Newbie confused with conflicting load data

[CaribouJerky]

Hi I'm new here and have been learning about hand loading. As a practical exercise I have been looking up load data on powder and bullet manufacturer websites.

I think I have found the same load on both the Speer and Hodgdon websites but the load data is wildly different.

I can't help but think I made an error, but I can't figure out what I did wrong. This concerns me and I was hoping someone could double-check my findings and point out my mistake so that I don't make it again when actually reloading.

The load I looked up was for a 45-70 (lever action) with a 400gr Speer Jacketed FN and IMR 4166 powder.

The Speer website lists a starting load of 43.5gr and a max load of 47.8gr

The Hodgdon website lists a starting load of 49gr and a max load of 56gr

The websites I used were Speer (https://www.speer.com/reloading/rifle-data.html) and Hodgdon (https://www.hodgdonreloading.com/reloading-data-center?rdc=true&type=54)

Thanks for any help

 

[ArchAngelCD]

The 45-70 is a little different than most other cartridges. The load data is in 3 different pressure limits. The lightest loads are meant for the Trapdoor, next is for the levergun and finally for the modern rifles like the River No.1. Sometimes the different sources conflict because they use different pressure limits. The Speer data only separates the data into 2 pressure ranges while Hodgdon supplies 3 pressure ranges. That is the reason why the data is so different.

I suggest buying a Lyman manual because they supply all the pressure limits they use and pressures for each load they supply.

Welcome to the forum. I hope this helps you a little...

 

[BBarn]

There's no industry standard for acceptable 45-70 pressure specific to lever action rifles. Each manufacturer recommends loads they believe are safe in such firearms. Hodgdon (38,100 psi) has chosen to set the acceptable pressure higher than Speer (28,000 CUP), so Hodgdon's powder charges are higher.

 

[DukeConnor]

I have recently begun loadimg for 45-70 and found this site very useful.

http://www.gmdr.com/lever/lowveldata.htm

 

[stillquietvoice]

@CaribouJerky welcome to the forum.

Loads vary a lot by manufactures, the variances in large part are dependent on their specific test media, rifle, pressure test barrel..... no matter what their test media they all provide data that proved to be safe for their tests. As was mentioned 45-70 has a lot of data for old "weaker" type rifles, old rifles, or newer modern strong type actions.

 

[lordpaxman]

@CaribouJerky, welcome to THR! You asked a great question, and it’s good to compare different sources to see what different sites recommend.
Since the data in your OP was for “LEVER ACTIONS”, in both cases, it’s dependent on what testing method and criteria they used to set the low and high limits. You will notice on Hodgdon’s site, the higher “Max” yielded about 270 fps more velocity. I’m just starting to reload for a Henry in this caliber, and what I’m planning to do is use the Min from Speer and Max from Hodgdon although it’s not for your 4166 powder. I also use a chrono to see how my loads in my gun are performing relative to the published data, and I’m not looking to max out any loads, this caliber kicks enough at any setting. Good luck.

 

[jmr40]

In your case I think you are looking at load data for different classes of rifles. Generally speaking 45-70 data is in 3 classes:

Original and reproduction trap door rifle data is very mild. It basically duplicates the original black powder loads but with modern smokeless powder.

You will also find data for modern lever actions which is sort of middle of the road.

And finally there is separate data for use only in modern single shots like the Ruger #1 rifles and some custom bolt rifles. You choose the data to match the rifle you plan to use it in.

In other cases one manufacturer may simply stop testing once they reach a certain velocity level. The numbers they print aren't necessarily the max load that is safe, just as far as they decided to go with testing. A different manufacturer may use the same powder/bullet combo and push things farther to determine that more powder and velocity is perfectly safe and the numbers they print reflect that.

 

[AJC1]

What is your intention. I paper punch with trail boss and velosity means nothing. If your hunting you can make loads with 3031 that will brutalize both ends of the gun safely. 45-70 is not the cartridge for chasing speed, and has a rainbow trajectory.

Load data is almost never consistent. I havent used that powder so if I was loading it for the first time I would set 1100fps as a goal speed for my first loads if safe with that powder. It's a good region to shoot normal pressure in and work up as needed from. Even that speed will hit with a ton of power if your banging steel.

 

[CaribouJerky]

The 45-70 is a little different than most other cartridges. The load data is in 3 different pressure limits. The lightest loads are meant for the Trapdoor, next is for the levergun and finally for the modern rifles like the River No.1. Sometimes the different sources conflict because they use different pressure limits. The Speer data only separates the data into 2 pressure ranges while Hodgdon supplies 3 pressure ranges. That is the reason why the data is so different.

I suggest buying a Lyman manual because they supply all the pressure limits they use and pressures for each load they supply.

Welcome to the forum. I hope this helps you a little...

Thank you! That makes a lot of sense

 

[Bfh_auto]

@CaribouJerky, welcome to THR! You asked a great question, and it’s good to compare different sources to see what different sites recommend.
Since the data in your OP was for “LEVER ACTIONS”, in both cases, it’s dependent on what testing method and criteria they used to set the low and high limits. You will notice on Hodgdon’s site, the higher “Max” yielded about 270 fps more velocity. I’m just starting to reload for a Henry in this caliber, and what I’m planning to do is use the Min from Speer and Max from Hodgdon although it’s not for your 4166 powder. I also use a chrono to see how my loads in my gun are performing relative to the published data, and I’m not looking to max out any loads, this caliber kicks enough at any setting. Good luck.

I do the same in other cartridges. It pretty much guarantees finding a good load.
The 45-70 has substantial recoil in a Sharps. I'm out on a lever action.

 

[mdi]

Any time one is confused by "conflicting data", start with the lowest starting load of the "conflicting" sources. Google "Why does load data differ between reloading manuals?",,,

 

[FROGO207]

Good advice from MDI and others. The 45-70 is a good example of different strength loads for different strength actions. A reloading manual(s) are a guide that the person testing that particular set of components on that particular day with that particular firearm found safe. It is your job as a reloader to determine what is safe from their various tests in YOUR firearm. The more you work at it the more you get a "horse sense" that doing a certain thing will yeild a good load. Just keep good records on what you try so that there are no repeats of your failures and a list of good loads to use in the future.