Saeco 540 grain 45-70 load...too much?

[Wheelweights]

Hi guys, first time poster.

I have recently got into casting my own. I was at a local show and scored a 540 grain saeco #020 mold for a very fair price. I was Excited, and came home / casted up a bunch /powder coated them / sized them to .458 to shoot from my Henry H015 45-70 single shot. From what henry says they are supposed to be at least as strong as the 1886.

Taking data from the trap door section of the cast bullet handbook for the saeco #020 540 grain(starting 28.5 grains of IMR 4198 or 31.5 max) I went with 29 grains of IMR 4198 over some dacron to keep the powder column against the primer. ( for reference the ruger no1 is starting 36 grains or max 40 grains @ 39,900 CUP)

I also had some 300 grain copper jacketed loads also at 29 grains. What surprised me was just how much more recoil the 540 grainer had. Of course i would expect it to have more as its much more mass to get moving, but it was at least 3 times more (or more lol).

So I started thinking with that much recoil how much pressure could be being generated? the primer looked flattened out some ( not really bad, but definitely some)

The ogive on this bullet is very wide up until the very end where it flats over, so in order to get the round into the chamber I had to seat it to 2.430 which was .020 off the lands. this gun seems to have a very short chamber? i think many of the available cast bullets have this wide ogive (like my Lee 405 grain) so most of the cast bullets would have to be seated like this to work. Is it possible that the chamber was designed for the steeper ogive on this modern factory ammo?

I was surprised that using trap door data seemed to produce this kind of power. could the seating depth have something to do with it? or should I just back off some more on the charge?

any other pointers greatly appreciated. thanks.

[Fitz]

I shot a 540 out of several 45-70 and use IMR-4198 but no darcon filler and 27 gr of powder I do paper patch but that hasn't much to change in the way of pressure and one of the rifles is a Lyman centennial ruger#1 with the heavy barrel and still the recoil is all I want but that bullet sure puts meat in the freezer deer and hoggs and with the single shots no crimp is needed.

[Wheelweights]

I shot a 540 out of several 45-70 and use IMR-4198 but no darcon filler and 27 gr of powder I do paper patch but that hasn't much to change in the way of pressure and one of the rifles is a Lyman centennial ruger#1 with the heavy barrel and still the recoil is all I want but that bullet sure puts meat in the freezer deer and hoggs and with the single shots no crimp is needed.

Thanks Fitz....do you recall what your OAL was with this bullet?

[Fitz]

I loaded them different for the different rifles but all were to where the rifling was just starting to engrave the bullet and could be unloaded without pulling the bullet , my pedersoli has almost no throat as the Ruger #1 has a decent one that allows the bullet to be seated much further out.

[Fitz]

I loaded them different for the different rifles but all were to where the rifling was just starting to engrave the bullet and could be unloaded without pulling the bullet , my pedersoli has almost no throat as the Ruger #1 has a decent one that allows the bullet to be seated much further out.

And the mould that I have is a Lyman not a saeco but they are close to each other

[mehavey]

Seated that deep (2.43" ?? !!), a parallel-design Lyman 535gr 457132/29gr/4198 is generating close to 38,000 psi
(definitely not trapdoor)

...some dacron to keep the powder column against the primer.

postscript: QL tells me the load above produces a totally full case of 4198. No airspace.
(?????)

[Bird]

Try shooting at some paper. 540 grains is a lot of bullet to stabilize in a barrel with a 1 in 20 twist. You may be better off with a 300 or 405 grain bullet. Try it and see if the bullets fly straight.

[mehavey]

The Pedersoli Sharps/45-70 is 1-18 twist, and serves the Lyman 457132 & Paul Jones Creedmoor (both 540-ish) well.
I think the biggest challenge is going to be the exceptionally-deep seating (if I read that 2.43" OAL correctly)

[Jeff Michel]

I also had some 300 grain copper jacketed loads also at 29 grains. What surprised me was just how much more recoil the 540 grainer had. Of course i would expect it to have more as its much more mass to get moving, but it was at least 3 times more (or more lol)

Newton's third law.......

[Wheelweights]

Seated that deep (2.43" ?? !!), a parallel-design Lyman 535gr 457132/29gr/4198 is generating close to 38,000 psi
(definitely not trapdoor)




postscript: QL tells me the load above produces a totally full case of 4198. No airspace.
(?????)

Interesting. I'm wondering where you got those pressure figures for the lyman 535gr?? the cast bullet handbook 4th edition (trapdoor section) shows 31.5 grains of IMR4198 producing 17,000 CUP with the lyman 457132 bullet?

similarly, the Saeco #020 is just slightly higher and states that 28.5 grains of IMR 4198 is a good starting charge for the trapdoor? - this load did not feel like trapdoor power! more like ruger no 1.

Yes seating depth of 2.43 which was .020 off the lands (picture for reference, black line was powder level) dacron was probably not needed, but wouldn't hurt anything either. I'm just in the habit of putting a small amount.

[dondiego]

Sure is seated deeper than I would seat it.

[Wheelweights]

Sure is seated deeper than I would seat it.

Agreed, but i had to in order for it to fit into the chamber. the 405gr lee cast have the same ogive and need the same seating.

[FLINTNFIRE]

Might like a slimmer profile nose to seat out further , that is pretty deep , I can see more pressure and more recoil seating that deep with a big chunk of lead , but to each their own .

I find my 84 trapdoor will take a fatter profile bullet and the sharps I own will not .

[Wheelweights]

Might like a slimmer profile nose to seat out further , that is pretty deep , I can see more pressure and more recoil seating that deep with a big chunk of lead , but to each their own .

I find my 84 trapdoor will take a fatter profile bullet and the sharps I own will not .

Yeah, throat depth seems to be all over the place on different 45-70 chambers.

does anyone know if I could substantially drop the powder charge and still be safe? like 20-25 grains?

I love big heavy slow bullets. tons of fun smacking steel.

[mehavey]

Quickload tells me:
Lyman 457132 (535gr)/IMR4198/22.0gr/2.43" replicates the
18,000psi trapdoor load/pressure/velocity in the Lyman Manual
-- but at your (much) deeper seating depth.

[Wheelweights]

Quickload tells me:
Lyman 457132 (535gr)/IMR4198/22.0gr/2.43" replicates the
18,000psi trapdoor load/pressure/velocity in the Lyman Manual
-- but at your (much) deeper seating depth.

Thanks for this info. i need to sub to Quickload

[mehavey]

QuickLoad is 'bought' software: https://www.neconos.com/quickload-ba...tion-software/
If/when you do get it, it's like any assisting capability to generate information useful to handloaders.

One should never use it without both a companion chronograph, and a whole stack of reference material for comparison & backup.

It's theoretical physics & chemistry combined, requiring experimental test & adjustment.
But it's also reeeeeally good at what it does, and gives you options that can be found nowhere else.






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BTW: Max SAAMI pressure for the 45-70 is unique in that for this cartridge, Max CUP = Max PSI