The Benelli was designed for the Marines and put into use by them. I am a Marine and we use it often. The stock collapses so that when you are wearing body armor and all of your gear you still have the proper cheek weld and length of stock. Think of all that gear as a stock extension. For those of us who do not use body armor, it works to shorten the overall length of the stock making it easier to do house clearing and movement without shortening the barrel and round capacity too much.