I bought some anti-walk pins for my AR from JP, then realized that they don't work with standard trigger parts (requires slightly larger pin holes). When I called them, they confirmed this, but said they would ream my trigger parts to fit for free! Not only that, but I forgot to send my disconnector, and rather than delay shipment, they took one off the shelf and included it for free!
I highly recommend JP Enterprises, based on their excellent customer service!
SAB