Quote:
Originally Posted by DWalt
As some previously mentiond, the COALs given are often predicated on the maximum cartridge length which will fit in a minimum magazine, nothing else. The optimum COAL for a specific gun may well be longer than some handbook's maximum COAL.. . .
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Load manuals specify the COAL they tested at . . . besides it being within SAAMI specs, that's all you know.
Pistol COALs in load manuals are actually the MINIMUM COAL for the powder range suggested. You are encouraged to go longer (lower pressure) if you need it to feed. Shorter increases pressure.
Rifle is a completely different animal, where pressure rises in MOST rifles as COAL increases and the bullet gets closer to the lands.
However, in some rifles (eg an old Rem 700 30-06) the chamber is so large that for some bullets pressure will often decrease as you increase COAL just like pistols . . . up to a point where they MAY get higher pressure depending on the length of the chamber vs the bullet you chose. For some bullets you can't get close enough to those lands before the bullet falls out of the case lol.