I concur with the previous poster urging caution -- to the point where I don't even bother loading sub-minimum magnum loads (aka, heavy special) anymore. I load specials in special cases, and magnums in magnum cases.

I suppose a careful person, with the aid of a chronograph, caution and a bullet/powder combination with both a special and magnum published load could probably carefully reduce the magnum load below the magnum starting point.

But I'm not sure what the point would be. Even though the gap for the same bullet/powder combo in Special and Magnum loads appears to be 4-5 grains, in my opinion there's not a ton of difference in recoil or terminal ballistics between the "max" Special loading and the starting Magnum loading.

I've shot a lot of 180gr JHPs as maximum Specials and magnums; about the only real difference was that I found the Specials slightly easier to shoot one-handed.