Roadkill

My new off ebay SL-68 II isnt shooting fast enough. Its shooting about 180-183, with the velocity screw turned out as far as it will go and still be able to pump. One of the guys at the feild said he had one at his house and said the problem probably had something to do with the cup seal. I havent taken it apart yet but i will later to have a closer look. I held the marker to my ear and couldnt hear any leaks so i dont think thats the problem.

Any one have other ideas what the problem might be?

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Black/Blue WDP 05 Angel Speed
Tippmann SL-68 II
Smartparts ION
2k2 Cocker
VSC Phantom

My aim = Roadkill1214
Tippmann Owner #27
Angel Owner # 48