Since the .308’s pistol grip install is a little different from a mil-spec AR15, here are instructions for properly installing the ERGO SureGrip, or any other kind of AR15 pistol grip on the Windham Weaponry .308. To purchase an ERGO SureGrip, please see the link at the bottom of this article.
Note that the little rubber trigger guard spacer that comes with the ERGO grip is not needed on the .308 since the trigger guard is forged into the receiver and not a separate piece.
First make sure rifle is unloaded then push out the pivot and takedown pins and remove lower from upper. Holding the lower upside down remove pistol grip screw with a 3/16″ T-handled Allen wrench.
Pull grip straight up off lower. This will reveal the safety detent spring and the takedown detent spring. The safety detent spring will come out of the pistol grip. Leave the takedown pin detent and spring in the lower receiver and keep the lower on the bench as shown. This way you will not lose the safety detent or the takedown detent or spring.
Usually the pistol grip washer will be stuck in the rubber inside of the grip. Going through the top side of the pistol grip hole with the Allen wrench you can dislodge it from inside. Once you have done that put the washer on the pistol grip screw.
Put the safety detent spring in the hole in the ERGO grip and carefully push the grip straight down onto the lower. Be sure to compress the springs straight down and not to bend them over.
Screw pistol grip screw back on until it is snug and the grip is solidly on the lower. Push rubber plug into the bottom of the grip.
Do a check of the takedown pin to make sure it is still held securely in place by the detent. If it pulls off in your hand remove grip and reinstall using the pictures above as a guide to the proper orientation of the takedown pin.