How do you adjust the velocity of a stryker cybrid paintball gun?

I got a Stryker Cybrid Paintball gun from wal mart and it works good but it doesn't say in the manuel how to adjust the velocity. If you know how to adjust the velocity please answer.How do you adjust the velocity of a stryker cybrid paintball gun?Velocity adjustment should be an allen screw on the back of the marker right below the bolt. Clockwise to increase, counter-clockwise to descrease.