun made before 1900, with some exceptions old barrels are soft steel, jacket bullet may erode the bore.

I love shooting old 45-70s, have fun, they are great guns

 

[Tidewater_Kid]

There are people who believe it is wrong to run anything but black powder in these old guns.

Modern ammo for them is loaded to "safe" pressure, but according to some people who are really involved with these old guns, modern smokeless loads while safe (in the blow up the gun sense) they aren't good for the gun, otherwise.

The old rifles fail (crack, not blow up) at a fairly constant rate, they say, and that rate is slightly higher when used with safe smokeless loads than when only black powder is used.

They say that while the max pressure in smokeless loads in in the safe range, the kind of pressure (duration, etc) is different enough from black powder to put an undue strain on the action of the very old guns.
(and again, we're not talking blow up, we're talking could fail (crack) sooner than it would shooting only black powder loads)

I don't know if its true, or not but if I owned an actual 1870s rifle, I wouldn't risk it.

There is some great wisdom in the thread. I wish it will spill over into some of the Trapdoor groups on Facebook. By the way, I have fired some of the Remington "Safe for all rifles" in my 1884 Trapdoor, but after I discovered molds, and Geox, nothing but BP since.