Cutting Rail Guards:
Some rail guards come cut to length such as Mag pul ,and some others.
If you need them shorter for lights and such you will see that they are segmented.
They recommend you use scissors ,but unless you have scissors from Hell ,this can be sloppy.
Take a cutting board ,and a large wide sharp knife or cleaver and place the rail on the cutting board ,and place the knife in the grove between the segments of the rail cover where you want it shortened.
Make sure all fingers ,and other body parts are clear ,and that you have lined the knife up straight with the groove ,then have your buddy who hast been drinking ,whack the back of the knife gently,with a mallet ,hammer ,and not his hand or head . the segment you dont need will just pop off ,and a smooth factory cut will result.
Step back ,count fingers ,count buddys fingers.