COAL with 69 Sierra HPBT Match

Developing a load for my Savage 12 in .223. Varget working the best somewhere around 24.5 - 25 grs. Lapua Brass trimmed to 1.752.
Using a RCBS Competition die 37201. My COAL is varying about +/- .008. Shooting for 2.260. Checking from end of case to tip of bullet.

Ordered a Hornady bullet comparator to start checking at the ogive.

BUT......What would cause the COAL to vary so much? Does this affect accuracy?

Your seating die is not seating your bullets by length. It seats them by depth of some predetermined diameter that the seating plug is machined to. The difference you see is the variance of your bullets from that predetermined diameter to the tip. It will become clearer once you have the comparator and can set the ogive length rather than the COAL.