I have a 1:9 twist CZ 527 Varmint .223 with a 24 inch barrel and I use the CZs set trigger that breaks at less than 2 lbs to test loads off a F Class bipod and rear bag. The normal CZ trigger is 3.2 lbs without using the set feature and I can't get the same accuracy without using the set trigger.
By the way, I had to change the trigger on my Remington 700 in .22-250 with a 26 inch barrel to get anywhere close to its best accuracy. A Timney trigger reduced the average group sizes by almost 0.15 inches at 100 yards over the factory trigger. You might consider that if you are an accuracy freak like me.
The CZs best 69 grain group average at 100 yards is 0.378 inches for 9 measured groups with #1380 Sierra Match King bullets and 23.5 grains of H4895 powder at 2.260 OAL at around 2870 fps.
Deeper seating with 69 SMKs with the same powder load got into the 0.45 range and slower loads at 23.1 grains averaged just about under 0.510 . Faster loads with the 69 SMKs dropped off in accuracy and were getting into the Near Maximum range according to QuickLoad.
I've shot up to 75 grain bullets in the 1:9 twist with reasonable accuracy of just under 0.657 inches at 100 yards.
However, my rifle seems to really like 52 grain # 1410 HPBT SMKs and Berger # 22408 Flat base, and 53 grain # 1400 Flat Base SMKs better than anything else. It also shoots Nosler Ballistic Tip 40 grain bullets very accurately around 3450 to 3500 fps.
The Nosler BTs are like grenades when they hit prairie dogs.
Its top 25 hand loads are with 40 Noslers (2) and the 52 SMKs (6), 52 Bergers (6) & 53 grain SMKs (11). The combined loads average 0.265 over 95 measured groups.
Enjoy trying to find your rifles favorite loads. There are lots of great choices available for a 1:9 twist.