Sand-blasting cabinets?

I have the same blaster Glenn and my compressor is only 9.7 cfm @ 90 psi and it powers it fine. Definetly sounds like a screwed up gun to me. Why don't you just take your receipt along with the gun back to Harbor freight and tell them you have it already loaded with sand and it'd be a ton of work to return it and see if they have another gun to swap you? They have been pretty good with me when I got defective stuff.