One difference between Dicks and yours is the way the bends are formed...his are nice and smooth, gas likes to flow.
you could mabe get a larger pipe to replace the small one on yours or try cutting it down a little...its all things combined that will get you.
I have a brand new DA with a 22/10 that does better than that although with a Pitts style Jtec. Outlets are probably 2x yours x2 but the Hogs and Turkeys nearby dont care