I use the RMP buttstock 6” extension with the RMP rifle rack (RMP 15.25 x 25) to secure my DDM4 in my 2008 Toyota Tundra. The extension adds just enough length to the rack so my rifle keeps a lower profile. This setup met my expectations and is exactly what I was looking for in a product. I know my rifle is secure when I’m on the road, easily accessible, and immediately ready to put into action. I highly recommend GMT gear to anyone looking for a quality American made solution for their tactical gear.