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Ahhh...the venerable AI debate.

I often suspect people forget how the AI concept came about, and truly how little it delivers these days (performance wise) over the standard chamberings.

"Ackley Improved" came about as a result of limited powders in those days, where by and large the majority of powders were some derivitive of surplus military powder sold to the shooting community. Since there were often wide gaps in performance between the powders, the AI modification reaped huge benefits by allowing additional slower burning powders to be used and taking advantage of the gases in conjuction with the shoulder angle change. This is not often true these days (or at least worth the trade offs).

There are exceptions to the rule. Even today, many of the straight walled cartridges will benefit (AI Hornet comes to mind immediately), but sadly, with advent of newer modern powders with wide ranging burn rates, AI is not really benefitial (IMHO) for most bottle necked cartridges. There's just not enough performance gain to warrant the increased throat erosion that occurs (largely due to faster burning, modern powders). In addition to this, AI can serious impede reliability in feeding. Many times the sharp shoulder angle is problematic at best, and sheer hell in some actions at the other end of the spectrum.

BTW, these are not just my feelings on it, these were actually Ackley's as well, years after the AI craze went overboard. An older and close friend of mine, showed me the letters that he and Ackley exchanged over the years on the subject, and it was enlightening to say the least...

Don't get me wrong, I'm not knocking "doing it" (the joy of this passion/hobby is often times doing things "just because I can"), I'm just throwing out some food for thought. (I wish I had a dime for every crack pot, one off thing I did...

)

YMMV...

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MarinePMI

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