DPMS has a block that I purchased for about $40 plus shipping, its served me well but does flex a bit. I took a long hard look at the Geissele tool, it attaches to the barrel extention so should provide a rock solid link up. Its expensive tho....as if Geissele makes anything cheap.
Assumption is the mother of all ****ups.
Know what you know, Know what you don't know. -Paul Pedzolt
"Jack of all trades, master of none, though oftentimes better than master of one" -Mynshul