I've decided to share a few things I did to my Gamo Arrow to restore the gun to better than out of the box performance. I have more constant shot strings; the FPS drop is nonexistent for the first 40 shots. I'm seeing tighter groups at 50 yds, and the gun is even quieter than it already was because you can't hear the hammer spring rattling around in the plastic action. This is by no means an end all be all write up and it's your gun. Do as you wish. It made a night and day difference in my gun and maybe it will help someone else who has given up on their Arrow. You will need two things other than disassembly tools. You will need heavy duty 3% moly grease that is used for farm equipment. Easily found at Tractor Supply. You will need a rubber grommet from a vaporizer coil head. I'll attach a picture. If you don't vape, a Vaporesso M2 coil head can be purchased at nearly any vape shop for a couple dollars or less. Start by removing the two screws from the rifles stock and pull the main assembly of the gun. There will be 4 small torque screws holding the plastic cover onto the action that contains the bolt, hammer spring, hammer, etc. Remove those 4 screws keeping pressure on the cover so your hammer and spring don't go flying! I used a small scribe to hold the hammer spring and hammer in place while removing the cover. Then carefully remove the hammer spring and hammer. Clean all the grease off of the hammer spring, hammer, and anywhere in the body these components will make contact or be guided by. Next coat the hammer spring and the guide area of the body that traps the hammer and spring, including the underside of the cover that traps the spring with the heavy duty 3% molly grease. I simply painted it onto the spring and chassis areas with a small arts and crafts paint brush. A half mm or so thick layer is sufficient you just don't want globs of it about. Now pull the bottom contact from the coil head and remove the rubber grommet from it. I used the M2 gromet because it fits the spring perfectly. Insert the narrower end of the gromet into the back of the hammer spring. The wider lip should just cover the diameter of the spring. Now put it all back together with the gromet to the rear seated against and around the spring guide. The easiest way I found to reinstall the hammer and spring is to put the spring in place with its new tension preloading gromet at the rear of the spring and insert the hammer into the spring. Push the hammer backwards with your finger, while holding the spring down so it doesn't fly away, until the hammer engages the sear. Flip the safety on. I used a scribe to apply a small amount of pressure to the hammer and spring, right where the spring goes around the hammer, to hold it in place while re installing the cover. Once it is almost all the way on you can slide the scribe out and avoid flying parts. If you let that hammer come forward and strike that valve while the gun is apart and out of the stock things will get messy, you might get hurt, and you might break something. Take care and be mindful of what you are doing here. Finish re assembling the rifle. Now your hammer and spring will be free to slide back and forth easily, the moly grease helps dampen spring rattle, the preload and moly grease added to the HS will cause the HS to strike the valve just a bit harder. This translated on my end to a more accurate rifle, higher FPS, 793 FPS AVG with 14.3g CPHP vs. sub 700 FPS before, and the first 40 shots being extremely consistent in terms of velocity. My best educated guess is the volume to be filled with air when the valve is opened is maxed out each time before the valve closes again. This wasn't happening before the modifications. It's obvious because of the steady but incremental drop in FPS. Works great for me and my Arrow is a joy to shot once again. Hope this helps someone out.
