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Discussion Starter · #1 ·
i shot some 45 winchester magnum using the 250 grain barnes bullets and am wondering about the possible overpressure signs. of course i look at the primer and i know to look for the flattening. i have seen primer flattening on several factory loads for other rounds like 44 magnum. these 45 win mag are real close to the same as 44 magnum. for my test loading and buildup i have a contender to use as the test gun, its tough and can handle overpressure i am sure very well. so the question is, whats the best i can do with my limitations to be sure to not have way to high a pressure but still make the most of the loads? other than primer flattening what should i look for? i did chronograph some and the velocity is what i want. let me know your thoughts and thanks!
 

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i like to measure case head expansion... i like to take a factory bullet that i have a good idea on the pressure, then use the same case to reload with and compare the case head expansion for my reload recipe... its not perfect, but imo it is a pretty good method to make sure you are not over pressure compared to a known factory load...
 

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The Lyman Pistol & Handgun manual as well at #47 have loads for the 45 win mag. The older Lyman manuals tend to push the limits on their maximum loads. I've loaded plenty 260gr gas checked cast bullets up into the 1500fps range following the Lyman recipe's using Blue Dot. Very accurate and clean burning. I also shoot a 14" Contender and a Wildey in 45 win mag. I love loading and shooting the 45 win mag. They will flatten primers and even flow into the firing pin hole. Never exceed the Lyman recipes.

If you have a chronograph then you can compare velocities with those published for a given load. Although velocities can't indicate high pressures, you can at least compare yours with Lyman's, provided all component's are equal.
 

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Discussion Starter · #4 ·
I am really glad that i bought a contender in 45 win mag for test and development of loads. I also really like the blue dot. Getting load data for barnes all copper bullets was a challenge. Someone here ran the idea thru some program and i am using it. I feel that i have found the max safe accurate load using aa7. I am going to back it down just a bit and call it good. Barnes bullets are nice but expensive especially when just shooting thru a chronograph.
 

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If you are seeing signs of overpressure you are already exceeding safe pressure levels. I would also expect any loads worked up in a Contender barrel to show higher pressure signs than in a shorter barreled semi.
 

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Discussion Starter · #6 · (Edited)
the trouble with overpressure signs is that having loaded many many rounds of 44 magnum to what is publiched as safe loads they have many many times shown all the wayyy flattened primers and cases overpressured. and those were within safe perimeters from several sources and in several different firearms. i think that safe perimeters for magnum firearms expect some signs of high pressure, but not necessarily overpressure,,,, heck i have seen flattened primers from factory loads for magnum handguns. whats up with that?
 

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It's my feeling that a rimmed handgun cartridge shot with the required spacing between the cylinder and the frame induces a flattening effect when fired in a revolver. This would not be present in a closed breech gun like a Contender or the semi auto. The breech face is already hard up against the cartridge. I certainly could be wrong. I've seen this too firing book loads in my .41 magnum.
 

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Enlarged primer pockets, and can have traces of soot. Increased head case expansion. Difficult to extract. Ejector marks on the head of the brass.
 
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