In my opinion, the third fastener is simply a back-up safety block against the rifle opening on fireing! Many discount the value of third fasteners, especially the so-called greener cross bolt, but they are all valuable IMO! The greener cross bolt, if properly fitted is just as positive as any other type of third fastener. Are they needed? NO,in most cases, Do they make the rifle more secure? YES they do, but it is simply up to the buyer, to decide how valuable they are to him. For me, I want them!