Save your lrbho! - Spikes Tactical 9mm Buffer Spacer

A simple but very effective product. I bought two of these for my AR9's. It stops the bolt travel just behind the bolt catch. If you have a last round bolt hold open (LRBHO), it'll stop the bolt just behind the catch so it doesn't have enough room to hit the catch and break it. I put a couple hundred rounds through the gun with the spacer installed and it didn't hinder performance at all.