I know this is an older post, but as I'm new I can't PM folks yet. I recently moved to the Black Forest and had the same air issues. Dive shop could only get my tank to 2600, CSFD would fill to 4500, but did not have an adapter...so...bought the big Air Venturi HPA compressor. I have 6 acres and a decent range set up. Shoot up to .357 currently, and my AF Texan LSS CF .50 is in the queue at the factory. PM me if anyone is interested in meeting up. I shoot at least a couple times a week.