45-70; Max case capacity is 8gr under recommended starting load???

H Wally

H Wally

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Well, this is interesting. I am working on my first loads for the 45-70. The data I have found all suggests starting loads using more powder than can fit in the case with the bullet, leading to excessive compression, difficulty in seating the bullet, squishing of the ballistic tip and a little bit of case warping (I suspect the case warping is related to excessive crimp, so possibly irrelevant). Short story is that starting load suggested in 56.5 gr and 58 gr. Max case capacity with no powder compression and bullet seated to proper depth is 49 gr.


Here's the breakdown of the details:

Bullets are Hornady FTX 325gr, Cases are FC and RP. Powder is IMR 3031

Hogdon data doesn't have any info for 325 gr, but has for 300gr and 350gr.

Data for 300gr/IMR 3031 is:
Start 58gr; Max 64

Data for 350gr/IMR 3031 is:
Start 56.5gr; Max 60 gr

Sourced from here:
http://data.hodgdon.com/cartridge_load.asp - Rifle cartridges, 45-70 lever actions.


I thought since I'm using a heavier bullet than the 300gr and lighter than the 350, and it's a dead even difference, I'd split the data for a 57gr load of IMR 3031. Sadly, that load only leaves .264 of an inch to seat the bullet before starting compression. In order to seat to proper depth I need .525 minimum. As a result, at starting load I'm already compressing my powder by 0.261. A drop tube and tapping the case does little to nothing to better seat the powder and gain space.

Turns out max uncompressed capacity with the bullet is 49gr of IMR 3031.

So guys, what the heck is going on??????? Data for 325gr bullets isn't that common and most other data I've found mimics hogdon's data, so how is it that all my cases somehow can't even properly fit the published starting loads????



EDIT
Also getting creased cases from crimping, have tried adjusting and backing off crimp but still getting creasing.
 
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My guess is that the data you are using is for a different bullet shape that has a greater portion of the bullet mass outside the case. Toss in some differences in case capacity between manufacturers that will explain the difference.

Drop your max load to 49 gr and see how it shoots. Maybe that's "the" load for that bullet.
 
jethunter said:
My guess is that the data you are using is for a different bullet shape that has a greater portion of the bullet mass outside the case. Toss in some differences in case capacity between manufacturers that will explain the difference.

Drop your max load to 49 gr and see how it shoots. Maybe that's "the" load for that bullet.
Click to expand...

This.

When you were on the Hodgdon Reloading site, the loads included the type of bullet and its loaded Over All Length (OAL). I see a range betwwen 2.525" and 2.540", meaning that about 0.425" of the bullet is outside the case. By the looks of this bullet, that would only be the case if it was seated out to the top crimp groove (i.e. deep in the case). That's a very long bullet for its weight (1.100") more than 1/4" longer than most of its same weight.

45015.jpg


All to say that you might not be able to fit a max load of IMR-3031 into the case if you seat this long bullet at the published OAL.
 
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This might help with your crimping problem . . .

1) Seat the bullet so the case mouth comes even with the front edge of the cannelure,
2) Crimp each cartridge as a separate step from seating,
3) Back off the seating stem, unlock the die, and back it off several turns,
4) Place a loaded round in the shell holder and run the ram to the top of its travel,
5) Turn in the seating die until you feel contact with the cartridge, then turn in a bit more, say a quarter turn,
6) If you are using just finger tip pressure, you can turn the die in till refusal, which isn't a bad way to get uniform results,
7) Inspect the crimped cartridge and apply more crimp as required,
8) Crimp each cartridge individually in this manner without locking in the seating die.

If case capacity is a problem, you could rechamber to .458 Winchester, and gain nearly half an inch of case length.
 
What brand of dies?
Sounds like some crimping is taking place before the bullet is fully seated, which causes wrinkles.
Depending on the dies you might need to back it out till no crimping is happening, then adjust in till it removes the case flare.
 
Thanks guys! I'm reloading for a friend's guide gun, so it makes it difficult to not be able to make up dummy rounds to cycle through and get things figured out that way.

jethunter said:
My guess is that the data you are using is for a different bullet shape that has a greater portion of the bullet mass outside the case. Toss in some differences in case capacity between manufacturers that will explain the difference.

Drop your max load to 49 gr and see how it shoots. Maybe that's "the" load for that bullet.
Click to expand...

Thanks! I've never really encountered this with my milsurps so it was bothering me a bit.


Andy said:
This.

When you were on the Hodgdon Reloading site, the loads included the type of bullet and its loaded Over All Length (OAL). I see a range betwwen 2.525" and 2.540", meaning that about 0.425" of the bullet is outside the case. By the looks of this bullet, that would only be the case if it was seated out to the bottom crimp groove. That's a very long bullet for its weigth (1.100") more than 1/4" longer than most of its same weigth.

45015.jpg


All to say that you might not be able to fit a max load of IMR-3031 into the case if you seat the bullet deeper than the published OAL suggests.
Click to expand...

Good to know - not having reloaded 45-70 before I wasn't sure if this bullet was standard fare or something out of the ordinary for size.

Boomer said:
This might help with your crimping problem . . .

1) Seat the bullet so the case mouth comes even with the front edge of the cannelure,
2) Crimp each cartridge as a separate step from seating,
3) Back off the seating stem, unlock the die, and back it off several turns,
4) Place a loaded round in the shell holder and run the ram to the top of its travel,
5) Turn in the seating die until you feel contact with the cartridge, then turn in a bit more, say a quarter turn,
6) If you are using just finger tip pressure, you can turn the die in till refusal, which isn't a bad way to get uniform results,
7) Inspect the crimped cartridge and apply more crimp as required,
8) Crimp each cartridge individually in this manner without locking in the seating die.

If case capacity is a problem, you could rechamber to .458 Winchester, and gain nearly half an inch of case length.
Click to expand...

Thanks! I tried something similar last night, but it was rather late so I probably wasn't doing it exactly right.

hometownhero said:
Hornady data for you. Note the trim length they suggest.
Click to expand...

Thanks! Great to get some hard data instead of filtering it online - makes me a little more comfortable :p
 
As stated, the FTX bullets are quite a bit longer. In order to get them to 2.525" you need a shorter case like the Leverevolution ammunition. Compare the bullets to a 300 jhp or 350 rn/fn and you will see the difference. Now to set you seating die you would sit an empty case in the shellholder, run the ram up and turn the die down until it contacts the case. Back it out a quarter turn and begin seating a bullet, adjusting seating depth to what you want. Then back the seating plug out a turn, loosen the die and tighten it 1/4 turn at a time, running the ram up to get the crimp you want. When you have it set, lock the die down and tighten the seating plug snug on the bullet. Consistent roll crimping requires consistent trim lengths. A couple thou can make the difference between no crimp and a bulged case.
 
supernova said:
As stated, the FTX bullets are quite a bit longer. In order to get them to 2.525" you need a shorter case like the Leverevolution ammunition. Compare the bullets to a 300 jhp or 350 rn/fn and you will see the difference. Now to set you seating die you would sit an empty case in the shellholder, run the ram up and turn the die down until it contacts the case. Back it out a quarter turn and begin seating a bullet, adjusting seating depth to what you want. Then back the seating plug out a turn, loosen the die and tighten it 1/4 turn at a time, running the ram up to get the crimp you want. When you have it set, lock the die down and tighten the seating plug snug on the bullet. Consistent roll crimping requires consistent trim lengths. A couple thou can make the difference between no crimp and a bulged case.
Click to expand...

While consistent case length is desirable, it can prove elusive, and regardless of how anal you are, there is always going to be a certain case length tolerance you'll have to live with. While the match shooter might spend the time to keep this tolerance to a minimum, the guy who loads for a hunting rifle doesn't need to. Provided that each cartridge is crimped individually, case to case length variations are irrelevant to consistent crimping, but don't expect to lock down the seating die after finding a good crimp for cartridge "A", and expect all the subsequent cartridges to crimp exactly the same. Chances are they won't, not even from new. But if you keep the seating die loose, and turn it down so that you manually set the crimp for each individual cartridge, the results will be nice consistent crimps. As for the time it takes, it takes only a second longer than locking the seating die down, running the rounds through it, and getting inconsistent results. A better option for some is to purchase a Lee factory crimp die, if they make one the cartridge you're loading.

Case length is critical to reliable cycling through your action if you're using the combination of a long bullet and a cannelure near the bullet's base, and it is critical to safety if case stretch allows the case mouth to enter the lead of the chamber where it has no expansion room to release the bullet. Straight wall tapered cases like the .45/70, .450 Marlin, and the .458 don't lengthen from firing. Trimming therefore is only necessary to clean up small case mouth fractures, or to shorten the case enough to allow the cycling of long for caliber bullets in your rifle.
 
"...The data I have found all suggests..." I'd suggest you look again. Something you've done isn't right. 70 grains of BP fits with room to spare and BP is much coarser than any smokeless powder.
"...450 Marlin loads..." You can use .45-70 data. The Marlin is just a rimless case.
 
sunray said:
"You can use .45-70 data. The Marlin is just a rimless case.
Click to expand...

Once again you are trying real hard to injure someone aren't you? The 450 Marlin case has 5-10% LESS case capacity (dependent on brand) than the 45-70 Trying to load them equally may well ruin a good rifle.

As measured by Brian Pierce

1-.450 Marlin Brass/73.5 grains of water(2.7 grains less than Remington 45-70 Brass!!!)
2-.45-70 Remington Brass/76.2 grains of water(1.3 grains less than Starline Brass)
3-.45-70 Starline Brass/77.5 grains of water(2.8 grains less than Winchester Brass)
4-.45-70 Winchester Brass/80.3 grains of water.(4.1 grains "More" than Remington Brass.)
 
That is certainly a good way to do it especially if you trim before sizing. FL sizing can leave perfectly trimmed brass a couple thou out in length. A good reliable method I use is a Lee trimmer after sizing which leaves variances in trim length of less than 0.001and nice identical crimps. All great ways to skin the cat and I'll be adding your method to my notes.

Boomer said:
While consistent case length is desirable, it can prove elusive, and regardless of how anal you are, there is always going to be a certain case length tolerance you'll have to live with. While the match shooter might spend the time to keep this tolerance to a minimum, the guy who loads for a hunting rifle doesn't need to. Provided that each cartridge is crimped individually, case to case length variations are irrelevant to consistent crimping, but don't expect to lock down the seating die after finding a good crimp for cartridge "A", and expect all the subsequent cartridges to crimp exactly the same. Chances are they won't, not even from new. But if you keep the seating die loose, and turn it down so that you manually set the crimp for each individual cartridge, the results will be nice consistent crimps. As for the time it takes, it takes only a second longer than locking the seating die down, running the rounds through it, and getting inconsistent results. A better option for some is to purchase a Lee factory crimp die, if they make one the cartridge you're loading.

Case length is critical to reliable cycling through your action if you're using the combination of a long bullet and a cannelure near the bullet's base, and it is critical to safety if case stretch allows the case mouth to enter the lead of the chamber where it has no expansion room to release the bullet. Straight wall tapered cases like the .45/70, .450 Marlin, and the .458 don't lengthen from firing. Trimming therefore is only necessary to clean up small case mouth fractures, or to shorten the case enough to allow the cycling of long for caliber bullets in your rifle.
Click to expand...
 
iload my 45 70 marlin 51 gr 3031 case lenght is 1/8 shorter when using ftx bullets or you may have feed problem.also for crimping i cut 1/8 " off off bottom of crimp die to allow for the shorter case. hornday cases are 125 th shorter than normal brass.Be cautious using 4198 in older design rifles I only use it in ruger #1
 
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