[woody]

When using Winload to calculate CUP, I get a higher number when calculating for a 18.5" barrel than I do when calculculating for a 26" barrel. I would think that the results would be the exact opposite of this. Can anyone explain how this works?
Thanks,
Chris

 

[Jack Monteith]

Hi, Woody:
 Winload has some limitations, and I may have time to go into detail tommorrow. Meanwhile, don't depend on it for reliable data with low pressure cartridges .45-70), and work up loads for high pressure cartridges (.30-06).

 If you want to play with Homer Powley's original math, goto:
http://hometown.aol.com/slavetiger/
Then on the left side, under Interior Ballistics, click on "IMR Powders".

Bye
Jack

   

 

[Jack Monteith]

Hi, Woody:
  Since velocity increases with barrel length, all else being equal, if you get equal velocities with barrels of different lengths, the shorter barrel must be operating under higher pressure. It has to accelerate the bullet in less distance, and that requires more pressure.

  I hadn't played with Winload for a year. The only real problem it has is that you can't switch powders and see what happens. This is a real problem with the .35 Remington and a 200 grain bullet, since Winload recommends HiVel #2, which was discontinued in 1964.

  The Quickload program from NECO is much more advanced and flexible. Only problem is, it's &#36150. You can get a demo from:
http://www.neconos.com/
  It's a big step up from Homer Powley's work, but please remember that Mr. Powley did this over 30 years ago, and computers weren't on every desk.

Bye
Jack