Ripstop,
But using the same grained bullet with less powder(under loading) than recommended can cause More recoil too, right?
I wouldn't suggest using less powder than recommended.
Reloading books usually state a high end and a low end for powder charge with corresponding fps. Sometimes the book states a powder to use as a reduced load. This load is the lightest recommended load for reduced recoil. They never suggest this for accuracy, just recoil.
Just pulled out my Speer Reloading Manual #13. Now you are making me work.
.308 Win. 150 grain FMJ
H335 powder @ 47 grains - muzzle velocity 2879 fps
H335 powder @ 43 grains - muzzle velocity 2562 fps
Dropping 4 grains also drops 300 fps which will reduce recoil.
Reduced Load
SR 4759 powder @ 25 grains - muzzle velocity 1925 fps
SR 4759 powder @ 21 grains - muzzle velocity 1632 fps
Using this charge will reduce recoil to the point where your auto loader may not cycle.
What I am getting at is that you do not have to change bullet weight. Picking a powder that gives you a lower fps and staying on the recommended low end will give you reduced recoil because of reduced speed with the same bullet weight.