My SWD Mac 11 which I run a lage Max 11 upper on had the back plate of the lower receiver crack fully on one side anyone know a good shop that can weld these guns?
Chances are it was run without any or with a crappy buffer before you owned it or you just had sub-par welds. Some of the TX guns are known for crappy welds. 86 guns are known to sometimes have been poorly welded during the rush before Hughes went into effect.