Below are pictures of the buttoned piston and compression tube. Two sets of three buttons on each. The lower picture shows the relationship between the piston and the tube in the cocked position ready to fire. The rear set of piston buttons positioned 2.25 inches from the seal front, are just at the rear inside edge of the tube and center the piston in the tube. The compression tube is centered in the main action tube via its front and rear sets of buttons and the rear of the piston is further stabilized by its cocking rod riding in the rear guide tube. There is no metal-to-metal contact.
I cut 3/32" off the piston seal at the front This increases the stroke and makes the sealing lip thicker and firmer. The pictures below compare the cut down seal to an un-altered one. This modification alone was good for 10fps or almost a 1/2 fpe power increase and a little smoother shot cycle. I also sized the seal down a little for a correct fit in the comp. tube.
So now with these modifications so far using the un-spaced factory spring and rear guide the power is up to 925fps from an unmodified 915 and already feels much smoother for a total investment of about $1.50 worth of plastic and Crazy Glue. Plus a couple of evenings of fun. But there is more.
The next pictures show how to make a custom set-back trigger with all factory parts. The first picture shows the relationship between the OE trigger position and the new position. The second picture shows where I cut the gold painted blade off its base and the new re-shaped blade made from another Reckord blade is grafted on to the base with a self tapping screw. Also note how much was cut off of the adjusting screw to clear the way. Setting back the blade like this improves the reach to blade and also changes the blade leverage. This trigger breaks at 6 ozs. and is perfectly safe. The first stage doesn't hang up and can be freely rocked back and forth with the gun cocked. BTW to decrease the first stage on a Reckord you just bend back the front rest tab. The third picture shows how the trigger looks in the guard.
Again the cost was a few hours of fun and one self taping screw. I happened to use another blade that I had already re-shaped because it told the picture story better but the blade you cut off can be re-used. Tools are a razor saw, a couple of files, the Dremmel for re-shaping which isn't even necessary and a drill and bench vice. Nothing exotic at all, just measure twice and cut once carefully and on the square. You are working with aluminum parts here and the cutting and shaping is easy and fast.
The next picture shows how I modified the front arm catch to make it smoother, easier and quieter. The slight radius that you can barely see at the entrance to the arm button retainer socket makes the arm release and return much smoother. I also moved the entire brake and latch assembly forward on the barrel about 3/32" so that the arm button doesn't go as far into the socket.
The brake is retained on the barrel by one set screw and a little thread locker. It came loose with a some penetrating oil, hair drier heat and not much twisting force. Then I permanently red Lock-Tinted it back on in the new position. The location was such that I could just not force the arm out of the retainer socked by hand without using the release button. It releases and returns real nice now. The front cap of the brake screws out with the aid of a 7mm Allen wrench inserted into the front cap muzzle opening. This provides access to the inside of the brake and I installed three finishing washer baffles. I also pressed a small washer into the recess inside the front cap to reduce the muzzle opening from its 7mm hex shape to a .23" round hole. The already quiet gun is now even smoother and quieter.
Here are pictures of the finished gun in the factory beech stock. I added a third center diamond point to the grip panels and re-cut the checkering and borders to sharpen up the diamonds and clean all the factory finish out of the grooves. Then the raw white panels were re-colored for a perfect match with Birchwood Casey water based Walnut stain and given a couple coats of True Oil with a tooth brush. I also added a third pointed bordered panel of matching 18 lpi checkering to the fore-end belly and colored and finished it the same way. Using a narrow border checkering tool, I then cut a narrow molding along the top length of the fore-end wrapping around the nose and connecting with the top grip panel points.
The factory finish was oil sanded (3M Imperial wet-or-dry paper and Sheath oil), being very careful not to burn through at the corners. I started with 400, 600 and then 1500 grit and then polished up to the high gloss with Meguires #9 swirl remover auto finish detailing polish. This isn't a particularly well figured blank, and although I usually don't prefer high gloss finishes the glitz really helps out this time, I think.
The final phase to the action tune was to change to a Maccari R-9 Tarantula spring on synthetic rear and front guides spaced up. This brought the power up to 955fps/16fpe with the modified HW piston seal shooting Pre 7.9s. The shot cycle is of course much quicker and and the cocking force didn't increase at all.
Then I changed to a Venom R-9 PowerPulse seal and the power is now up to 985fps/17.02fpe with 7.9s and 960fps/17.19fpe with 8.4 JSBs The added smoothness with this seal is very evident. There is really something to be said for correctly matched tuning components and this combination is a proven winner time and again.
This is a very quiet, silky yet powerful gun. It meets my indoor off the bag standard of stacking pellets into one hole at 10 yds. My total add on investment was under $50.00 and I had a real good time doing the build up. Distance shooting will tell whether the Premiers or the JSBs win out. All I need now is some warmer weather. JK