The difference is that the GAU-5/M11 are both currently sitting in the inventory and can be a quick fix. The brief I saw had a conversion price of less that $800 for the new barrel, rail, and BUIS. We spend more than that the latest gucci rain gear. Throw an M68 that's LRS probably has laying around and you have a SBR that will be as effective as anything we currently have (for 95% of the shooters) and be easier to egress with. If the SPO would ever approve those rifle racks used by the Army, we'd really be in business.