I just received my new HW95 piston from Specialty Shooting Sports

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and it's pretty interesting the difference between this piston and the one that came with my newest R9 bought a couple years ago. Here are a couple pics........


The first thing I noticed was that this piston came with the new style piston seal which uses a rather thick parachute edge rather than the thin parachute edge of the old style seal. The face of the new seal is also different in the sense that the face is "dished" a bit which reminds me of some aftermarket seals I've seen. Here is a pic showing the evolution of some HW piston seals over the years...........


I also noted that the piston came with a piston liner like those of years ago. The piston that came with my latest R9 bought a couple years ago was "linerless" so perhaps HW had second thoughts concerning the linerless piston.

Anywhoo.....I had modified the original piston that came with the latest R9, lightening it with machining, and then adding buttons to the piston skirt, and adding an oring sealed piston cap. Well.....I noticed when doing the buttoning that the piston to receiver fit of the piston was very good in the first place so after doing the buttoning operation I even wondered if it was worth the effort. My intentions for the new piston which cost less than $45 including shipping, piston seal and liner is to simply polish the piston skirt and use "as-is" to get a feel for how it compares with my altered and oring sealed piston.

It's cold outside and inside my workshop/garage so I thought I'd just post this fyi!

[fperez0209]

Hey Ed,Thanks for posting.Do you have a link to Specialty Shooting Sports.Thanks in advance,   Felix

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Re-assembled my .177 R9 last night with the new HW95 piston I received from Specialty Shooting Sports using Krytox GPL 105 OIL for lube and just chronied a few shots. The exact same .120 wire 33 coil after market spring fitted to a tight Delrin spring guide and top hat that was giving me a CPL velocity of 880fps with the oring sealed piston cap.

Well.....the CPL velocity with the new style HW piston seal was 910fps and the shot cycle was really nice and not as sharp as when I had the oring sealed piston cap fitted! The velocity gain I got with a "less sharp" shot cycle was a real surprise to me since I've ALWAYS had about a 20-30fps velocity drop using a "parachute seal".

Anywhoo.....now the testing begins concerning the consistency of the poi when the weather improves for shootin! If the performance holds up with the new style factory seal, then I'll dispense with the tedious cutting of aluminum oring sealed piston caps!

[nced]

Hey Ed,Thanks for posting.Do you have a link to Specialty Shooting Sports.Thanks in advance,   Felix

Yep....here it is..........
http://www.specialtyshootingsportsoutdoors.com/
They are a reliable Canadian retailer that I've used before.
The funny thing is that the package was sent to via USPS flat rate which only cost $5.50 to send to NC from Canada. A really nice thing is that after placing the online order I got an email stating the shipping charges for approval BEFORE shipping! A really nice touch! LOL.....I went to the Honda site to order a single crank shaft pulley mounting bolt and they wanted $9 just for shipping!

[HYspd]

well..they do have to pay the monkey to pack the box...I know it's just bananas, but it is winter in the north hemisphere

[stija]

So if i am to understand this correctly, the same rifle with a new piston and seal shoots a bit faster than when it had the tuned piston in there?

Also, how many years difference in age are talking about when you compared those three different seals? I am asking because the pictures actually evidence that someone at HW is tinkering with the seals and changing them, and i am wondering how often does that just happen.  Every 5 or every 20 years, or more.

But keep us posted, i would be interested to find out how the OE HW piston compares to your tuned piston over some time.  Interesting results though. What is the spread like, or the consistency in FPS with this new setup?

Also, what made you just purchase a new piston and seal?  Pure curiosity to compare to your setup?

[nced]

So if i am to understand this correctly, the same rifle with a new piston and seal shoots a bit faster than when it had the tuned piston in there?

Also, how many years difference in age are talking about when you compared those three different seals? I am asking because the pictures actually evidence that someone at HW is tinkering with the seals and changing them, and i am wondering how often does that just happen.  Every 5 or every 20 years, or more.

But keep us posted, i would be interested to find out how the OE HW piston compares to your tuned piston over some time.  Interesting results though. What is the spread like, or the consistency in FPS with this new setup?

Also, what made you just purchase a new piston and seal?  Pure curiosity to compare to your setup?

To Clarify........
I machined the original piston that came with the gun to make it lighter for use as a 12fpe springer last year with an oring sealed piston cap. I later "upped" the velocity of my .177 R9 simply because the aftermarket spring I was using broke after a few years and 10s of thousands of shots since the spring was previously used in a different R9 and was taken from my "used parts bin". Due to the breaking of the spring used for the 12fpe setup the only .120 wire spring I had left was installed and with that specific spring along with the lightened piston and oring sealed piston cap the lowest CPL velocity I could get was 880 fps without clipping a coil or two.

When I installed the new unmodified piston and piston seal, shot some groups last night, then chronied the gun this morning I got a CPL velocity of 910fps plus or minus a few.

Anywhoo......you do make a good point by pointing out that the "880 fps piston and piston cap" were indeed different in the sense that the new piston is unbuttoned and has a new style factory HW seal.

As far as WHEN the R9 changes were made....I really don't know since The last R9 I bought came from Straight Shooters around June of 2012. I do know that my current R9 came with some new features like bolt on stock mounting bracket instead of welded tabs, the cocking shoe no longer rode on a piston liner but on the edges of the cocking shoe slot, plus the piston didn't have a piston liner which all previous R9s I bought used. This R9 did however have the old style piston seal which had a thin parachute sealing edge rather than a thick edged parachute seal. The new HW95/98 piston came with a piston liner and latest piston seal like that in the HW97 I recently tuned for a fellow. The piston seal that came with the new piston looked like the seal I removed from the HW97...........


Anywhoo.....I personally LIKE the changes HW made to the internals of my newest R9 and I feel that HW is making the changes to improve the R9 rather than makinjg cost cutting changes!

I really don't know what the velocity of my newest R9 was before I modified it since I simply disassembled the gun and did my mods before shooting over a chrony. I do know that when I USED to chrony a new R9 when I received it the CPL velocities ranged from 850-870fps in factory trim (most about 860fps) after a few dozen "clearing shots". Never had I owned a new .177 R9 shoot CPLs at 910fps so I assumed that the increase was due to the better design of the new piston seal. LOL.....previously I have NEVER had a factory (or after market) piston seal exceed the velocity of a fitted oring sealed piston cap! 

[stija]

I am shooting a HW95 (R9) .177 bought from AoA just before the end of year.  I installed a vortek pg2 kit because it was twangy.  They chronied mine infront of me before i took it home and they gave me a receipt-like printout, at which i must have looked but have since misplaced.

Mine came with the same OE seal that your HW97 came with. I attached the pics.  Also while inspecting the parts now, i noticed that there is a shim on top of the spring that i dont remember seeing at all.  Was i supposed to leave it inside the piston on top of the PG2 Vortek spring?  I attached the pic of the shim that i am speaking of and its OE location on top of the OE spring. 

I dont recall seeing or addressing this issue, and i assume that the shim must have stuck to the spring because of grease/lubricant and came out without me noticing it.  I really hope i dont have to open and tinker with my gun as it shoots fine.  But if it is supposed to be inside on top of the PG2 Vortek spring then i am willing to open it (for an inspection hahaha) and put it where it needs to be.

EDIT: I just visited PG2 Vortek Kit website at http://vortekproducts.com/ourstore/HW95PG2 and they have a top guide on the spring. So i may have asked a ridiculous question because i forgot the PG2 spring setup with the top guide of some sort (plastic or metal).