hmmmm so you took the lower pressure hose off and found small round bb type objects in there???
i highly recommend that you go with duracool. it runs at a lower pressure than r134a and that means less leaky seals and longer life for the compressor.
my high pressure line from the compressor to condensor had some pitting happening on the inside... i had it blown out with nitrogen and since last year around this time it still works

i highly doubt that the bb's are from your compressor though... as they would need to pass through the receiver drier.