If you had a rifle with a 5.56 NATO chamber and a 6mm tube, then it most likely could be loaded to NATO pressures.
Given the fact that the 6x45 is based on a 223 Remington chamber, then the lower pressures are applicable.

Originally Posted By: WWAYote
Any reason that 6x45 load data is held to around 50k psi?

If loading for an AR 6x45 with 5.56 brass, a system with max avg SAAMI pressure spec of 62k psi, wouldn't one be able to safely approach similar pressure levels?

Just because you are loading 5.56 brass does not mean your chamber can handle pressures of 62k psi.

Edited by eneranch (03/16/14 05:13 PM)