Originally Posted by 406_SBC
Originally Posted by greydog
The REAL difference is on the order of ten to fifteen fps; tops. Keep in mind, the only valid comparison is to load the two cartridges to the same pressure in the same barrel. This does not mean the same pressure in a similar barrel or a similar pressure using different components in a longer barrel. It also doesn't mean comparing a maximum load in the AI to a factory load in the standard chambering. These are all favorite techniques of AI advocates. GD
Love to hear how you know this to be true. Can you please share the equipment you have used to verify this information? Thanks.


I know this to be true mostly because of an accumulation of 35 years of experience as a gunsmith and considerably more than that as a shooter and experimenter. I have chambered "improved" cartridges from the K-Hornet to the 375H&H AI (and this does include the 223 AI) and have chronographed most of them. When tests are run to compare standard and AI'd chambers, the real surprise is often what the parent case will do when loaded to pressures which are accepted as usable by the AI advocates.
There are some improved cartridges which can offer a significant increase over the standard case but the 223 isn't one of them; no matter how much we might wish it to be so. GD