Bradi, these seem sold out at online retailers. I would check on large gun and accessory sites like (6)un (8)roker as discontinued and hard to find firearms and accessories show up for sale by private individuals and small shops. Just replace (6) & (8) with G & B.

You might have to get one via private party or through other sites, if you can find them in stock. One place you might have luck starts with Arms and ends in List. Another sight is the Broker for Guns. You might also want to try online forums, as you might get lucky.