New 11.5fpe .177 R9 setup.

[nced]

A while back I had my .177 R9 tuned to around 12fpe and actually liked it a lot, especially the low cocking effort required, the nice shot cycle, and the accuracy. After a few years the spring I used for the 12fpe-ish tune broke and I was down to my last light wire (34 coils of .120 wire) spring and I've been using it, however my minimum velocity was around 900fps with CPLs using the new style HW95 piston seal and Ultimox 226 lube.

Well....today I was rummaging through my "old parts bin" and found a spring with 30 coils of .125 wire wound with a .540 id and decided to give it a try.  The first thing I noticed was that the 30 coil .125 wire spring only needed about 3/4" of preload to install. The next thing I noticed was that the cocking effort was VERY easy and the really nice shot cycle was putting out CPLs at 815fps! Did a bit of accuracy testing upstairs and the 11.5fpe tune allows me to "touch pellet holes" at 18 yards upstairs shooting sitting on a bucket resting the gun on cross sticks.

Anywhoo.......the .125 wire spring with very little preload is certainly a nice setup for my R9 and I think I'll explore the virtues of a .125 wire spring lightly preloaded vs my normal .120 wire spring with consideeably more preload.

Just mentioning that I'm a bit surprised by my 30 coil .125 wire spring!
 

[JimL911]

Ed, what was the length of the spring? I'd like to get mine down to those levels.

[nced]

Ed, what was the length of the spring? I'd like to get mine down to those levels.

Just for you my friend I broke down my R9 and measured the set length of the spring and amount of preload.......
The length of the spring is about 8 3/4"...


I do like to add a Delrin "thrust washer" between the spring seat and the end coil and for this tune I added another Delrin washer behind the spring guide flange to boost the CPL velocity a bit to 815fps from 800fps. I used a steel top hat for this arrangement however I've been known to use a Delrin top hat with a steel flat washer between the top hat and the piston face. I usually play around with the velocity a bit till I get near what I want by adding/swapping out Delrin and steel spacers, however this assembly gave me the velocity I was looking for with the third try of "top hat and washer spacing.........


I do have to mention that the R9 I have was set up "forever" with an oring sealed piston cap and as such the inside of the receiver was finished very smooth for oring sealing and I do know that some airgun gurus claim that a crosshatched surface is needed for the factory seals. Personally, I haven't found this to be true when lubing with Ultimox, but perhaps it is necessary with molly paste and such.

When I received a new HW95 piston I noticed that the installed piston seal was redesigned by HW and it now had a thick parachute edge and reduced sides........sooooooo I opted to try it directly in my R9 without any mods except for some Ultimox 226 lube. When I first shot a CPL over the sensors with the previous .120 wire spring (34 coils) I got a velocity VERY close to what I was getting with the "tedious to fit and cut" oring sealed piston cap I was using (CPLs at 900fps). I had been using the new style factory HW seal and Ultimox in my gun for the prior year and it worked well for me, however, when I "discovered" the rather short .125 wire spring in the parts bin I had the notion to try shooting at 12fpe-ish again. The problem with the 34 coil .120 wire spring was that even with minimal spacing I couldn't get the CPL velocity much under 900fps since it was a tad over 10" long which gave about 1 1/4" more preload than the .125 wire spring I'm currently testing.

Anywhoo........I do hope that the new factory seal holds up for the long haul because it's simpler to fit it to the piston than cutting and fitting an oring seal. Here is a pic of the progression of HW95/R9 piston seals through the years......

LOL......the latest HW piston seal is still coated with the tan grease HW uses for lube after pulling the piston!

Hope this helps some!

[Dockey 454]

Good report Ed, thanks. Looking forward to see how this all works out.
   Tom

[JimL911]

Thanks Ed.

[chuckinohio]

  As usual, I learn more from a single post by Ed than a whole weeks worth of reading elsewhere.

  Thanks for the insights, and the time taken to share Ed.

[Tinknocker1]

  As usual, I learn more from a single post by Ed than a whole weeks worth of reading elsewhere.

  Thanks for the insights, and the time taken to share Ed.

x2

i guess im not the only one i read his post on all the forums 

[chuckinohio]

  As usual, I learn more from a single post by Ed than a whole weeks worth of reading elsewhere.

  Thanks for the insights, and the time taken to share Ed.

x2

i guess im not the only one i read his post on all the forums 

  As do I my friend, as do I.

 

 

[palonej]

Another vote for Ed's posted experiences!!
Not a fan of CPLs at all. Haven't had much success with them.....till I tried them in my 98!! That's all I feed her now!!
Thanks Ed!

[nced]

Good report Ed, thanks. Looking forward to see how this all works out.
   Tom

"Looking forward to see how this all works out."

I had spent the whole previous Thursday cutting up downed trees and limbs on my property from the recent ice and wind storm. I was planning to do some more property cleanup on Friday but I was pretty sore from chain sawing the previous day so I decided to drive to WV and check out my WV property for damage. Since I was going to WV I decided to take in the first DIFTA FT match of the year (it was postponed previously due to "snow on ice"). Well...I used my R9 fitted with the new style HW piston seal and it was detuned to shoot CPLs at 815 fps. The result......DOOHHHHH!!! 

At the DIFTA field target match in Damascus, MD last Saturday and I was disappointed to shoot my lowest score in YEARS! To add insult to injury.......the course setup didn't have a particularly high difficulty rating at under T30! Hummmm........think I'll blame my rotten 33/60 score on my using a factory piston seal and 11.5 fpe tune!  The issue COULDN'T have been the Nimrod behind the stock jerkin' tha trigger ya know! LOL  Actually, I'm thinking that the shooting conditions (variable wind) made the 11.5fpe setup more difficult than I expected since a while back I had my R9 tuned to 12fpe using an oring sealed piston cap instead of a factory seal and actually did really well at a match using that setup! Actually, the gun shot really sweet at "Nerf gun power" and when testing the accuracy upstairs at 18 yards before leaving it did shoot well, however I had a LOT of issues with the longer targets on Saturday! I probably would have missed a 6" diameter kill zone if it were available!

LOL.........sorry for shattering the belief that I ALWAYS have good shooting days..........but I have to admit that there are those times when MY accuracy ain't so good! 

Anywhoo.......after I got home to NC my R9 was taken apart, the piston pulled, the new style R9 piston seal was replaced with a newly turned/fitted oring sealed piston cap and the .125 wire spring was replaced with the previous 34 coil .120 wire spring. This morning I chronied the setup and was getting a CPL velocity of 870ish fps. I did some grouping upstairs last night at 18 yards and was "touching pellet holes" (usually) at 18 yards so I EXPECT that the accuracy will be good at 50 yards when I get some NC weather that's conducive to accurate shootin.
 

[chuckinohio]

  I would have thought that you had figured out a way to negate the 'Nut behind the butt' effect by now Ed................

  Shooting accurately is a perishable skill, and we all suffer from the 'Wooooopppssss'

  My comments at least, and everyone elses it seems, were based on the fact that apparently you can not or will not rest on your laurels, and are always trying something new. That something new is usually innovative, doable by almost everyone, and applicable across the board in air gunning.

  Many thanks for taking the time to share!

  P.S.
  The ranging set up with holdover markings you shared is working like a champ, as far as reference goes, but once again, the failure in the system is attributable to a shaky jake holding the rifle!!
  I waggle and bob around like a leaf in the wind!!!