Powder Compression

[Don McDowell]

Klaus I think you're actually asking two questions.
Yes you might be able to get by with a 60 gr charge for accuracy, but depending on the bullet and the twist rate of the rifle, that bullet might very well loose stability at 3-400 yds due to the loss of velocity and the slowing of the spin. (think of a bullet as a childs toy top, spinning fast it stands up nicely, when it starts to slow down it starts wobbling and falls in no predictable pattern)
And then there's the fouling issue, many times a lower charge like the 60 gr charge will foul excessively due to the lower pressure and heat generated by that charge.
For the most part if you can compress enough powder into the case and not bulge the case head and get accuracy you're in good shape, it won't matter if the powder is a solid cake or not unless for some reason you decide to pull the bullets and recharge the case.....