I could shoot em all in one group, and had considered that, but was afraid that I'd shoot up and lose my aiming point (tiny bullseye). Without the aiming point, I'd lose what little precision that I have. But...since I'm not really hitting the bullseye, but just above it by an inch or so, then I guess it won't matter. Yep, I'll shoot all 20 at once. I've found that accuracy is best in the first 15 rounds, so I'll clean every 10 and fire one fouler, though this rifle doesn't seem to change POI when clean. I hadn't known that before.
Shmellba, my limitations of old shooter and sporter weight barrel might make this comparison meaningless, but I will continue with this. It interests me, and with the weather being so hot, I don't feel like hunting. And most of us are just hunters and shooters like me, and with sporter weight barrels. So we might learn something. And if I can't get answers with the 223, I might drag out the 220. That old gun will really shoot and was set up for me by a real pro. It's just so darn loud that my wife will be on my case well before I've shot all the rounds I'll need to shoot. So...I'm taking the wise path for now and using that 223.
It's good to be retired. A bad day at shooting beats a good day at work.