So after having just loaded up a 100 count box of SMK 220's to 300 BLK subsonic of 2.089" COL and 11.2gn of AA11680, I got the bug to think about building a better mousetrap...
Couple of my primary considerations:
economics
accuracy
Here are the facts as I know them:
Price (as per Midway for general availability, shipping may vary);
SMK 220: $41.99/100 or ~$.42 ea
Hdy 225: $33.99/100 or ~.$34 ea
OAL;
SMK 220: 1.494"
Hdy 225: 1.580"
BC;
SMK 220: .629
Hdy 225: .670
Comment: Meplat consistency definitely goes to the Hornady rounds for measuring OAL
Using the same seating stem w/o changing any of the settings, using Remington .221 Fireball cases resized and trimmed to 1.355" the COL's were:
SMK 220: 2.089" as prescribed (
http://300aacblackout.com/)
Hdy 225: 2.144"
So far I'm seeing 3 factors coming to light, 20% saving, better ballistic coefficient and a steeper boat tail design and longer ogive, allowing for a COL closer to the lands. Barring benchrest testing (i.e. weight sorted brass, neck thickness and meplat uniforming, etc)...the economics alone are a clear winner.
I'll be doing some accuracy testing as soon as I get the chance but if someone gets to it before I do, please post your results!