You may have a restriction at the bolt probe, time to center drill, bob and install an extended one. Look for the little flags in peoples yards from lawn spraying companys and wire locaters. Ask if you can have one when they are done with them, the wire is just a hair over 1/16th inch in diameter and will work good for a probe, a good 2 part epoxy glue holds them in place just fine. I've gained 50 fps on some rifles by doing this. Also check your valve stem seal, if it looks ragged sent it to Alan at AB Airguns in Kansas, he will replace it with a new material that will help the fps, just make sure you don't get any dirt in the gas tube as these seals will not seal with dirt in them. I have gotten an increase of about 40 fps on some rifles with these seals and use them in all of mine that I sell.