I think you need to hook up with somebody that can show you how to reload.

There is no proper COL for a 1:7 twist 26" barrel. It does not work that way.

Either you load them by the manual to sammi lengths to run through a magazine
or you load them long over sammi length to either jump or jam the bullet in the rifling
and you have to single load the cartridges, IE they will not fit in the magazine..

That allows you to tune the accuracy to some degree along with a lot of other things.

Assuming you are loading 223 1.76" is the max case length and 1.75 is the trim length so something does not sound right.

The max sammi COL for the 223 is 2.25"