Aftermarket seal odyssey!
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Aftermarket seal odyssey!
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Topic: Aftermarket seal odyssey! (Read 5597 times - 1 votes)
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mentolio
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Sharp Shooter
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Real Name: Jeff
Re: Aftermarket seal odyssey!
«
Reply #40 on:
December 09, 2017, 08:06:05 PM »
DanD: yep, I sized the seals along their entire sides, tho I will admit that I didn't measure the "base" of the seal to monitor it's size reduction. I suppose if I try this again, I will next monitor that, as well as packing the seal groove with something to reduce the amount of seal flex (at the sealing surface).
Z_Road_Inn: I suspect the END result would be much the same, whether the tube is polished or cross hatched (honed).
My understanding is that the crosshatch is merely to help the piston seal wear-in faster, and to help remove minor "blemishes" in it's surface.
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Gloucester County, NJ
If I shot half as good as you, you'd still shoot twice as good as me!
Webley Valuemax .20: airgunning's best kept secret...shhhhh!
Gut2Fish
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Real Name: Garrett
Re: Aftermarket seal odyssey!
«
Reply #41 on:
December 10, 2017, 11:45:31 AM »
Cross hatching makes for less friction. Would also allow space for lube. Not sure how much cross hatching is benefiting over the new self lubing seals. Yet to get into my gun to install a new self lube seal (purple) I'd purchased months ago from Australian Custom Seals. Think when I do I'll polish the tube with Tetra Gun L fluorapolymer and not use any moly paste.
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Vermont
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mentolio
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Sharp Shooter
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Real Name: Jeff
Re: Aftermarket seal odyssey!
«
Reply #42 on:
November 16, 2018, 06:49:24 PM »
I was reading through this old thread today and realized I had never revisited the venerable Value Max with stock seal. So I went out to shoot it and the .22 Vortexed-Vortek (Chet's gun with Vortek Piston and Vortex piston seal). I got a solid string out of the Vortek with two different pellets, but lost light before I could get to the Value Max...meh! I'll try to break away and do some velocity testing with the VMX this weekend. But what about the Vortek....?
Admittedly I haven't shot the gun much (either of them, really). I fell down the vintage pumper rabbit hole for awhile, then finally got back on a motorcycle, which kinda curtailed most airguning for a bit. Since the last installment the VMX has had maybe 2-300 pellets (at most) put through it, and had a few issues with accuracy and barrel lock-up since. All that appears to be resolved now. The Vortek I have shot significantly less, but I tested it anyway and here's how it did:
.22 Vortex sealed Vortek Piston Striker
H&N FTT 14.66gr, 5.53 head, averaged at 729.6 fps, with an extreme spread of 28.88 (yuk!) and standard deviation of 9.16.
Although I haven't been shooting this bugger much (and it still has an unresolved barrel lock-up problem), when I do shoot it I have been experimenting with other pellets (most of my guns are not huge fans of the FTTs in 5.53mm head). The FTT is not this guns favorite, and the extreme spread is from two pellets that shot slow (710 & 718, the other eight were 725 to almost 740). I did a second string with the pellet I really want to love, the H&N Terminator HP in 16gr.
H&N Terminator Hp, 16gr, averaged 697.7, Extreme spread of only 6.88, and a standard deviation of 2.44.
So this gun likes these pellets, and shoots them fairly accurately (gotta fix that darned barrel lock thingy).
Anyway on to the point: this gun has a Vortex piston seal that I resized down to 27.45 (if memory serves). While I haven't satisfactorily broken it in (meaning: not a full tin of pellets yet), it hasn't really lost or gained anything, which I consider a step in the right direction (obnoxious ES with FTTs notwithstanding). So if I find myself needing piston seals other than the factory stuff, I will be buying Vortex seals. When I fix the barrel lock-up issue, I expect to find the ES of the FTTs to go down, and the accuracy with all pellets to improve.
Ok, enough jaw-jacking. Hopefully I'll be reporting good things about the Webley this weekend.
I apologize for the long lull in this test.
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Gloucester County, NJ
If I shot half as good as you, you'd still shoot twice as good as me!
Webley Valuemax .20: airgunning's best kept secret...shhhhh!
mentolio
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Sharp Shooter
Posts: 715
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Real Name: Jeff
Re: Aftermarket seal odyssey!
«
Reply #43 on:
November 17, 2018, 11:58:47 AM »
Yet another long winded installment of the odyssey...yawn...
Ok, here are the Chrony results for the Value Max from this morning's session. First, it was a bit chilly at 43dg F. Chrony readings were taken from 1 foot from the muzzle (as I usually do). Since the last installment of "data" (sometimes it's fun talking like a smart person) I cleaned the barrel, pulling dry patches through until they stopped coming out black, no solvent. Each pellet was tested after "seasoning" the barrel with three shots in between switching pellet brands. I shot ten shot strings, with two more shots as a follow-up control group, as each string showed one to two shots (most likely due to inferior pellets) significantly lower velocity than the rest (lesson: shoot at least FIVE times between pellet brands, not just three!). Also of note: I do not sort pellets (GASP!). Nor do I wash them, or read them bedtime stories at night. I pull a pellet from the tin, shove it home, and shoot it...sometimes (sideways look at the JSBs) I inspect the skirts for damage before loading, but more often if a see a wonky skirt, I just shoot it in a safe direction and don't bother putting it over the chrony. Standard Deviation correction calculations were computed using this free online calculator (because math and science are REALLY not my thing...). On with the results!
https://www.easycalculation.com/statistics/standard-deviation.php
First up: Benjamin .20 Cylinders @ 14.3 gr. The heaviest, very accurate at 20-30 yards, fit consistency is less than stellar.
Average: 711.7. Corrected: 723.9
Extreme Spread: 88.5(?!?). Corrected: 13.8
Standard Deviation: 28.33(?!?). Corrected: 4.64
"Corrected?!? Whaddaya mean by that, cheater?!?" The second and tenth shots were ridiculously low in velocity, while the rest of the shots were very consistent (especially for a Crosman product). I didn't take notice which shots were tight in the breach, and which were loose. I only know some WERE tight, while others were loose...situation normal with most brands, but especially Crosman pellets. So I thought I would just randomly choose two more pellets and see if they were any better or worse. Both shots (11@716.7 & 12@727.5) were right in line with the other eight shots in the string. So you can take it or leave it...
Second contender: JSB Exact 13.73gr, next heaviest, not very accurate (in the past, anyway), impossible to get into the breach cleanly without a pellet seating device, which I shamelessly used here. Fit is, well, really tight.
Average: 754.2. Corrected: 755.32
Extreme Spread: 23.98. Corrected: 16.2
Standard Deviation: 6.55. Corrected: 4.91
While the extreme Spread as tested in ten shots was higher than I'd like, overall this was a good, fairly consistent string. I did the correction just because it was done on the first test. This may be my best result with these pellets, and I will make sure to test them for accuracy again.
Last contender: H&N FTT 11.42gr. The lightweight of the bunch, also the fastest, and potentially the most accurate. Overall fit was consistent/snug and easily seated by hand.
Average: 832.2. Corrected: 834.08
Extreme Spread: 14.96. Corrected: 9.3
Standard Deviation: 5.09. Corrected: 2.89
Again, only did the two-shot correction to keep things consistent. The H&Ns are not only the fastest pellets out of this gun, but are the most consistent in fit and velocity. I have no problem shooting these (or the Benjis, frankly) all day long.
"What's it all mean?" Well, not much...other than I should have used one of my other Hatsans for this test;). If we refer to my original stock readings:
Benji @ 708.9 av, 10.74 Es, 3.6 sd
JSB @ 730.7 av, 28.22 Es, 8.88 sd
H&N @ 820.3 av, 11.6 Es, 4.24 sd
...we can see that not a lot has changed from then. Overall fps are up, as are Es and Sd, but not horribly so. Remember, I liked the way this gun shot out of the box. It wasn't super crunchy like the rest of my Hatsans, and was both accurate and consistent. I decided to use this gun as my test pig because I figured there was no way I could screw it up, and that it could only stay the same or get better. What I take away from this ordeal is that somehow, the stock seal when new and PROPERLY/CAREFULLY installed (evil eye shot at Hatsan) is really the best, low cost, low effort seal for these guns. If you don't mind spending twice as much $$$ or more on a nice, perfectly round aftermarket seal that greatly cushions the harsh shot cycle, but requires a lot of experimentation to really get the most out of it, go for it! If I had the disposable income, I would buy 10 Vortek seals and size them down from their delivered size in .2-.4mm increments, all the way down to 27.4mm (any smaller and you may as well flush the money down the toilet). Then I would try each one and see which size produced the highest velocity. ARH? Great chemicals, great customer service, but not a great seal for MY Hatsan. Custom Air Seals...nope, won't do that one again either (for my Hatsans). For me it will be stock seals (and just live with the harshness) or Vortek seals (and just live with the slight loss in power).
But we're not done yet...sigh...
Going forward I plan to do a barrel swap between my VMX and Vortex Striker. Why? I want to compare the two power plants against each other. I know, one is a Vortex piston, the other is spring powered. That's why the barrel swap. I plan to examine the difference (if any) in velocity between the two guns in both calibers. The Vortex Striker is what I consider the first attempt that actually scratches the surface of success (for me), regarding the use of a Vortek seal. If the Vortex powered Striker sends .20 pellets over the Chrony at close to the same or faster fps than the spring powered VMX, it will help me determine just how successful the Vortek seal re-size is (I expect an fps deficit, but maybe I'll receive a pleasant surprise?). "Nope, it's apples and oranges, comparing the gas piston gun to a spring powered gun..." you might be thinking. That's why I will further test the .22 barrel on the VMX. The VMX acts as a control for the whole experiment. I know how fast it'll shoot .20s, and I know how fast the Striker will shoot .22s. If the VMX shoots the same .22s at a similar velocity compared to the Striker, I'll know that the power levels are in the same ballpark, and will be able to more accurately quantify my success or failure...there I go trying to sound s.m.r.t. again....
Yogi...I know it's been a while, but not yet ten years;)
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Gloucester County, NJ
If I shot half as good as you, you'd still shoot twice as good as me!
Webley Valuemax .20: airgunning's best kept secret...shhhhh!
SteveP-52
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Re: Aftermarket seal odyssey!
«
Reply #44 on:
November 17, 2018, 11:05:38 PM »
I'll have to revisit my own with the chrony since both my VMX's have had some shooting and break in time. I won't have to do any barrel swapping as one was left a springer and fully tuned, the other got a Vortex Gas ram conversion and both got brand new Vortek seals as part of their builds. If I want a control rifle, just so happens I have a 3rd VMX .20 totally untouched and bone stock. I bought 3 when Amazon was selling them off cheap
Originally there was less than a 12 fps difference between the 2 rifles so weather permitting, I'll dig the chrony out and see what happens.
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19Sheridan57
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Real Name: Steve
Re: Aftermarket seal odyssey!
«
Reply #45 on:
November 18, 2018, 07:56:00 AM »
I haven't done much testing with my VMX .20 , other than the initial testing after I got it. It was shooting about 750-820FPS, if I remember correctly, with several different weight pellets. Mine had the typical forearm break not long after owning it, so I fitted it into a Striker wood stock & added a good scope. It is a POWERFUL rifle & quite accurate . I really haven't shot it enough to break it in, yet. I hold it firmly, just like a high powered rifle. I took out a Coyote with it awhile back, that was after some young calves. " WHACK," was the sound it made when it hit his skull. I should have opened his skull & looked at the damage, but didn't . I keep this rifle close to the door in case another Coyote wants a headache.
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mentolio
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Sharp Shooter
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Real Name: Jeff
Re: Aftermarket seal odyssey!
«
Reply #46 on:
November 20, 2018, 07:38:07 PM »
Curses! Foiled again...
Just a quick update: I swapped the barrels today. My VMX has the two-piece cocking arm, my Striker Vortex has the one piece. The Striker's one-piece arm seems to work fine on the VMX power plant (as in: it cocks, locks, and fires). The VMX's two piece arm does NOT fit properly in the Vortex power plant. The Vortex Striker piston will end up hitting the cocking shoe (h-a-r-d) assuming it cocks and locks, which I didn't try. Seems the two piece cocking arm ends up just a tad longer than the one piece, which means the Vortex piston must be slightly compressed for the two piece arm to lie flat against the air tube with the piston at rest (am I making sense?).
Anyway, since the test firing of the .22 barrel on the VMX power plant seemed ok, I'll have to test the same pellets over the Chrony and just compare the results between the VMX power plant/.22 barrel/stock seal combo and the latest Chrony results of the same pellets and barrel from the Vortek piston seal equipped Striker test. Not quite as thorough as I'd like to be, but it'll have to do for now.
Although...I may still have one unmolested Vortek seal in my tool box...hmmm.........
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Gloucester County, NJ
If I shot half as good as you, you'd still shoot twice as good as me!
Webley Valuemax .20: airgunning's best kept secret...shhhhh!
SteveP-52
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Real Name: Steve
Re: Aftermarket seal odyssey!
«
Reply #47 on:
November 21, 2018, 12:48:39 AM »
The thread I posted on doing the gas ram swap to my VMX and why you ran into the issue you did with the cocking arms.
https://www.gatewaytoairguns.org/GTA/index.php?topic=129574.0
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mentolio
Follow me, I'll show you where to crash.
Sharp Shooter
Posts: 715
Ummmmm.....sure
Real Name: Jeff
Re: Aftermarket seal odyssey!
«
Reply #48 on:
November 21, 2018, 11:58:46 AM »
Thanks Steve, I knew I'd read that info here, just didn't remember where.
So I tested the .22 barrel on the Webley power plant today...to say I'm surprised is understating it a bit. First thing I noted: my barrel lock-up issue is a non-issue on the Webley action...I'll have to measure how far back the cross pins are on each gun to see if it's just another airtube defect (way to go, Hatsan!). Secondly, well...you'll see.
Webley Value Max with stock Hatsan seal, 44 degree F, five shots in between pellet changes this time.
H&N FTT 14.66gr 5.53 head: Avg- 675.9 (-54.6fps compared to the Vortek sealed Vortex piston Striker), Es- 29.59 (cut to 11.77 with two shots to replace the first two low-ball shots), Sd- 8.66 (3.31 with aforementioned two shots replaced).
H&N Terminator 16gr Hollow point: Avg- 673.2 (-24.5fps), Es- 24.6, Sd- 6.85.
Conclusion: counter intuitive! The Vortex piston power plant with a Vortek seal, sized to 27.45mm (or thereabouts...it's somewhere on page two, I think) is overpowering my factory piston sealed, spring powered Webley action in .22. This WITH a barrel that doesn't lock-up as it should! If anything, the Striker should be giving up some power to the Webley, not the other way around. Night and day difference? Not really, but significant enough to make me want to pull that last new Vortek seal out, and size it to something like 27.5mm for the Webley for a final "hoorah." Not to mention a noticeably smoother shot cycle...I only suggest going a bit larger as looking back over the initial Striker tests, the velocity has come down a tad (not a big deal), but the Es and Sd have increased significantly. So I'm thinking start the seal just a bit larger and give it some time to properly wear-in.
"Why size it then? Why not save some time and effort and just shove it in there and let it wear down to proper size?" I'm not willing to wait for 500-1000 or more shots for a seal to seal-in. If I can size it down to nearer where it will end-up, it should take a LOT FEWER shots to settle down/power-up. Also, I installed the CAS seal without sizing it, and that ended badly. Being a softer material it fit and felt nice when installed, however it eventually ended-up compressing, and lost a lot of velocity. So it seems this whole seal sizing thing is a balancing act between making it smaller but not too small (leakage, blow-by, whatever you want to call poor sealing) and leaving it to large (where perhaps it builds up too much friction, compresses, tears/chips/splits, and again seals poorly). We'll see.....
«
Last Edit: November 21, 2018, 08:10:50 PM by mentolio
»
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Gloucester County, NJ
If I shot half as good as you, you'd still shoot twice as good as me!
Webley Valuemax .20: airgunning's best kept secret...shhhhh!
mentolio
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Sharp Shooter
Posts: 715
Ummmmm.....sure
Real Name: Jeff
Re: Aftermarket seal odyssey!
«
Reply #49 on:
November 22, 2018, 02:23:41 PM »
...revisiting the Vortek seal...meh!
Pulled the VMX apart again, quick clean-out, and then installed the last Vortek seal for measurement. I decided to measure both the "leading edge" (top) of the seal diameter and the base measurement. At the top The installed diameter was 27.56mm, and at the bottom was 27.27. For this exercise I wanted to reduce the diameter to 27.50 - 27.48mm, just to leave a tiny bit extra meat on it when compared to the Vortex .22 27.45mm. So I ended up with a top measurement of 27.47mm and 26.30 at the bottom. At least I didn't exceed the .22s sizing-down.
I got it all installed with about as little lube as I've ever used on anything and went out to the garage for a twenty shot clean-out. The piston and seal went in, but felt pretty tight (tighter than I like, anyway). After twenty shots worth of Benjis, my initial feeling was that the gun was smoother, quieter, and produced zero smoke after shot #3 (and really almost no smoke prior). I then immediately set up my Chrony out back and started shootin'. It's a lot colder today than the last time I shot on the 21st, being only 28 deg F with a wind chill feeling like 14! Anyway, same pellets, same Chrony, same distance, just no 2-shot corrections...yeh, it was that bad...
Benji 14.3 cylinders: Average-643.2, Es- 23.22, Sd-7.81. If I use the "non-corrected" average from my last test, I've lost 68.5 fps! Now I know that the seal is too snug and will likely loosen up a bit as i shoot it more, but 68 fps worth of breaking in? Doubtful...
JSB 13.73 domes: Average-658.1, Es- 20.31, Sd- 6.85. Another loss, this time 96.1 fps.
H&N FTT 11.42gr domes: Average-727.8, Es- 29.88, Sd- 9.94. Minus 104.4 fps...
Sigh....what I will try to do next is just not so good it up and shoot the thing at least 20 times a day for the next week or so, then test again. I expect that as the parts loosenup and the spring tar settles, the velocity will likely increase slightly, stay the same, but more likely decrease even more. Now mind you, I wouldn't care about the velocity as much if the extreme spreads were better. If I were getting an Es in the low teens, I might not complain every time I talked about it. Extreme spreads in the single digits and I'd just leave it and call it a paper punching target gun. But a 100+fps LOSS just because I installed a new seal?!? Unacceptable.
But I digress, I'll give this seal a shot to wear-in a bit, and see how it plays out. I'm not oblivious to the fact that my airtube just may have imperfections that are invisible to my eye. Even with a stock seal, my gun sometimes seems a little low in power compared to the tests of other members (and I'm shooting at sea-level more or less). I do have an Edge that shoots really hot, and very consistent. I have considered swapping the piston assemblies and barrels and giving that airtube a go, but I really like the way that Edge shoots CPUMs, and want to hunt with it...decisions-decisions....
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Gloucester County, NJ
If I shot half as good as you, you'd still shoot twice as good as me!
Webley Valuemax .20: airgunning's best kept secret...shhhhh!
mentolio
Follow me, I'll show you where to crash.
Sharp Shooter
Posts: 715
Ummmmm.....sure
Real Name: Jeff
Re: Aftermarket seal odyssey!
«
Reply #50 on:
November 23, 2018, 04:02:40 PM »
11-23-18 gun sat overnight, decided to use it to test my "home grown" Chrony indoor lighting system...
I wasn't intending to post every time I shot this gun (you're welcome servers), but I thought this was interesting. I got to thinking today (yes, it hurt a little) that it would be nice to have the indoor light source for my Chrony, but I certainly didn't feel like spending the $$$. So I noticed these LED lights I bought at one of the home stores around here a couple years ago, remembering I almost never use them. I mounted them over my "Hobby closet" workbench to add some auxiliary lighting when my cheap-o strip light died. I really don't use them much because they are not very bright, and since replacing my main overhead light source I just haven't needed them. Anyway, 4 zip ties and 5 minutes later, I have this:
Anyway, I needed to test the light system and thought why not use the VMX. I have to shoot it anyway. So I put a quick ten shots through it over the Chrony and got these results:
Benji 14.3 cylinders: Average- 675.6, Es- 30.24, Sd-8.48.
So from yesterday my velocity increased 32.3 fps on average. In my mind, this could mean one of two things (that I can think of, anyway):
1- more consistent light equaling a better reading (which I doubt)? My understanding is that the Chrony either has enough light (functions), or it flashes errors due to to much light or insufficient light.
2- the seal has compressed a bit (being squeezed by the tube), and therefore may be sliding with less resistance?
Either way the gun has around 80 shots through it now. I was going to tear it down again and start shaving off 1/100th of a mm (or as close to that amount as I am capable of) at a time and retest. This truthfully seems the best way I can think of to size a piston seal (get it close then shave it down a tiny bit at a time until I either see readings I can live with or a drop in power). I may still do that, but am willing to shoot it some more to see if the velocity keeps coming up over time. Meantime I may order another Vortek seal or two for this gun, and maybe one or two for my Crosman NPs to start playing with them (which I should NOT do, because they both shoot really well).
«
Last Edit: November 23, 2018, 04:59:25 PM by mentolio
»
Logged
Gloucester County, NJ
If I shot half as good as you, you'd still shoot twice as good as me!
Webley Valuemax .20: airgunning's best kept secret...shhhhh!
mentolio
Follow me, I'll show you where to crash.
Sharp Shooter
Posts: 715
Ummmmm.....sure
Real Name: Jeff
Re: Aftermarket seal odyssey!
«
Reply #51 on:
November 25, 2018, 04:15:39 PM »
11-25-2018, here we go again...
So I've been shooting the Webley every day over the chrony, usually only ten shots each. What I have noticed since my initial velocity gain on the 23rd is this: while the velocity has remained a near constant 675-ish fps, the ES and SD have improved significantly. The gun went from an extreme spread of over 30 fps to 1/2 that today (ES: 15.65, SD: 5.19. Which is really a good reading for a spring gun with under 200 shots through it!). So now I have to interpret this information.
Here's what I think: I think the piston has compressed as much as it's going to, and the fit is still too tight. Sure, the seal may wear in in hundreds (more likely thousands) of shot cycles, and I may see an improvement in velocity as it does. So in short, the piston seal diameter is still too large. How big is too big? I don't know, but I'm gonna try to find out. When I disassembled the gun again, I immediately wiped the small amount of residual molly lube from its surface and measured it's diameter. The seal measured at 27.33 mm. Remember that the seal had an installed (on the piston) diameter of 27.47mm when I was done sizing it the first time. So I know the piston seal is compressing AT LEAST .14mm, likely a bit more. After approximately 10 minutes outside the airtube, the seal expanded to 27.40mm.
Here's the plan: I'll let the piston seal sit "at rest" overnight, and when I get home from work tomorrow I will re-measure the diameter. While I don't expect it to expand to it's full 27.47mm diameter (or more...THAT would be weird!), I suspect it will expand a bit more than it already has. Once I'm confident that it is done expanding, I'll start sizing it down (slightly) and retesting. So my first target number will be somewhere right around 27.45mm, same as the Striker seal. If (hopefully) I see an increase in velocity, I'll decide where to go from there based on how big an increase, if any (if I see a decrease then this exercise is likely over, at least for the Webley). Having learned that I have to leave the seal in the gun at least overnight to allow it to compress a bit, I will certainly repeat that process. I'll test after twenty "clean-out" shots, then will test over the next several days to see how it goes. If velocity increases to 700fps or more (which I KNOW this gun is capable of), then I'll let it ride and see how it breaks in. If the increase is minimal (say 680-690fps), I'll try reducing diameter by hundredths of a millimeter (which is likely not very likely for me to accurately do, but I'll try). Once I am satisfied with the seal performance I also want to try sleeving the piston, which if I understand correctly should nearly negate the need for Heavy Tar on the spring, and make the gun "twang-free" (which it is now, but in a few hundred shots will likely start to buzz a bit). I won't do the sleeve until I know the seal is doing what I need it to. Ok, wish me luck!
«
Last Edit: November 25, 2018, 04:49:49 PM by mentolio
»
Logged
Gloucester County, NJ
If I shot half as good as you, you'd still shoot twice as good as me!
Webley Valuemax .20: airgunning's best kept secret...shhhhh!
SteveP-52
I just lurk, I'm no longer a
GTA Senior Contributor
Posts: 8002
Real Name: Steve
Re: Aftermarket seal odyssey!
«
Reply #52 on:
November 25, 2018, 09:36:26 PM »
Don't know if this will help you any, but my springer is sleeved and no heavy tar on the spring although I did rub a light coat of moly on it and there's no spring twang. Just make sure it slides inside the piston far enough not to block the slot the lower sear drops into.
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NY, USA
mentolio
Follow me, I'll show you where to crash.
Sharp Shooter
Posts: 715
Ummmmm.....sure
Real Name: Jeff
Re: Aftermarket seal odyssey!
«
Reply #53 on:
November 26, 2018, 05:57:03 PM »
Will do Steve, thanks!
11/27-2018
Measured the piston seal when I got home, and it has expanded to only 27.43mm. Won't have time to play with it tonight, so that seal will get another 24 hours to "get right." If by tomorrow it hasn't yet expended fully, I'll have to assume it won't, and adjust my plan from there. Assuming the diameter does not change from today's measurement, I'm thinking I'll likely aim for 27.40mm and try again. Only problem will be that if it doesn't expand to its full 27.47mm, whatever measurement I end up with that actually works (meaning velocity of at least 700fps with the Benji cyls) will likely not be an accurate measurement for future attempts, due to the fact I can't quantify how much of my missing seal diameter is due to wear vs. compression. Meh...if I can get it to work it'll give us a "ballpark" to aim for, I suppose.
Logged
Gloucester County, NJ
If I shot half as good as you, you'd still shoot twice as good as me!
Webley Valuemax .20: airgunning's best kept secret...shhhhh!
Yogi
GTA Senior Contributor
Posts: 7439
yes
Real Name: Yogi
Re: Aftermarket seal odyssey!
«
Reply #54 on:
November 26, 2018, 07:14:42 PM »
mentolio
They say the piston seal is properly sized when you can push the piston down with your finger and about 2 lbs of force.
No need to put it all back together again just to crony it.
-Y
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San Francisco, CA
Hatsan 95 Vortex, .22
RWS 5G,
Diana 10M
RWS LP8 Magnum,
Diana 340 N-Tec, .22 Compact Lexus
HW 50S, .177, .20, and .22
Mossonarock
Licensed to crenellate
Sharp Shooter
Posts: 859
~~~
Real Name: Tim
Re: Aftermarket seal odyssey!
«
Reply #55 on:
November 27, 2018, 05:02:29 PM »
Yogi,
If what you say is true, then my OEM Hatsan piston seals I bought for my Dominator and Edge are way too big.
I nearly had to hammer the piston in.
How would one reduce the diameter of a piston seal without having access to a lathe?
I suspect there's a drawing board in my future that I need to revisit.
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USA, NC, Winston-Salem
Negative Golden Rule: Do not do unto others what you do not want done unto you.
mentolio
Follow me, I'll show you where to crash.
Sharp Shooter
Posts: 715
Ummmmm.....sure
Real Name: Jeff
Re: Aftermarket seal odyssey!
«
Reply #56 on:
November 29, 2018, 08:22:00 PM »
11/29/18
Two days ago the seal ended up returning to not quite it's "installed size" of 27.47. It never expanded past 27.43mm (that's a LOT of squeezing!). Hmmm, .04mm smaller...how much of that was from wear, and how much of that was compression that just didn't come back. Man, I don't know! I decided to size it down to 27.37mm. My reasoning being that about a year ago when I did the first set of tests for this brand of seal, I sized it to 27.27mm and got very nearly 700 fps with the Benji pellets (was in the 690s with a sub 30 extreme spread, which may have shaped-up to be just about ideal). Not wanting to miss the mark by a narrow margin, I opted for .10mm larger @ 27.37mm. I can always go smaller, but there's no getting bigger once the material is removed.
Anyway, at 27.37 the fitment was a lot easier, but still more than two pounds of pressure. Initial testing yielded similar velocity: Average- 674.0, Es- 15.19, Sd- 4.84. So, not really any gain in velocity but much better Es and Sd to start. So I hoped that letting it sit overnight might yield an increase similar to what I experienced on day two of the seal being installed at 27.47mm. Meh, no such luck. Day two yielded similar results all around with the Benjis, and when I tried the JSBs and H&Ns I was similarly unimpressed. The JSBs were faster with an Es that was just under 20fps, and the H&Ns were all over the place. I didn't waste any pellets "seasoning" in between changing brands, as I doubt it would have made any significant difference.
Ok...you may be wondering: "what's the big deal?!? The gun shoots a bit slow, but is in that sub-1% standard deviation magic zone...why not just leave it?" Yes, I'm certain the gun is as accurate as it's ever been, which is to say bloody-accurate for a 100 dollar gun. It's always been very accurate, even when my Chrony numbers were significantly worse. The goal I'm trying to achieve is to find out how high I can get the velocity to go with an aftermarket seal vs. what I know the gun will do with a stock seal. I know this gun will send Benjis at almost 720fps with a stocker in it, and the stocker is really garbage compared to the aftermarket seal build quality (if not function, so far). So...this aftermarket seal should be able to match or exceed the stocker's ability to "go fast." And once I find out what size it needs to be to do that, I'll share that info with the group...win-win!
So next...not forgetting that my best velocity results with this brand of seal were at an installed measurement of 27.27-ish mm. So I'll give this seal another couple strings over the Chrony, and if there is no noticeable increase, I'll take it down some more. Depending on what diameter the seal comes out at, I'll likely downsize to just over 27.30mm. If I see no increase, I'll start suspecting I've missed the mark again. If I see a decrease, we'll that will remove all doubt, and I'll shove another stocker in there until I can score more Vortek seals.
Logged
Gloucester County, NJ
If I shot half as good as you, you'd still shoot twice as good as me!
Webley Valuemax .20: airgunning's best kept secret...shhhhh!
mentolio
Follow me, I'll show you where to crash.
Sharp Shooter
Posts: 715
Ummmmm.....sure
Real Name: Jeff
Re: Aftermarket seal odyssey!
«
Reply #57 on:
November 29, 2018, 08:28:37 PM »
Mossonarock: I use a bit of an old broken brake cylinder hone and some rubber hose to chuck the piston, with seal installed, in my drill press. With some careful adjustment I get it spinning fairly true, then go to work on the side/sealing surface with a popsicle stick and 400 grit sandpaper. I would suggest NOT sizing the stock seal. Every one I have installed felt like it took A LOT more than 2 pounds of pressure to get it home, but they yield good velocity results if not damaged upon install. I'll try to post a picture tomorrow.
Actually, now that I said that, perhaps sizing a stock seal would increase performance? Hmmm.....
«
Last Edit: November 30, 2018, 05:44:25 PM by mentolio
»
Logged
Gloucester County, NJ
If I shot half as good as you, you'd still shoot twice as good as me!
Webley Valuemax .20: airgunning's best kept secret...shhhhh!
RBQChicken
Expert
Posts: 1648
Real Name: Randy
Re: Aftermarket seal odyssey!
«
Reply #58 on:
November 29, 2018, 08:55:43 PM »
I've been following this thread for quite awhile, but now I don't remember why you don't want to use the stock seal if it gives you the most speed you've ever got with this gun? Was it erratic patterns?
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U.P. of MI
The first time I hit it, I missed. The second time I hit it in the same place.
mentolio
Follow me, I'll show you where to crash.
Sharp Shooter
Posts: 715
Ummmmm.....sure
Real Name: Jeff
Re: Aftermarket seal odyssey!
«
Reply #59 on:
November 30, 2018, 07:32:32 AM »
I guess the reason for this thread has evolved somewhat. Originally I wanted to see which of the most talked about seals actually produced. There are nearly countless posts online that tout the superiority of the aftermarket seal, but very few posts actually use Chrony data to prove it (and maybe my research is lacking, but I don't believe ANY of the manufacturers of these seals offer any promises regarding the power potential of their products, other than a general "it's better than stock"). "It feels better, smoother, and more powerful," is the general claim. I just wanted to quantify improvements over stock, if there were any, and if not maybe call attention to the fact that not everything that claims to be "better" is. I worked as a motorcycle mechanic in the 90s, and ran the Dyno room at one of the dealerships where I worked. While learning to properly utilize the dynamometer the most important thing I learned was that 60-70% of the supposed "performance upgrade" parts on the market (at the time) did NOTHING to improve performance. "It feels better, smoother, and more powerful," was said by every person that spent a small fortune on a bunch of aftermarket stuff for their bike (and every sport bike squid EVER after installing a slip-on!). Most of the stuff had reduced weight over stock, or made a little more noise, but did not positively effect the bike's horsepower at all. I wondered if the airgun aftermarket had the same problem?
Now I'm picking the most likely subject to succeed (in my opinion, the Vortek seal), and just trying to see: A-what it takes to grab success and B-quantify with hard facts just what the upper threshold of success looks like with this seal. Lastly, I'm learning (hopefully/maybe not) how to properly size a seal not just for this gun but for any gun. In the end will I have a stock seal in the gun? Maybe, but I'm hoping that I can figure out how to optimize this Vortek seal, which on the surface should be superior to the stocker in every way.
Edit: sorry Randy, I didn't really answer your question. This gun always shot tight groups, it was just getting twangy/buzzy/bangy and so I decided to tear it down and give it the treatment. i had just done my Mod 85 with an ARH seal, and was really disappointed with the results. Knowing this gun was capable of tight groups, low Es and Sd, and decent power (Av 710-ish fps with Benjis as stock), I felt it was the ideal test pig for the odyssey.
«
Last Edit: November 30, 2018, 07:45:26 AM by mentolio
»
Logged
Gloucester County, NJ
If I shot half as good as you, you'd still shoot twice as good as me!
Webley Valuemax .20: airgunning's best kept secret...shhhhh!
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Aftermarket seal odyssey!