I am still fairly new to reloading, and thought I had a handle on ogive, but I guess not...

Background: Savage 11/111 Trophy Hunter XP in .223, Nosler 69gr CC bullets. The brass I normally use is being tumbled, so I used some Federal American Eagle brass that I have resized and fired a couple times in my AR. I full length sized the brass and it is a little shorter than trim to. I grouped it by length, and ended up loading a group of 1.746 length.

I used a Hornady OAL tool and measured with a ogive tool to 1.971. I decided to load 3 4-shot groups at ogive length 1.941, and 3 4-shot groups at ogive length 1.891. When I got to the range, many of the rounds would not chamber in my gun. Many of the 1st batch were 1.941 - 1.943. However, 4 of the rounds were 1.939. Of those 4, 2 would chamber and 2 would not. In the other group, I grabbed 2 rounds and both measured ogive of 1.889. Again, one will chamber and one will not.

I am thoroughly perplexed by this. What could be causing this? How can I have a round chamber, and another round with the shorter ogive length not chamber?