I have a new 10 FCP-K in 223. I measured the lands with a Hornady OAL tool with a Nosler 69 gr HPBT.
I have several measurements from 1.885 to 1.971. I tried to use the same pressure each time but I guess I havent been.

I was planning on using 1.966, because that came up more times.

Any suggestions for a more accurate measurement?