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Old March 27, 2012, 07:38 PM   #13
BruceM
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Join Date: March 12, 2006
Location: SE Wisconsin
Posts: 285
Quote:
It might not care the shape of the meplat, but if in a .40 the shape of the meplat might have an effect on seating depth, which in turn changes your case volume, WHICH will GREATLY affect your pressures.
Roger that!

.40 S&W is a more extreme example of that but bullet setback can cause serious issues in Autoloader ammo. Why? Because the case volume is reduced and THAT causes higher and sometimes dangerous pressure. Now, starting low and working up with different bullets of the same weight will remove that problem except with powders like H110 but that does not change the fact that lesser case volume with the same powder charges equal higher pressure associated with that charge weight.

These type of questions usually revolve around questioning varying charge data for same round in different reference sources, trying to replicate a load without identical components or a combination of the same.

It is never a good idea to just duplicate somebody else's load. Back in the day, a common maximum load for .357 magnum with 158 gr SWC bullets was 15.0 grains of 2400. I shot hundreds and hundreds of these thru my 6 inch Python without issue and they were very accurate. One day at the range, a friend of mine with a new to him 5 inch M27 asked if he could try a few. The six shot string he fired produced an equally accurate result. However, he could not extract the empties using the ejector rod. They had to be tapped out with a wood dowel and rubber mallet at home. No permanent damage was done to his gun but they were obviously too stiff for that particular gun.

We obviously are not dealing with maximum loads here but the point remains that it is wise and safe handloading practice that all loads be developed in the gun you want to shoot them in, Rule #1 must be followed and no shortcuts taken.



Bruce

Last edited by BruceM; March 27, 2012 at 07:45 PM.
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