GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: drummerboy7816 on November 19, 2017, 05:41:26 PM
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Just did the bstaley mod with 4 #211 o rings (the o ring sizes are confusing as most say use 113 but the 211 I got from Home Depot are a perfect fix inside the barrel of my Prod). Greased coated them so they shouldn't be moving around . Also added a heavier spring (.30 diameter, 1.5", 0.42) and opened the TP using a 1/8" drillbit.
The problem I'm having is that when I tried with 3 o rings, even when HS and HT is at full CCW, when I pull he tirgger, it lets it a "farting" of air, buzzy sounding, and uses up a whole bunch of air. It's as if the value is stuck open for longer then it should for some reason. Switched to 4 o rings and it's better in that it doesn't happen right off the bat, however, it still happens in certain settings of HT or HS.. sometimes it happens right off the bat in the new setting, but often it happens only when I hit a lower PSI (like under 1,500).
I'm able to get a pretty decent tune avg 21 FPE using 18g pellets for 16 shots with 6% ES, but having trouble dialing in a setting with 16FPE avg for 24 shots without it farting out sometimes.
Any idea what's happening and how to fix it? Thanks in advance!
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Just did the bstaley mod with 4 #211 o rings (the o ring sizes are confusing as most say use 113 but the 211 I got from Home Depot are a perfect fix inside the barrel of my Prod). Greased coated them so they shouldn't be moving around . Also added a heavier spring (.30 diameter, 1.5", 0.42) and opened the TP using a 1/8" drillbit.
The problem I'm having is that when I tried with 3 o rings, even when HS and HT is at full CCW, when I pull he tirgger, it lets it a "farting" of air, buzzy sounding, and uses up a whole bunch of air. It's as if the value is stuck open for longer then it should for some reason. Switched to 4 o rings and it's better in that it doesn't happen right off the bat, however, it still happens in certain settings of HT or HS.. sometimes it happens right off the bat in the new setting, but often it happens only when I hit a lower PSI (like under 1,500).
I'm able to get a pretty decent tune avg 21 FPE using 18g pellets for 16 shots with 6% ES, but having trouble dialing in a setting with 16FPE avg for 24 shots without it farting out sometimes.
Any idea what's happening and how to fix it? Thanks in advance!
First, Ben, I know you are not putting the Bstaly o-rings in your barrel.
You are putting them ahead of your hammer.
With your spring and hammer fully CCW the gun should not fire.
Turn your hammer (HT) Cw until it does.
Then turn HS CW to get the speed you want.
I have the four o-ring mod on mt 1720T but the spring I use is a bit lighter than yours:
.300X.041X.5
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Hammer bounce.
I looked at #211 o-ring and they should not fit, larger diameter and larger cross section. I suspect you have something different. Do you have ID and cross-section measurements?
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Just did the bstaley mod with 4 #211 o rings (the o ring sizes are confusing as most say use 113 but the 211 I got from Home Depot are a perfect fix inside the barrel of my Prod). Greased coated them so they shouldn't be moving around . Also added a heavier spring (.30 diameter, 1.5", 0.42) and opened the TP using a 1/8" drillbit.
The problem I'm having is that when I tried with 3 o rings, even when HS and HT is at full CCW, when I pull he tirgger, it lets it a "farting" of air, buzzy sounding, and uses up a whole bunch of air. It's as if the value is stuck open for longer then it should for some reason. Switched to 4 o rings and it's better in that it doesn't happen right off the bat, however, it still happens in certain settings of HT or HS.. sometimes it happens right off the bat in the new setting, but often it happens only when I hit a lower PSI (like under 1,500).
I'm able to get a pretty decent tune avg 21 FPE using 18g pellets for 16 shots with 6% ES, but having trouble dialing in a setting with 16FPE avg for 24 shots without it farting out sometimes.
Any idea what's happening and how to fix it? Thanks in advance!
First, Ben, I know you are not putting the Bstaly o-rings in your barrel.
You are putting them ahead of your hammer.
With your spring and hammer fully CCW the gun should not fire.
Turn your hammer (HT) Cw until it does.
Then turn HS CW to get the speed you want.
I have the four o-ring mod on mt 1720T but the spring I use is a bit lighter than yours:
.300X.041X.5
Thanks. You're correct, i meant in front of he hammer, not in the barrel.
Interesting, I thought I read the opposite with HT and HS (ie use HT to control desired speed once minimum is reached with spring), I'll give this way a go!
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Hammer bounce.
I looked at #211 o-ring and they should not fit, larger diameter and larger cross section. I suspect you have something different. Do you have ID and cross-section measurements?
Ah.. I thought bstaley in a way helps with hammer bounce?
I thought the 211 shouldn't fit either, but the diameters in the one I bought from Home Depot looks like the 113 so I got it, and i truely cant imagine a better fitting ring. Picture of the ring package attached.
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Hammer bounce.
I looked at #211 o-ring and they should not fit, larger diameter and larger cross section. I suspect you have something different. Do you have ID and cross-section measurements?
Ah.. I thought bstaley in a way helps with hammer bounce?
I thought the 211 shouldn't fit either, but the diameters in the one I bought from Home Depot looks like the 113 so I got it, and i truely cant imagine a better fitting ring. Picture of the ring package attached.
The physical size on the package matches the nominal for a 113 o-ring. My guess is they are 70D but not indicated.
For your 24@16fpe tune,, what is the throw and hammer spring adjusters set to?
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Those dimensions are precisely a -113 O-ring. Absurd that they'd label it a 211. That must be their part number, and what a terrible choice because it is a valid AS568 "dash" number.
But yeah, a bstaley O-ring buffer will help prevent hammer bounce when configured correctly.
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A minor thread derailment...
Has anyone, besides me, removed the flange from the striker and recessed it about .030 - .050". Seems like you wouldn't need so many O-rings. Or, you could use a SSS as a slingshot setup... works exceptionally well with the drop-sear drag.
Does anyone know what happened to BStaley? He documented this o-ring mod six years ago and then dropped off the planet about a year later... nice guy, enjoyed his posts.
Okay, carry on ;D
Wyo
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So I tried the starting with full CCW as suggested and turned the HT only enough to engage a shot then a tiny bit more (0.75 CW), then slowly turned up the HS with did slowly increase the velocity (maxed out at 7.5 turns), that yielded me a FPS around 600 at 2,800 PSI (using 18.13g pellets, 14.5 FPE). Here are the results:
# FPS FPE PSI
1 601 14.5 2800
2 601 14.5
3 588 13.9
4 592 14.1
5 590 14.0
6 590 14.0
7 584 13.7
8 586 13.8
9 592 14.1 2500
10 586 13.8
11 584 13.7
12 586 13.8
13 584 13.7
14 586 13.8 2400
15 582 13.6
16 582 13.6
17 580 13.5
18 584 13.7 2300
19 573 13.2
20 571 13.1
21 570 13.1 2100
22 575 13.3
23 573 13.2 2000
24 577 13.4
25 575 13.3
26 567 12.9
27 552 12.3
28 566 12.9
29 558 12.5 1900
30 565 12.9
31 564 12.8
32 562 12.7 1900
ES 8.7%; however, if you take out the first 2 and that one outlier, it's under 4%. I'm wondering if a heavier spring would help bring me to an acceptable ES at 16 FPE for 3 clips.
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I'm wondering if o ring hardness has to do with it too, mine seems decently soft and can imagine the hammer bouncing off it on low pressure.
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I would recommend starting out with a few turns on the hammer spring for more consistent hammer strikes. I would also recommend starting out in the middle of your desired fill pressure to expose the peak of the future string. I would also start out with an empty chamber and gradually increase the flush striker CW while shooting until you start hearing a decent amount of air coming out of the muzzle end. At that point I would refill back to mid pressure, load pellets and shoot over a chrono while adjusting the striker CW in very small increments to the point where the velocity rises to the max velocity and then begins to drop while staying very close to the middle of your desired fill pressure. This drop in velocity will tell you that you have come off of the O-rings and need to adjust the striker CCW to get back on them. At that point I would do a full fill and run a full string. If you need to make velocity adjustments after reviewing the full string I would only make fine adjustments to the striker in a CCW fashion or very slight hammer spring adjustments to correct the string results. A small change to the striker makes a big change in velocity and you want to stay within the hammer striking the O-rings and not bypassing that action and be back to just the striker striking the valve. Hopefully that makes sense. I would also recommend burnishing the O-rings with silicon grease to help them stay together and be more consistent. This will help your ES results too.
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A minor thread derailment...
Has anyone, besides me, removed the flange from the striker and recessed it about .030 - .050". Seems like you wouldn't need so many O-rings. Or, you could use a SSS as a slingshot setup... works exceptionally well with the drop-sear drag.
Does anyone know what happened to BStaley? He documented this o-ring mod six years ago and then dropped off the planet about a year later... nice guy, enjoyed his posts.
The head of the striker is about the same thickness of a 113 o-ring. You could remove the head and save an o-ring. I have used a set-screw to get more hammer throw (non-BSB tune). You loose the positive stop at full CCW, which would be problematic on a BSB tune. ie the throw adjustment is critical and sensitive, and having a positive reference is a good thing.
I shim my O-rings to keep the throw adjustment within one full turn from full CCW. I use about 2/3 of a 113 o-ring thickness for the 16fpe tune, with 3 o-rings.
I haven't seen any posts from him in a very long time. I too enjoyed his posts and comments. Many an o-ring has been sold on ebay using his name, but not by him.
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I'm wondering if o ring hardness has to do with it too, mine seems decently soft and can imagine the hammer bouncing off it on low pressure.
A soft o-ring would be 50D, and they cost more than the standard 70D. I have tried 90D (hard) in a BSB, but had more erratic Es. IM me your address and can toss some 113 o-rings in an envelope for you.
You are using a spring that is probably equivalent to what I use. I typically only open the TP to 0.110" vs the 0.125" you are using. Should just mean less adjustment on throw for same power, but more sensitive to adjustment. I don't think that is causing the farting, but releases more air on each bounce.
My tunes are generally 3k to 2k, and don't shoot them down as low as you have. The lower the pressure, the easier it is to open the poppet on a hammer bounce.
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So I tried the starting with full CCW as suggested and turned the HT only enough to engage a shot then a tiny bit more (0.75 CW), then slowly turned up the HS with did slowly increase the velocity (maxed out at 7.5 turns), that yielded me a FPS around 600 at 2,800 PSI (using 18.13g pellets, 14.5 FPE). Here are the results:
# FPS FPE PSI
1 601 14.5 2800
2 601 14.5
3 588 13.9
4 592 14.1
5 590 14.0
6 590 14.0
7 584 13.7
8 586 13.8
9 592 14.1 2500
10 586 13.8
11 584 13.7
12 586 13.8
13 584 13.7
14 586 13.8 2400
15 582 13.6
16 582 13.6
17 580 13.5
18 584 13.7 2300
19 573 13.2
20 571 13.1
21 570 13.1 2100
22 575 13.3
23 573 13.2 2000
24 577 13.4
25 575 13.3
26 567 12.9
27 552 12.3
28 566 12.9
29 558 12.5 1900
30 565 12.9
31 564 12.8
32 562 12.7 1900
ES 8.7%; however, if you take out the first 2 and that one outlier, it's under 4%. I'm wondering if a heavier spring would help bring me to an acceptable ES at 16 FPE for 3 clips.
You don't need a heavier spring. Go to 1 turn on throw, and try again. My guess is the sweet spot in the throw is somewhere from 1 to 1.5 T from CCW for you.
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Thanks for all the great info and O ring offer John! Ill PM you my address shortly.
I did actually try various turns at 25% increments (maybe I need to try smaller increments) of the HT at good PSI range (2400 - 2600) and here's what I got:
1 turn: 612 FPS, 15 FPE
1.25 turn: 642 FPS, 16.6 FPE
1.5 turn: 672 FPS, 18.2 FPE
1.75 turn: 701 FPS, 19.8 FPE
2 turn: 740 FPS, 22 FPE
I would be very happy with those numbers if I could get <4% ES and no hammer bounce farting.. but I found that even at 1 turn, I was starting to notice a bit farting and progressively worse with more CW turns. The highest turns without any farting was at 0.75 turns, which is when I ran the full string above, but obviously less than ideal FPS. Wondering if it's really the o rings being too soft (the package doesn't indicate hardness).
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I'm wondering if o ring hardness has to do with it too, mine seems decently soft and can imagine the hammer bouncing off it on low pressure.
A soft o-ring would be 50D, and they cost more than the standard 70D. I have tried 90D (hard) in a BSB, but had more erratic Es. IM me your address and can toss some 113 o-rings in an envelope for you.
You are using a spring that is probably equivalent to what I use. I typically only open the TP to 0.110" vs the 0.125" you are using. Should just mean less adjustment on throw for same power, but more sensitive to adjustment. I don't think that is causing the farting, but releases more air on each bounce.
My tunes are generally 3k to 2k, and don't shoot them down as low as you have. The lower the pressure, the easier it is to open the poppet on a hammer bounce.
I did order a 0.105 TP from Hillairguns yesterday too just to have for lower tunes which sounds like is what I want to use for a 16 FPE 24 string over my current 0.125 TP?
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Why some act like that and others don't...just is.
See your issue...it's not that you haven't found a no bonce/no fart setting, but that you don't like the energy when it's not bouncing.
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Why some act like that and others don't...just is.
See your issue...it's not that you haven't found a no bonce/no fart setting, but that you don't like the energy when it's not bouncing.
Why some act like that and others don't...just is.
See your issue...it's not that you haven't found a no bonce/no fart setting, but that you don't like the energy when it's not bouncing.
Right, I would be pretty happy with the ES of the 32 shot string (minus the outlier which could be just &^^& pellet) if that was at 16 FPE even at 24 shots.
In reading the original Bstaley long notes, and I think it's what Keith above was saying, I'm going to try the route of finding the HT sweet spot at a lower spring tension first and making micro adjusting from there using the HT for velocity (oppose to me maxing out on HS and barely any HT). I looked at an older string I had and I think this is a good place to start, which is using HT and HS at 3.5 from CCW. If you shave off the last 3 shots (and possibly replace with higher PSI starting at 3000 instead of 2800), it's at 3.2% ES. Thinking turning HT a quarter or half turn more would get me to around 16 PTE goal (fingers crossed no farting).
# FPS FPE PSI
1 588 13.9 2800
2 594 14.2
3 592 14.1
4 599 14.4
5 601 14.5
6 601 14.5
7 605 14.7
8 603 14.6 2400
9 603 14.6
10 605 14.7
11 605 14.7 2200
12 603 14.6
13 601 14.5
14 599 14.4
15 599 14.4 2000
16 601 14.5
17 599 14.4
18 586 13.8
19 599 14.4
20 588 13.9
21 586 13.8 1700
22 567 13.0
23 567 13.0
24 561 12.7
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Don't know...never was happy with the o-ring mod in the P-Rod...and I don't give up easy. Remember trying that mod on maybe 5 or 6 airguns (mostly crosmans) and finding a couple that just didn't want to get with it...figured my P-Rod was one of "those".
Wish you better luck....not just getting it where you want it, but having it stay there.
Know that as-issued, have tuend it several ways, and could find 24 shots inside of 4%. Some times it was as low as 14.3foot pounds, sometimes as high as 15.3 foot pounds. Could certainly make it shoot faster/more energy, but always ended up kind of "balanced" at the same energy level in order to get 24 shots.
Considering the mags hold 8 and this gets mostly used out in the woods, figure having the shot count stop in multiples of mag. size (8) made sense to me. So 16, 24, or 32 shots seemed like good places to tune for.
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Thanks. It's a good thing I do enjoy the scientific process :) I bought some vibra-tite to toughen up the adjustments, hopefully that'll keep it in tune once I get the settings sorted out. My goal is to have it set up 20 PFE for 16 shots, 16 FPE 24 shots, and some absurd shot count for like 10-12FPE plinking, just by adjusting the HT and all under 4% ES. That would be success for me.
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That's the way....clear goals keep you from getting side tracked. Do think you can manage those shot counts and stay under 4% varation doing it. Using the o-ring mod might help....but think you might have to change the stack height (or hardness).
Actually, think with enough experimentation (not modification....but a careful, recorded adjustment of adjustments) could manage the goals without the O-rings.
I could "cheat" and feed the thing 18- 21gr. pellets. Same setting that manages 15foot pounds with 14.3gr. will make 16 foot pounds with 18-21gr. pellets....and usually ad one or two shots to the 4% shot count.
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So I think I'm starting to get a hang of this thing.. Starting 3,000 PSI, I'm finding to get my sweet spot starting at that range, my spring needed to be at around 5 turns CW, then I start messing with the HT for velocity. Here's a sweet string for around 12.5 FPE (1 HT, 5 HS):
# FPS FPE PSI
1 559 12.58280146 3000
2 554 12.35871331
3 556 12.44810697
4 556 12.44810697
5 565 12.85436489
6 556 12.44810697
7 560 12.6278607
8 560 12.6278607
9 565 12.85436489
10 556 12.44810697
11 560 12.6278607
12 566 12.89990734
13 562 12.71822077
14 554 12.35871331
15 558 12.53782276
16 564 12.80890299
17 558 12.53782276 2300
18 554 12.35871331
19 560 12.6278607
20 564 12.80890299
21 566 12.89990734
22 561 12.67300047
23 558 12.53782276
24 562 12.71822077 2000
24 shots @ 2.1% ES, pretty nice, should of gone longer to see how low it will go but I stopped. Using this, I tried again at the 16 FPE (1.40 HT, 5 HS):
# FPS FPE PSI
1 624 15.67916418 3000
2 630 15.98213619
3 624 15.67916418
4 631 16.0329134
5 631 16.0329134 2800
6 628 15.88082338
7 633 16.13470942
8 636 16.28800746
9 633 16.13470942
10 630 15.98213619 2500
11 626 15.77983271
12 628 15.88082338
13 626 15.77983271
14 626 15.77983271 2300
15 626 15.77983271
16 619 15.42890221
17 617 15.32936116
18 617 15.32936116
19 614 15.18065361
20 610 14.98350435
21 607 14.83648803
22 599 14.44798803 2000
Really nice inside 16 shots 2.7% ES, but seems like I run out of the sweet spot around 2200 or so.. with this set up, not sure if I can get that magic 24 shots. I'm starting to think the 1.25 TP is causing me to use more air then needed at this FPE. Hopefully the 1.05 TP from hillairgun will make it run more efficient! But I feel pretty good getting this ES, never happened before in any setting so that's a step in the right direction :D
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Thanks. It's a good thing I do enjoy the scientific process :) I bought some vibra-tite to toughen up the adjustments, hopefully that'll keep it in tune once I get the settings sorted out. My goal is to have it set up 20 PFE for 16 shots, 16 FPE 24 shots, and some absurd shot count for like 10-12FPE plinking, just by adjusting the HT and all under 4% ES. That would be success for me.
I have achieved your two higher powered strings with BSB on Prods. I never tried the lower powered tune, but many others have.
I found that vibra-tite did not work on the throw adjustment. As soon as you adjust it again, all the vibra-tite just peels off. Works better on the HS adjuster where the threads are more "loose". If yours is having problems holding, you can tap the front hole on the hammer for a set-screw, and insert weed eater line (small piece) and lock it down. You do have to be very careful you can break the tap off.
PS: the O-rings went out in the AM mail.
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I know this tune/post is about the PRod but I have my results on my 1720T.
I just wanted to be at or near 12fpe for possible FT use.
This one is close.
If I go to a 10.34 grain pellet I exceed 12fpe and the speed drops to around 800fps..
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Thanks. It's a good thing I do enjoy the scientific process :) I bought some vibra-tite to toughen up the adjustments, hopefully that'll keep it in tune once I get the settings sorted out. My goal is to have it set up 20 PFE for 16 shots, 16 FPE 24 shots, and some absurd shot count for like 10-12FPE plinking, just by adjusting the HT and all under 4% ES. That would be success for me.
I have achieved your two higher powered strings with BSB on Prods. I never tried the lower powered tune, but many others have.
I found that vibra-tite did not work on the throw adjustment. As soon as you adjust it again, all the vibra-tite just peels off. Works better on the HS adjuster where the threads are more "loose". If yours is having problems holding, you can tap the front hole on the hammer for a set-screw, and insert weed eater line (small piece) and lock it down. You do have to be very careful you can break the tap off.
PS: the O-rings went out in the AM mail.
Thank you!!
That’s good to know. Throw is already pretty tight it seems so hopefully that will hold. The spring is indeed the one that needs some help holding place
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Alright, found a setting that made me plenty happy! I ended up using 2 "X-rings" o rings that John (Fuzzygrub) sent me with a washer in the middle of them (got that idea from another post), .045 spring, 0 turn HT and 0.5 turn Spring. The washer seemed to take away a lot of the hammer bounce/farting at lower PSI I used to get below 2,000 with just o rings.
Here's what I got:
# FPS FPE PSI
1 623 15.63 3100
2 633 16.13
3 641 16.55
4 648 16.91
5 640 16.49
6 643 16.65 2800
7 648 16.91
8 656 17.33
9 653 17.17
10 664 17.75
11 661 17.59 2600
12 664 17.75
13 664 17.75
14 664 17.75
15 672 18.18 2400
16 669 18.02
17 672 18.18
18 664 17.75
19 669 18.02 2200
20 664 17.75
21 661 17.59
22 661 17.59
23 659 17.49 1900
24 653 17.17
25 659 17.49
26 646 16.80
27 643 16.65
28 641 16.55 1600
29 638 16.39
30 626 15.78 1500
From shots 3 through 28 (3000 psi to 1600 psi), gave me 26 shots at 17.4 FPE with 4.8% ES, can't complain ;D Going to put some vibra-tite on the spring screw to lock that in and call it a day o this gun. My first PCP and already itching for the next one..
Thanks all for the help and great discussions (especially to John for the generosity!!). Truly a great forum!
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Glad to see you got it tuned to where you want it to be. :)
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Nice bell curve Ben and glad you're happy with it. John is our resident Prod guru and has always been willing to help a fellow member.
I believe a Marauder would be a good one to put on your list for your next gun. They are truly awesome and versatile guns and tune very similar to the Prod.
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The Synthrod is definitely on my list, but in my current house, my yard is small (10 yards max distance from side to side..), don't think I can really have fun with a Synthrod's at that range. That's why I originally went with Prod (shooting from inside my house to end wall of yard is about 15 yards, which prod does great in). Shooting "at" rats in my backyard is fun too with the nimbleness of the prod (haven't got one yet). Was using a bugbuster scope, but couldn't lock on target fast enough in close quarters that is my small backyard. Just got some reflex sights which seems like it will work better (plus with 17 FPE for a rat.. probably don't need to be too accurate) :D.
In Southern California, unfortunately there's not a lot of open outdoor places I know of that I can just go set up targets and shoot..
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Yeah, a Synrod would be too much and too big for 10 yards ratting IMHO. Oh well I tried, lol.
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Your Synrod numbers look amazing though :o Maybe one day when I get a bigger yard I'll venture down that path.