1:9 is pretty darn sketchy with 75gr A-Max.
I briefly had a 223 HH barrel, and 24.5gr Varget under a 75 A-Max shot just under 1" 5-shot group at 100 yards; I did not try it any further but the bullet holes in the target were round. That particular load wasn't for the HH barrel (which had a stupidly long freebore) but for another 223 I had at the time.
I was shooting in summer (close to 90F and 800' ASL elevation) so that probably helped.
Only way to know is to try them, but I wouldn't *expect* them to be stable. 75 HPBT, on the other hand, will be good to go.
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