I have just started loading .40's, though I have been reloading 9's and .45's for decades. I keep seeing references that lead me to believe the .40 is a ticking thermo-nuclear device waiting to kaboom
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All this didn't sound just right to me, so I did a little research. According to my Lyman 48th Edition, the high end .40's run about 23,000 CUP. That's certainly more than the .45 or .38 Special, but the lowly 9mm high end loads run almost ten thousand units higher.
Lyman recommends Bullseye as a go-to powder for both if my memory serves. While there is certainly the potential for an overload with fast burning powder, the same potential certainly exists in the rest of the cartridges listed. Does the .40 have a bad rep due to folks trying to make a 10mm out of it for competition purposes?

All this didn't sound just right to me, so I did a little research. According to my Lyman 48th Edition, the high end .40's run about 23,000 CUP. That's certainly more than the .45 or .38 Special, but the lowly 9mm high end loads run almost ten thousand units higher.

