COAL is really only important (if you cannot measure OGIVE) for making sure the round will fit and feed from your magazine. Since most people only have the tools to measure COAL, the reload data only provides COAL which gets you close. The poor man measures his bullet seating via COAL, the target loader uses the OGIVE which is far more precise than COAL.

If your loaded round will fit your magazine and your OGIVE measurement is less than the max, you are golden, COAL becomes irrelevant.

Rosewood