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Quickload check for 45/70
Posted: Mon Sep 01, 2014 11:13 am
by GRSporth1
Could someone with Quickload do a check on a 45/70 load I have come across? I am suspicious of it and certainly don't want to try it without another cross reference:
45/70 case, 405gr RNFP lead bullet, LR primer, 16-19gr Viht N350 powder.
Other reloading data suggests this is pushing it on pressure - It sounds like quite a lot of (relatively) fast powder for the case, even for stronger actions.
Can anyone help? Many thanks.
Re: Quickload check for 45/70
Posted: Mon Sep 01, 2014 1:24 pm
by dromia
QL suggests a 16 gn load of N350 to generate a chamber pressure of 20410psi against a maximum (SAAMI) pressure of 28000psi based on an coal of 2.550" with a lyman 405, LYM LFN 457193.
19 gns comes out at 27896 psi which is just within the pmax.
What does the Vihtavuori data suggest?
Re: Quickload check for 45/70
Posted: Mon Sep 01, 2014 5:07 pm
by GRSporth1
Dromia, many thanks.
I've had good luck in the past duplicating 45/60 ballistics in a 45/70 using 15g of True Blue. I have wondered for some time about trying to step up to see if I could get up to genuine 45/70 ballistics without resorting to the usual case full of slow powder.
This N350 load came out of a load of internet searches - not always the most reliable of sources! - which led to some calculations of my own based on Lyman and Viht's data on similar cartridges & bullet weights and applying basic burn rate equations. Viht wouldn't commit themselves, they only recommended slower powders like N120/130.
Glad to see I was not far out - in fact I was coming up with numbers between 28-33kpsi.
BTW - in case anyone else thinks this is all a good idea, go slowly when working up this type of load, some manuals are more cautious than others and not all 45/70s are created equal. I use a modern Winchester 1886 to do it - this is a much stronger gun than any of the Springfields, Sharps etc.. (even the modern repros).