I recommend .45-.49g, they'll give you the best range and accuracy.
That spring fatigue thing is ridiculous, BB weight has nothing to do with that, but leaving you gun cocked for hours does.
For stuff to prepare your rifle, wrap the middle of the piston in copper or lead wire and then tape to get it to 50-65g, and then put it back in your gun.
This will alter your pressure spike and allow you to show heavy BBs more easily.
That spring fatigue thing is ridiculous, BB weight has nothing to do with that, but leaving you gun cocked for hours does.
For stuff to prepare your rifle, wrap the middle of the piston in copper or lead wire and then tape to get it to 50-65g, and then put it back in your gun.
This will alter your pressure spike and allow you to show heavy BBs more easily.