How to figure out pressure for Vihtavuori powders ......

tomhenry

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.........since they give no data on their website? And none of my manuals lists their powder..

Some manuals give pressures of various loads. For the 45 Colt in the 1873 Winchester max pressure is 14,000 psi.

But there are no such guidelines for Vihtavuori powders, and I'm wanting to use their N340 powder for 45 Colt 200 grain plated.

Their starting load for the 200 grain lead bullet is 10.9 grains for 1119 fps. Max load is 11.6 grains for 1194 fps.

I'm curious because they have a whole different category for cowboy shooting and don't even list the N340 powder. They list the N330 powder 8.0 grains at 876 fps. Max for N330 is 8.6 grains at 978 fps.

Is that because of the parameters for cowboy action shoots? Or is it because the 1873 action and the Colt SAA is too fragile for anything more?

BTW, both Berrys and Xtreme say their standard plated bullets are fine for any velocity up to 1200 fps.
 
tomhenry, what are you wanting to shot these in?

Let me offer a few things:

Standard SAAMI pressure max for ALL 45 Colt firearms is 14K psi.

(In many U.S. reloading guides a second set of 45 Colt load data is listed for stronger revolvers, like Rugers, T/C, etc, & these loads have no standardized max. pressure established for them by anybody.)

No idea whether Vihtavuori is using SAAMI (14K psi) or CIP (15,954 psi) standards in the manual you're looking at, but...

Sierra Reloading Guide v6.1 lists N340/11.7gr @ 1100mv in 45 Colt SAA & Replica models using their 200gr jacketed bullets as their max load so I'm sure it's within SAAMI specs. (FYI: N340/10.5gr = 950mv)

FWIW, I used QuickLoad v3.9 & it says N340/11.7gr is equal to a 63.2% full case.

.
 
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This is from Vihtavouri’s reloading data: “The listed maximum loads have been determined according to the respective CIP/SAAMI maximum pressure specification, whichever is lower.”
Their maximum pressure 45 Colt load data is the lower SAAMI standard of 14k.
 
same question, same answers

From V V 6th edition (1996?) Reloading Guide
Hdy 200 lswc, WLP primer, 1.594 col, Rem brass, 6 in barrel, CIP standards, N340

10.4 gns = 1080 fps, 10,000 psi (starting)
11.2 gns = 1156 fps, 13,300 psi (max)

If memory serves, V V eventually using our psi measuring standards and reduced some of their hotter pistol loads, which these do not appear to be (hotter).

This manual has 2 sections of 45 LC. One measured in CIP, one by CUP. Am not sure how this correlates, but the manual specifically states the CIP is done by European Standards at the case mouth, and not by SAAMI standards.
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If memory serves, V V later started using SAAMI standards.

All kind of irrelevant for the OP purposes, and am certainly not very knowledgeable on pressure testing methods.
 

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