In the 2023 and 2024 models I did a lot of testing. I tried just about every size available. I spent over a month testing the magic number is .223. . 218 and .219 are too small
The bore diameter is bigger than that.
ABS 26 grain and varmint Knockers 28.5
I was getting the best results with.17.5 to
18 MPA AND run them at 950 to 1000 FPS With the varmint Knockers.
15 to 16 MPA with the 26 grain AVS at the same speed. Check out the K1 I have for sale on eBay. I have a picture of the groups. Hope this helps.