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Please, provide your recomendations for referances and/or software for predicting wildcat performance, and assisting with load developement. As I mentioned I am new at this and can use all the supporting materials and aids I can secure.

I know that the cartridge will physically function and is the largest that can ( without the move to a custom extruded case ), but I need to refine my performance predictions. Also, if you can help with these predictions: I will be using BTB bullets. The barrel length will be 20". The case capacity is 40 grains of water for the case cut to the seating depth and 50 grains to the mouth. The current cases are somewhat hourglass shaped until fireforming or dies are available, final capacity should be about 42 to 44 grains. Since I would rather be happy about the extra powder space than disapointed I am working from the 40 grains.

Thanks,
Fireplug
 

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Fireplug,

The first reference I'd look at would be Powley's Computer.......used to be a set of charts and graphs before there were computers, but its now available on a CD for your computer.

Lobo in NM
 

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Discussion Starter #3
El Lobo,

Do you have a source for the Powley's Computer CD? Knowing that I should have it, I have done search after search on several engines and Have been unable to find a source.

Thanks,
Fireplug
 

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Fireplug,

I've seen it advertized in "American Rifleman" and "Handloader" but not in every issue.  Let me look through a few back issues.  I'll also post on the Marlin Talk website, and the CBA listserv.  Someone surely can give us a lead.

Lobo in NM
 

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Powley's computer is a card board slide rule.
I like mine but the more modern computer types will like loads from a disk a little better.
Loads from a disk is for IMR powders, as is the Powley. You can download a sample from the loads from a disk web site.
Go to sixgunner.com and look at M.L. McPherson's page. He helped write a program that is a little more modern and has a more universal application.

You can get by very well with a Powley computer and the RCBS Load program. The RCBS load has a cartridge designer that is easy to use and gives water capacity. This is helpful for comparing neck angles/lengths and case body taper.
 

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Hi, Fireplug:
    Your cartridge is off scale on my old cardboard Powley Computer. It's not designed for a Powder weight / Bullet Weight in the 1 / 10 ratio range.  I did some very rough figuring and got 32 grains of 4198 for a velocity of 1760 fps with a 335 gr. bullet.  This is not a recommended load!

   Contract Neco at http://www.neconos.com/ They have the McPherson (QuickLoad) program and one of the guys got a load over the phone from them. It's a much newer and versatile program than Powley.

Bye
Jack



<!--EDIT|Jack Monteith|April 25 2002,11:36-->
 

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William,

I have a copy of Powley's original "computer".  To say it's a cardboard slide rule does it an injustice.  It is a dozen inter-related ballistic computational charts derived from a study of the math and physics of the ballistic sciences.  This "cardboard slide rule" allows you to do both internal and external ballistics.  Additionally, all of these capabilities are now available on a CD for computer use.

Lobo in NM
 

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Discussion Starter #9
Thank you all. The knowledge base and helpfulness of those on this forum is remarkable. I will follow up on these leads and give an update on what I learn plus my research for the rifle, reamer(s) and dies at the NRA show.

Fireplug
 

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Discussion Starter #10
Thank you all. The knowledge base and helpfulness of those on this forum is remarkable. I will follow up on these leads and give an update on what I learn plus my research for the rifle, reamer(s) and dies at the NRA show.

Fireplug
 

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El Lobo

No injustice meant to Homer Powley.
In the '50's and '60's when I was growing up and reading the gun press with wide eyes the Powley Computer for Handloaders was commonly refferd to as "Powleys slide rule for handloaders."
Robert Hutton in the 4th edition of the Handloaders Digest (1962?) wrote an article on the best way to pick powders, he says on page 46:
"The Powley Computer for Handloaders, a slide rule designed and produced by Homer S. Powley, now engineering scientist for Colt, gives the correct basic load with Du Pont powders, in cartridges whose capacity range is between some 22's and the 460 Weatherby Magnum."
Dean Grennel in the 1960's American Reloaders Acossiation Bulletin (ARAB) often refferd to it as: "Homers Cardboard Univac."
Growing up on the writings of Homer Powley, Robert Hutton, Ed Yard, W.C. Davies, Phil Sharpe, P.O. Ackley and even Wiley Clapp, fostered a strong interest in mathmatics, internal ballistics and guns in general for me.
W.C. Davies has published the math for Powleys computer in several venues and with todays home computers and powerful spredsheets you can, with some difficulty, produce your own version of Loads From A Disk! Davies also published an interesting article in the Rifleman on the possibilities of the pocket calculator for handloaders.
I am thankful for all of these pioneers who led the way with slide rules, pencil and paper.
 

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Hi, Guys & any lurking Ladies:
   An interesting lady has the Powley math and a worked through example on her website.
http://www.aeroballisticsonline.com/
Scroll down the left side box and click on "IMR Powders".

   A question.  Did Bob Forker design the Powley Computer?  He used  Powley's equations of course.

  I haven't seen a cardboard external ballistics computer, although IIRC Speer had one.  I used the Ingalls' tables in Hatcher's Notebook for external ballistics calculations.

Bye
Jack
 

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Jack

An interesting web site. It will take some looking to get through all of it.
I like the bullet spin and rifling page.

I understand that Homer Powley did the math and made the computer. The latter pressure calculator that works with the basic computer was also a Powley creation, according to Robert Hutton. It was originaly marketed through the Hutton Rifle Ranch.

I think Bob Forker worked for Hutton. Not sure of this of course. I think Forker has a lot offer but that he is held back by his magazine.
 
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