Dumb Questions re: .30-06 - COAL

[DJL2]

I believe the spec COAL is 3.34" for the .30-06. I note any number of recipes and load data that lists a significantly shorter COAL. As an example, from Hodgdon:
208 AMax Hodgdon H4350 .308" 3.285"
165 GMX Hodgdon H4350 .308" 3.225"

The Hornady factory loaded 178 ELD-X was similarly short.

That seems an oddity. Why spec a COAL that long if it doesn't make sense to load to it based on case length and projectile length?

 

[FLIGHT762]

Simple, it depends where the ogive sits on particular bullets. On some bullets, 3.340" might shove the ogive into the lands. Homogenous bullets like the GMX like to be seated .050" short of the lands.

Anyone who has done a bit of maximum measurements to the lands knows this. Different bullet shapes will allow seating past the Max COAL (3.340") some may not depending on the reamer used in chambering the barrel. Custom chambers may have shorter throats where factory chambers may have longer throats allowing bullets to be seated further out.

As an example, my factory chambered Winchester model 70 classic hunting rifle in 30/06, a Barnes 150 gr. TTSX will hit the lands @ 3.335". A Hornady 150 SST hits the lands @3.285", a Hornady 150 GMX hit @ 3.268". It would be a mistake to seat some of those bullets out to 3.340".