Hey bro, some people will probably arrive at this post to give you a lot of dumb comments. Ignore those. The reason is this question happens a lot. But i see your a new player so dont sweat it. Basically the weapon engrams xur sells are legacy engrams. Absolutely none named "legacy engram" will ever decrypt to a year 2/taken king gun. Theyre intended for people missing weapons to complete their yr 1 sets. So save your coins bro and dont buy em.