I am new to this forum and have an old sr5 that I bought 2nd hand from my local retailer. The gun itself has never been gamed, barely shot and basically mint for a 2009. I chrono'd it recently bone stock and got about 330 fps on a .20. After some mods: lonex ported piston head, shs poly w/ steel gear piston, sorbo padding, 110 spring, reshimmed, lubricated, shs high torque motor and mosfet, the gun fps'd at 350 on .2g . The gears and most internals are stock except for those listed above...I did these for durabilities sake. I did my research and my cylinder is ported all the way to the rear which means the gb is a low serial number sr5. The aoe has been redone and pre engagement has been eliminated as a result of the 2009 stock spring being replaced with a 110 and lightened piston head assembly. An important fact is that we had a sr10 upper reciever with a stock barrel and we placed my sr5 lower reciever for testing....we got 400 fps on the dot... so we know that the gb is actually shooting ok..(could be better with oring nozzle and hop up bucking). So my question is...Do i need to look at the cylinder porting? do i need a tight bore? Ive had my fair share of airsoft back in 2008 then i went awol and now im back
From all my research it seems to be that i need a different version of cylinder apparently the newer sr5's had that. Its funny to think that my stock sr5 when placed on a 360 + mm barrel will actually shoot 400 fps. my guess is that the point at which the piston is about to produce maximum psi, the round has already exited the 227mm barrel.
Thanks in advance for the assitance!
Edited by carbinenewb, 07 February 2014 - 10:28 PM.