Yup, fore shore, yubecha, dawgone right you better reduce max loads when using US military .30-06 and .308 brass. It's measureably heavier/less internal capacity than *most* commercial of those calibers.
Less difference in .223/5.56mm.
Read your load data. MUCH has actually been worked up using the military brass. Derrick Martin of Accuracy Speaks has found that the Lot 95B batch of surplus 4895 powder cannot be crammed into the .223 case with a heavy enough charge to get best-accuracy launch velocities with certain heavy Sierra Molycoated bullets. It's too "fluffy" and you run into compressed loads before the pressure and velocity get up very high.
Do NOT translate this info to the standardized blend of 4895!!!!!