ROUGH C.U.P. to PSI Conversion for Handloaders
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- Advanced Levergunner
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ROUGH C.U.P. to PSI Conversion for Handloaders
Thanks to GunnyMack, we are reminded of a way to develop a ROUGH estimate for converting C.U.P. (Copper Crusher) pressure listings to the more modern PSI (piezoelectronic) figures.
Handloading guides by Lee and Lyman, to this date, use predominantly C.U.P. data, which has not been of much use for working up loads with QuickLoad Ballistic Calculator software.
Here is the link that GunnyMack supplied via an online link to "NFG's" offering at MarlinOwners.com:
http://www.marlinowners.com/forum/reloa ... rmula.html
WARNING! Rough Estimates, Only!
PSI TO CUP
(PSI + 17902)/1.516
CUP TO PSI
-17902+(1.516XCUP)
Math Operation Order:
My Dear Aunt Sally – M D A S
Multiply, Divide THEN Add and Subrtact
Here is one listing from AmmoGuide that had a C.U.P. pressure rating. It was ran through QuickLoad using the same data. As per the warning, at least it gives you a ballpark figure to work with.
CARTRIDGE AND LOAD:
Sierra 170 gr. FP .30-30, H4198 22.5 gr., COAL 2.250" in a 24" barrel
AmmoGuide listing
1918 fps, 32,600 C.U.P. (= 31,520 PSI in conversion formula)
QuickLoad estimate
1981 fps, 31,749 PSI
My Excel application:
We need to be mindful, again, that:
* The conversion formula is an estimate
* QuickLoad data is all an estimate
A simple, bare bones Excel file (offered below) can be altered if you remove the "Protection" on it. It is not locked with a password. The cells are protected so that you only enter data in one of two cells so that the calculation will work.
If you use Excel and want this very simple tool, you can download either version through the following links:
PSI and CUP Converter.xls
(Excel 97-2003)
https://app.box.com/s/pneg62bse31bmh2jz8kaswitho8nmc8f
PSI and CUP Converter.xlsx
(Later versions Excel)
https://app.box.com/s/6tg49h0n6jttcfv3m9dei0dm45y6kpzx
Now the Lyman data, and that of others like Lee's handload book, will be much more useful for me.
Thanks again, GunnyMack.
Handloading guides by Lee and Lyman, to this date, use predominantly C.U.P. data, which has not been of much use for working up loads with QuickLoad Ballistic Calculator software.
Here is the link that GunnyMack supplied via an online link to "NFG's" offering at MarlinOwners.com:
http://www.marlinowners.com/forum/reloa ... rmula.html
WARNING! Rough Estimates, Only!
PSI TO CUP
(PSI + 17902)/1.516
CUP TO PSI
-17902+(1.516XCUP)
Math Operation Order:
My Dear Aunt Sally – M D A S
Multiply, Divide THEN Add and Subrtact
Here is one listing from AmmoGuide that had a C.U.P. pressure rating. It was ran through QuickLoad using the same data. As per the warning, at least it gives you a ballpark figure to work with.
CARTRIDGE AND LOAD:
Sierra 170 gr. FP .30-30, H4198 22.5 gr., COAL 2.250" in a 24" barrel
AmmoGuide listing
1918 fps, 32,600 C.U.P. (= 31,520 PSI in conversion formula)
QuickLoad estimate
1981 fps, 31,749 PSI
My Excel application:
We need to be mindful, again, that:
* The conversion formula is an estimate
* QuickLoad data is all an estimate
A simple, bare bones Excel file (offered below) can be altered if you remove the "Protection" on it. It is not locked with a password. The cells are protected so that you only enter data in one of two cells so that the calculation will work.
If you use Excel and want this very simple tool, you can download either version through the following links:
PSI and CUP Converter.xls
(Excel 97-2003)
https://app.box.com/s/pneg62bse31bmh2jz8kaswitho8nmc8f
PSI and CUP Converter.xlsx
(Later versions Excel)
https://app.box.com/s/6tg49h0n6jttcfv3m9dei0dm45y6kpzx
Now the Lyman data, and that of others like Lee's handload book, will be much more useful for me.
Thanks again, GunnyMack.
Last edited by JohndeFresno on Sat Dec 03, 2016 2:53 pm, edited 3 times in total.
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- Advanced Levergunner
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Re: ROUGH C.U.P. to PSI Conversion for Handloaders
There are a few loads with a few powders that defy logic and those are the ones to watch out for.
An example is Tite Group powder in the 9mm or .357 where just one grain more powder or a slight change in seating depth can DOUBLE chamber pressure. Care must be taken when data is not available
For the exact load used.
An example is Tite Group powder in the 9mm or .357 where just one grain more powder or a slight change in seating depth can DOUBLE chamber pressure. Care must be taken when data is not available
For the exact load used.
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- Advanced Levergunner
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Re: ROUGH C.U.P. to PSI Conversion for Handloaders
Thank you, Chuck.
Re: ROUGH C.U.P. to PSI Conversion for Handloaders
For some reason, Blue Dot is ok for .44 mag, and .357 mag, but not for .41 mag....At least so I've seem more than once, or twice...
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Second Amendment Foundation
Citizens Committee For The Right To Keep And Bear Arms
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Re: ROUGH C.U.P. to PSI Conversion for Handloaders
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- Advanced Levergunner
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Re: ROUGH C.U.P. to PSI Conversion for Handloaders
"Wholesalers carrying the Blue Dot powder brand from Alliant Powder should inform their retail customers of important safety information. ATK's Commercial Products Division has announced that Alliant Powder's Blue Dot should not be used in the .357 Magnum load when using 125-grain bullets (loads utilizing heavier bullets are acceptable for use with the powder).BlaineG wrote:For some reason, Blue Dot is ok for .44 mag, and .357 mag, but not for .41 mag....At least so I've seem more than once, or twice...
Blue Dot powder should not be used with any loadings in the .41 Magnum cartridge.
Use of Blue Dot powder in either of the above mentioned applications could result in a dangerously highpressure situation, the company announced."
I have the PDF saved and can put it online for your to download to show the source, if you like.
- GunnyMack
- Advanced Levergunner
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Re: ROUGH C.U.P. to PSI Conversion for Handloaders
JohnDe- happy to be of service! I found that with a quick google search before I left this morning to pheasant hunt. I got 1, my dog, Claro got 1. She saves me ammo!
I have older loading manuals that show Blue Dot for 41 mag. I'm thinking there was an old formulation of Blue Dot and WAS safe. And they changed it enough that it is no longer safe. Doesn't bother me, my Henry 41 really likes Lil'Gun!
How are the 270 loads working?
I have older loading manuals that show Blue Dot for 41 mag. I'm thinking there was an old formulation of Blue Dot and WAS safe. And they changed it enough that it is no longer safe. Doesn't bother me, my Henry 41 really likes Lil'Gun!
How are the 270 loads working?
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- Senior Levergunner
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Re: ROUGH C.U.P. to PSI Conversion for Handloaders
I need to dig through my notes but I thought PACO used Blue Dot in some of his 41 Mag loads? Years ago I was loading for my 401 Powermag using Blue Dot with no problem.JohndeFresno wrote:"Wholesalers carrying the Blue Dot powder brand from Alliant Powder should inform their retail customers of important safety information. ATK's Commercial Products Division has announced that Alliant Powder's Blue Dot should not be used in the .357 Magnum load when using 125-grain bullets (loads utilizing heavier bullets are acceptable for use with the powder).BlaineG wrote:For some reason, Blue Dot is ok for .44 mag, and .357 mag, but not for .41 mag....At least so I've seem more than once, or twice...
Blue Dot powder should not be used with any loadings in the .41 Magnum cartridge.
Use of Blue Dot powder in either of the above mentioned applications could result in a dangerously highpressure situation, the company announced."
I have the PDF saved and can put it online for your to download to show the source, if you like.
Mainehunter
Re: ROUGH C.U.P. to PSI Conversion for Handloaders
The 125gr blurb in .357 didn't apply to me...I was, and will be using 160s, and 180s..... I plink with .22
The Rotten Fruit Always Hits The Ground First
Proud Life Member Of:
NRA
Second Amendment Foundation
Citizens Committee For The Right To Keep And Bear Arms
DAV
Proud Life Member Of:
NRA
Second Amendment Foundation
Citizens Committee For The Right To Keep And Bear Arms
DAV
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- Advanced Levergunner
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- Joined: Fri Sep 07, 2007 1:52 pm
Re: ROUGH C.U.P. to PSI Conversion for Handloaders
Thank you, Harry. Saved to my archives. Very useful.
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Re: ROUGH C.U.P. to PSI Conversion for Handloaders
No offense to those who love Blue Dot, but a powder that touchy isn't one I'm going to ever use.....JohndeFresno wrote:"Wholesalers carrying the Blue Dot powder brand from Alliant Powder should inform their retail customers of important safety information. ATK's Commercial Products Division has announced that Alliant Powder's Blue Dot should not be used in the .357 Magnum load when using 125-grain bullets (loads utilizing heavier bullets are acceptable for use with the powder).BlaineG wrote:For some reason, Blue Dot is ok for .44 mag, and .357 mag, but not for .41 mag....At least so I've seem more than once, or twice...
Blue Dot powder should not be used with any loadings in the .41 Magnum cartridge.
Use of Blue Dot powder in either of the above mentioned applications could result in a dangerously highpressure situation, the company announced."
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Re: ROUGH C.U.P. to PSI Conversion for Handloaders
I used Blue Dot in the Ruger old model 41 mag in the '70s with 210 grain home cast semi-wad cutters without any incidents. Max loads from reloading manual.
hayabusa
hayabusa
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- Advanced Levergunner
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Re: ROUGH C.U.P. to PSI Conversion for Handloaders
I'll let you know, Gunny... Tied up at home these last 2-3 months with some 'mergencies. But I'm eager to use them great little babies that you sold me as soon as I can get out to the range!GunnyMack wrote:JohnDe- happy to be of service!...
How are the 270 loads working?