Alexander tells how they tuned the Silverback Airsoft SRS-A1 to 170m/s in this Red Army Airsoft video... "In this issue, we will be tuning the SRS-A1 spring sniper rifle from Siverback Airsoft. We test two 13mm VSR springs of the M160 and M170 type. We test the steel guide with Teflon tube and bearing for a better setup. We'll put a new rotary hop-up with a quick adjustment. We'll install a new trigger with adjustments to the landing height and a finer adjustment of the free wheel."