EDIT : And the answer is ......................

[kirby999]

For all you guys that have more experience with this than I do . I'm looking at lowering the power of my R9 and R11 . The factory spring setups that came in the R9 and R11 came with a spring and rear guide , the Macarri kits came with a spring(slightly shorter ) , rear guide and top hat or front guide which adds to the preload of the spring . If I remove the front guide (top hat ) wouldn't that remove some preload and reduce the power generated by the spring? I also have a couple of Tarantula springs I could install if that would reduce the power . I'd love to get them down to close to what my HW97K is shooting at 810fps. kirby

[kirby999]

And found out a few things . The R9 had a Macarri econo tune spring kit in it and the R11, a Hornet kit ; that I had already installed before . Both had tophats and rear guides . They both shot CPL's at around 925fps and I was hoping to get them down to 825-850 when I was finished working on them . The R9 was first , I changed out the spring for a JM Tarantula spring and kept the tophat and guide from the kit . After a few pellets through it I check the progress over the chrony and was getting 900-905 fps , a little drop , but not enough for me . I removed the tophat and reinstalled the Tarantula with the rear guide ; it was a lot easier to put back together the second time without tophat and the spring was set . After assembly , I shot a few CPL's to get sighted back in and to get things all set inside. The rifle seems easier to cock and is a little bit quieter . Across the chrony I'm now getting 875-885fps . Not as much as I hoped for but it is smoother cocking and shooting , not a great deal , but enough to tell . Next I did the same with the R11 , changing out the spring , keeping the rear guide from the kit ( a tight fit ) and not using the tophat . BTW , I relubed with tar each change . After assembly ; some shoot in shots , I wound up getting the same result with the R11 . 875-885fps . A little smoother , both cocking and shooting . Now all I need to do is shoot them and get everything broken in before a final verdict. kirby

[gamo2hammerli]

Good going.  Sometimes a little less is a little better.  Don't care how powerful or fast the pellet is.....if it don't hit where you want it to....it don't matter!!!!

[tjk]

Hey Dave, have you tried buttoning any of those pistons?!? I think the slight resistance  of the buttons may bring you closer to your intended velocity goals. Makes for a smoother cocking and firing rifle. Just a thought. tjk

[Gene_SC]

Just a note Thomas... Buttons are intended to take the piston slop out when installed in the cylinder or chamber. You should not have any resistance at this point. Really not a good idea since the buttons are very small and can get disloged easily. The buttons are strickly for a closer tolerance between piston wall and cylinder or chamber.

[tjk]

Your point is dually noted Sir Gene. Yet I've had great results with the buttons. I installed them on the piston itself though,...where I noticed some scuffing on the piston where it contacted the compression chamber near the rear. If installed correctly, they should never come loose,....as Macarri states in his installation instructions. I sanded them down to just a slightly" lesser than snug" fit and applied an extra dab of moly to them before installing the piston back into the reciever. So far I haven't had any problems with this piston tuning  method. Not trying to be argumentative in any way,...just sharing what has worked for me. I know I'll be ordering more of these buttons in the future!! Thomas

[Gene_SC]

Clearly noted Thomas, I miss read your post thinking you were fitting them as a resistance fit. I will tell you this though. I have used a similar method and made it an almost zero tolerance fit but piston without the seal on it, the piston would fall to bottom of chamber as tested with the mod. It actually increases the FPS..:) I have tested it several times. Taking out the slop and with a nice fit it really does increase the fps and overal smoothness of cocking and shooting cycle as well. I have not found that it will decrease the fps at all.

[tjk]

Thanks Gene, I was afraid I may have started a "tuning method" battle after re-reading my post. Clearly not my intention. Yes sir, the buttons make a nice improvement to these Chinese made shooters. I didn't notice much increase in velocity, but with the JM parts, the G1's FPS actually dropped off a bit. Factory condition, it was in the 870's. Post tune it's averages are in the 830's with SD's but a very consistant 850 with JSB's and FTS's!?!?!?! Funny how finnicky these shooters can be with different pellets! LOL's Still a very smooth rifle, and just the right speed for my shooting needs. Thomas