45-70 data discrepancies

[Stripes]

Has anyone else noticed the vast discrepancy between the lyman data and hodgdon data? I've been working up a load with IMR 4198 and Sierra 300gr hollow points using my lyman manual. The max load for Marlin levers is 45gr, after hitting that and not noticing any red flags I've worked it up to 46.4gr with no negative effects.

So today I decided to do some research. Hodgdon lists their starting load for 1895 lever guns at 53.7gr! Lyman has their max load for ruger No. 1 at 53.5gr! What gives? Same bullet, same OAL. Is lyman ultra conservative with their data, or is hodgdon living life on the edge?

Side note, anyone have any experience with this bullet? I'd like to use it for hunting since I've come into a slight windfall of them. I want it trucking along as fast as possible while still expanding properly.

 

[Northman999]

Data discrepancies are very common. I have seen different manuals list 6 to 8 grains difference of the same powder with the same bullet weight in the same cartridge for other cartridges besides the 45-70 as well. Another thing that is some thing I have observed, is that with older cartridges you can see an even wider spread of reloading data out there, I’m thinking that’s due to older rifles or older official pressure ratings.

Here’s an example of a good spread of reloading data. 375 RUM. Hornady manual lists a maximum load of reloader 22 of 91.8 g for 2700 ft./s velocity. Sierra manual lists a maximum load of 99.2 g for 2950 ft./s velocity. I can tell you that at 250 ft./s spread in velocity with a 300 grain bullet is a huge energy difference. I can also tell you from experience that the Sierra manual is the one that’s actually accurate.

 

[Janeau]

Contact Hodgdon. They do not list Ruger # 1 load on their web site - might be data for the Ruger # 1 after all. Another possibility is a mix up of IMR 4198 and H4198.

Myself I would use Sierra data ( for Marlin 1895 only ) that show best accuracy load for their 300 grains bullet at 49.9 of IMR 4198.
Max is 51 grains. Sierra does not list Ruger # 1 or # 3 in their web data either.

Max powder charge is 1/2 of the story. Chrono you load. They usually use longer tube than most, so if you obtain the published data velocities, I would stop there.

300 grains is a light weight for the 45/70, most perform better in the 405 grains range.
Some gun need a front sight change for the light weight bullets.

 

[Retriever]

There are huge discrepancies in the max loading data ( and pressures ) for the 45-70 between different loading manuals.Hornady list's data with pressures up to 40000 CUP's for Marlins ( about the same as the 444 Marlin pressures ).Lyman splits the data into 3 sections for Trapdoor Springfields ( about 17000 CUP's ),Marlin 1895's ( 28000 CUP's ) and Ruger No.1's at 40000 CUP's.
Since the 1895 uses the same basic action as the 444,356 Winchester and 375 Winchester ( the latter 2 operating up to 52000 CUP's in both Marlins and Winchester 94 "Big Bore's" in the Speer #13 and Lyman manuals ) it seems confusing to find such variations in load data between different manuals.I suspect case life would decrease as pressures are increased and the Marlin rifles may not tolerate a steady diet of 40000 to 50000 CUP's without stocks and fore ends loosening,as happened to a friend who fired hundreds of full power loads in his 444 Marlin.

Try to cross reference as much loading data as possible to allow you to proceed safely,watching for signs of excessive pressure,acceptable accuracy and tolerable recoil.

For what it's worth,the 2019 Sierra manual lists a max load of 51 grains of IMR 4198 for 2150 fps using their 300gr.HP in a Marlin 1895 ( also for the Ruger No.1 and No.3). Nosler's data also includes the modern 1895 as a "strong action" along with the 2 Ruger single shots using 51.5gr behind their 300gr.Ballistic Silvertip.Hodgdon's lever action loads start at 53.7 gr. and top out at 57.2 gr. with the 300gr. Sierra.The "modern" rifle data runs up the pressures to 50000 CUP's.

I can't comment on the Sierra 300gr HP but have used the Hornady 300 gr HP InterLock,as well as the 350 gr FP InterLock,and both provide good accuracy with IMR4198 and Reloder7.The InterLock design may prove to be a better design as velocities are increased beyond typical factory values if used on game.

It's a great cartridge to work with.