They will actually soften a touch. Think of it as a stick that is 8 feet long... It will play softer at 8ft then it will at 6ft or 4ft or 2ft. So if you take a stick at 8ft and tip it to 7.5ft then you know that it has stiffened just slightly. All shafts will play this way!!!

Now with most shafts and the Rifles are no exception, the butt of the shaft will not stiffen the shaft as much as the tip of the shaft. So if you were to take .5" off the butt its not going to stiffen as much as taking the same amount of the tip. Same goes with adding length.