[CarWiz]

I think the "better gun" charts are in error or it's for a pressure blast system. A 1/4" nozzle won't even pass 80cfm of air alone much less adding abrasive. It's more like 21-22cfm of air so the 17cfm is probably pretty accurate for 6-7mm with abrasive. There's two different air requirements depending on whether the system is siphon feed or pressure feed. If your system is like most boxes, it's siphon feed. Also, the air jet size is different than the nozzle size. Simply adding a larger nozzle won't increase the capability of a gun. The fixed air jet size has to be considered and is generally matched to a specific nozzle size or range. The same goes for the feed line or hose.

Most charts are developed by compressor manufactures and their compressors have been over-rated for years. Their purpose is to sell compressors. True flow rates don't come near actual flow through a hose or fittings so chart specs will indicate a higher cfm compressor is required. If your compressor can indeed output 35cfm, you'll need a minimum of 3/8" air feed fittings and hose. It should be able to handle a 5/16" nozzle with no problem. If your willing to wait while the compressor catches up occasionally, 1/2" hose with a 3/8" nozzle will give adequate blasting.