Mark, I'm in wholehearted agreement with your assessment of the 223 AI. We've been shooting some precision rifle matches at a ranch in north central Ks.; one stage has 16"x18" steel plates from 300 out to 1400yds. I'd shot rifles in 6x47 Lapua & 284 Win up there, and had good results and fun with both. However, last time out, I took a little 223 AI that I'd built for myself to this match. Hey, it's run on a 'just-for-fun' basis, and the rifle was shooting Berger 90s (both LRBT & VLDs) really well, so why not? I'd gotten a good no-wind 100yd zero with several loads using bullets from H75AMax to the 90s, along with solid chrono data for each load. Ran the numbers on the point mass solver that Bryan Litz includes with his book on LR shooting, got print-outs done, and took off for the match.
There were no problems getting both hits on the plates out to 800, but I got blown off the right side with the 1st shot at 900, then sucked back off the left side with the 2nd. Got both hits at 1000, then got skunked at 1100 & 1200. Didn't see hits or miss impacts at 1300, nor on the 1st shot at 1400. I'd run out of internal scope elevation going up from the 1300yd target, and had to use reticle hashmarks to holdover for the 1400. Since I didn't see or hear anything out of that 1st shot at 1400, I held another 3MOA over for the 2nd one, and saw the impact - about 3 MOA above the target, which is set up on a hillside. When we went out to check the plates & paint over hits, we found one hit on both the 1300 & 1400yd plates. Litz's PMS shows the 90s going subsonic at around 1260yds, and I didn't know whether they'd remain stable or not past that. However, the impacts on the 1300 & 1400yd targets were uniformly round, so sign of any tipping or being unstable. PMS predicted a velocity of 1093fps at 1400; even with electronic muffs, and the wind coming from the targets towards the firing line, I didn't hear any impact at either 1300 or 1400.
But the come-ups from the PMS program were dead-on, and it's a lot of fun shooting this rifle - it's a M700 action in a McM A5 stock, 26" Krieger 1:7tw in sendero contour, Jewell HVR trigger, EGW 20 MOA sloped base, and a Vortex Viper PST 6-24x50 in TPS TSR rings. It's also got R-D DM BM, which uses AICS 10rd 223 mags. I loaded 80s for closer targets, from 200 out to 780yds, and used them to fireform. FF loads have been just as accurate as those put up in formed brass, so why not use the match format to get more FF'ing done?