I actually bought the magpul stock thinking the same thing about welding on an end piece, took it apart, and had the same reaction and decided to check here and get my name on your list to get one when it's ready.Thats what I did for the MPX stocks way back - made new rails. Its cost prohibitive for the MP5 because of the 'L' rail shape. If I could get raw extruded section it would be possible. I've even thought to weld rails together but that is starting to get to be like work. All this effort for something I don't even need