i have no experience with the palmers brass, but the ported brass will be quieter than the non ported brass. thats why your friends cp is quieter than your flatline. but personally, i wouldnt trade my j&j ceramic for anything. its very accurate, and quiet (at least its quiet for an a5) and i have only had one ball break since i installed it, and shot a little over a case through it. the best part is that it self cleans when a ball does break. and btw, if you get an apex, you can put the tip on most barrels

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Tippmann A-5 "Tweek"; 14" J&J Ceramic, polished internals.