need some help with pressure units-CUP.

[Axis II]

So I was going through my hornady, hodgdon and lyman manuals for 45-70 lever actions data to load 300gr HP for my cva elite stalker single shot. I emailed CVA about reloading for it and they said use lever action data. in lyman it says do not exceed 28,000 CUP. Hodgdon shows every starting load for every lyman listed powder and more all over 28,000 for a start load and Hornady is also higher in some start loads than 28,000 CUP. Lyman shows IMR 4198 at 36gr and Hodgdon shows a start of 53.7gr. that's a huge jump in start loads. that CUP is 33,100 and topped out at 39,100. iMR 3031 is also way off per lyman 49th.

whats the right thing here? Hodgdon, lyman, hornady?

 

[Orcon]

Probably all...or neither. They might as well tell you to not exceed 35000 Unicorn Farts, CUP is about as worthless a system of measurement to Joe Reloader. You could just play it safe and go with the lowest charge listed.

 

[Reloadron]

The Lyman 49th gives you three sets of load data. The light loads for the 1873 Springfield, the medium loads for the 1886 Winchester & 1895 Marlin and the pretty heavy stout loads for the Ruger No.1 and No. 3. Keep in mind the pressures published in the Lyman Manual were for their test configuration using their Universal Receiver. You really don't want to start trying to chase chamber pressures and I am surprised CVA even tossed a chamber pressure number at you. Anyway, not exceeding 28,000 CUP puts you in about the middle or medium 45-70 Government load data, the loads for 1886 Winchester and 1895 Marlin.

I have an old (1999) Hodgdon load data pamplet sitting here which calls out H4198 (Not IMR 4198) Trapdoor Load 300 grain HP bullet 55.0 grains of H4198 yielding 27,600 CUP. I have no clue how their loads were tested.

Overall if I were you I would just work with 45-70 Government data aimed at Trapdoor and or the lever guns or in other words the light to medium loads. I can't see trying to chase pressure data. Using IMR 3031 and a 300 grain HP bullet I would keep my loads around 45 to 55 grains of powder which is a large spread. That keeps you mid and upper light to medium loads or Trapdoor to Lever Gun.

whats the right thing here? Hodgdon, lyman, hornady?

I really doubt there is a "right thing" I can tell you that you will get the best results with the full cases verse little powder in a big case like the 45-70 Government so look for loads that fill the cases.

Ron

 

[ants]

I am surprised CVA even tossed a chamber pressure number at you.

They didn't toss out a number. CVA said lever action data.


Ohihunter pulled the 28,000 from the Lyman data. Not CVA.


Reloadron is right about the Lyman data, it's divided into 3 sections.
Use the Lever Action section as CVA instructed.


I think Ohihunter slightly misunderstands the Lyman book.
They are not telling you to stay under 28,000 CUP.
They are just mentioning that their Lever Action data is less than 28,000 CUP.
That is the pressure cutoff they decided for themselves as safe for lever action.

Use the Lyman data for 1886 Win and 1895 Marlin, that's the right data for you. Ignore the others.

 

[Axis II]

They didn't toss out a number. CVA said lever action data.


Ohihunter pulled the 28,000 from the Lyman data. Not CVA.


Reloadron is right about the Lyman data, it's divided into 3 sections.
Use the Lever Action section as CVA instructed.


I think Ohihunter slightly misunderstands the Lyman book.
They are not telling you to stay under 28,000 CUP.
They are just mentioning that their Lever Action data is less than 28,000 CUP.

Use the Lyman data for 1886 Win and 1895 Marlin, that's the right data for you. Ignore the others.

Yep you are right. I emailed them and asked what their rifle fell under for reloading (trapdoor, levergun and modern rifle) and he said lever gun.

I might have misunderstood it. When reading the paragraphs about the cartridge heritage and what not it mentioned about 3-4 sentences from the bottom about don't go over 28,000. I've already made about 20 trips downstairs and the books down there and I'm too lazy for trip 21 so I will take your word.

 

[Reloadron]

So I was going through my hornady, hodgdon and lyman manuals for 45-70 lever actions data to load 300gr HP for my cva elite stalker single shot. I emailed CVA about reloading for it and they said use lever action data. in lyman it says do not exceed 28,000 CUP.

Sorry, my bad read on that. I would just work from lever action data and thanks ants for pointing things out. I really misread the heck out of that.

Ron

 

[ants]

All good. Hunter got the right advice from all of us. Can't beat that!