GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: mackeral5 on September 30, 2018, 03:13:52 PM
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I ran a few strings with the P15 this afternoon. First I ran one with the valve return spring--75 shots of JSB 18.13 averaging 858fps for 29.6fpe. Then I degassed and removed the valve return spring. Reassembled without making any other adjustments.
The gun was much louder, I could tell it was wasting a lot of air. 48 shots averaging 883. 31.5fpe. I think excessive preload was bouncing the hammer off the valve.
I pulled my SSG and after testing various preloads I ended up setting it at the minimum preload possible. This still resulted in having a gap setting of approximately .120, far larger than I would typically run with an SSG. Even at this setting I couldn't dial velocity down as low as my first string.
This string was more quiet and resulted in 74 shots averaging 869fps/30.4fpe.
(http://i64.tinypic.com/2gt87wy.png)
These results do look promising. However I can't say for certain what is actually causing this.
Is it the fact that the valve is harder to open with the fairly strong valve return spring??
Is it due to the valve spring restricting airflow when compressed? I tend to think this is the case. I will post some pictures later illustrating why. The spring is relatively large wire diameter, with a lot of coils, and under significant preload when installed. There's not much room between coils for air to pass.
I don't want to deal with issues associated with no valve return spring, so i intend on buying/making a very light spring that is more of a poppet retainer than anything else.
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Yes, I need pictures! I don't know the the valves in the p15, so pictures will help me get it a lot better than a parts diagram for sure.
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If the P15 is a regulated gun .... some testing of set point pressure could very likely reduce the ES values your seeing.
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If the P15 is a regulated gun .... some testing of set point pressure could very likely reduce the ES values your seeing.
Understood on the ES, I need to turn the reg down just a little. Max velocity at this reg setting is a little over 900. The best ES I've seen with the OEM regulator is around 20 and that was at a higher preload/fpe setting.
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here are some pics.
valve body, oem poppet, a reduced stem peek poppet, and the oem poppet return spring
(http://i67.tinypic.com/xvdqw.jpg)
Looking into the plenum, with the oem spring inside
(http://i65.tinypic.com/2lmt4br.jpg)
The oem valve spring compresses to approximately .80" when installed.
(http://i66.tinypic.com/ajphja.jpg)
Here is a light spring I found to replace the oem spring with. I have to close the coils a bit to reduce OD, but it should work.
(http://i68.tinypic.com/14w9hqx.jpg)
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Likely able to reduce hammer weight too, and/or do some version of an SSG and get the valve dwell really under your control.
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Valve spring aside, I think making that PEEK poppet a bit larger in diameter(like the factory poppet), and squaring off the the sealing edge of the poppet is the way to go. That will make it close faster, while still making it relatively easy to crack the valve. But yeah, that valve spring is HUGE too!
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After seeing how much preload could be reduced after replacing the valve spring I am willing to up-size the poppet.
I was translating the OEM valve being hard to open due to excessive OD, but it appears that was due to an excessive valve spring.
Some time soon I'll make another poppet. For now she has a 70+ shot 30fpe tune..
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Thanks for these threads Mike, I am following with great interest and am taking notes along the way...Please let us know the results and size of the new Valve Spring
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Holy smokes , that valve spring looks like the hammer spring in my disco . Lol . Your tune doesn’t sound to be too bad as is . I’d really be looking at an SSG or even a short stiff spring to gain efficiency . Or once again a cobra spring system . I’m sure if you have the ability to make a peek poppet and have it seal you could make the cobra system . Can you take a few more pics of the valve ( complete if possible ) I’d like to see what the air inlet looks like .
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It is equipped with an SSG. There isn't much room in the p15 and you are pretty much limited to 5/16 OD or smaller springs. The oem spring has .048 wire, basically the same spring that is in a QB78. I haven't had much luck finding a heavier spring with .330 or less OD and at least .215 id to fit the spring guide.
Note the OEM hammer is just under 20grams. My hammer is just over 16 grams as I removed 2mm off the face to increase hammer throw. A little more was removed by drilling the spring hole deeper to allow room for my SSG's spring guide.
Next time I have the gun apart I will take some pics of the valve area-- there's not much to see. The silver valve carrier is recessed into the monoblock style breech assembly, then the plenum screws in to the monoblock. the threaded section of the plenum butts up against the valve carrier and the spring fits onto the poppet. You can see where the black anodize is wearing off from the plenum butting up against the valve carrier.
I've put the gun back stock and that results in 55-60 shots around 28fpe. I've read where Swish is getting 80 shots upwards of 30fpe out of a stock P15 with nothing but a preload adjustment. those are outstanding results, I have a hard time getting my head around them.....
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It is equipped with an SSG. There isn't much room in the p15 and you are pretty much limited to 5/16 OD or smaller springs. The oem spring has .048 wire, basically the same spring that is in a QB78. I haven't had much luck finding a heavier spring with .330 or less OD and at least .215 id to fit the spring guide.
Note the OEM hammer is just under 20grams. My hammer is just over 16 grams as I removed 2mm off the face to increase hammer throw. A little more was removed by drilling the spring hole deeper to allow room for my SSG's spring guide.
Next time I have the gun apart I will take some pics of the valve area-- there's not much to see. The silver valve carrier is recessed into the monoblock style breech assembly, then the plenum screws in to the monoblock. the threaded section of the plenum butts up against the valve carrier and the spring fits onto the poppet. You can see where the black anodize is wearing off from the plenum butting up against the valve carrier.
I've put the gun back stock and that results in 55-60 shots around 28fpe. I've read where Swish is getting 80 shots upwards of 30fpe out of a stock P15 with nothing but a preload adjustment. those are outstanding results, I have a hard time getting my head around them.....
Sorry I posted what I was getting but not how I got there.
I polished pretty much every moving part, including the springs. I also flat ground and polished the end of the springs and added a thin nylon washer or two to keep friction to a minimum.
I also ground the corner of the valve transfer port kinda like they do on 2240 valves for better flow. And if I remember correctly I opened up the barrel port a little as well.
The only other thing that is probably helping efficiency is i added a bstaley style oring. I apologize for not keeping better records but I did have to add a little hammer tension after the oring install so I'm pretty sure it's helping. After that I did the 80 shot string.
Counting a little reg creep at first and even few dry fires still a solid 75-80 shots. I love my Ping15! Lol.
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Hi Chad,
Where did you add the Bstaley Oring?
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It is equipped with an SSG. There isn't much room in the p15 and you are pretty much limited to 5/16 OD or smaller springs. The oem spring has .048 wire, basically the same spring that is in a QB78. I haven't had much luck finding a heavier spring with .330 or less OD and at least .215 id to fit the spring guide.
Note the OEM hammer is just under 20grams. My hammer is just over 16 grams as I removed 2mm off the face to increase hammer throw. A little more was removed by drilling the spring hole deeper to allow room for my SSG's spring guide.
Next time I have the gun apart I will take some pics of the valve area-- there's not much to see. The silver valve carrier is recessed into the monoblock style breech assembly, then the plenum screws in to the monoblock. the threaded section of the plenum butts up against the valve carrier and the spring fits onto the poppet. You can see where the black anodize is wearing off from the plenum butting up against the valve carrier.
I've put the gun back stock and that results in 55-60 shots around 28fpe. I've read where Swish is getting 80 shots upwards of 30fpe out of a stock P15 with nothing but a preload adjustment. those are outstanding results, I have a hard time getting my head around them.....
Sorry I posted what I was getting but not how I got there.
I polished pretty much every moving part, including the springs. I also flat ground and polished the end of the springs and added a thin nylon washer or two to keep friction to a minimum.
I also ground the corner of the valve transfer port kinda like they do on 2240 valves for better flow. And if I remember correctly I opened up the barrel port a little as well.
The only other thing that is probably helping efficiency is i added a bstaley style oring. I apologize for not keeping better records but I did have to add a little hammer tension after the oring install so I'm pretty sure it's helping. After that I did the 80 shot string.
Counting a little reg creep at first and even few dry fires still a solid 75-80 shots. I love my Ping15! Lol.
Chad thanks for sharing. We are very similar regarding mods. There is something I am missing. I need to check basics such as probe depth, barrel port alignment, etc. something just seems to be off.....
Also, I finally got my head around the whole Cobra concept, thanks to Hobbyman's example with his Rainstorm. I'm pretty sure I can pull it off, but I'm not sure if it will be the P15, R3M, or one of my QB's. I really want to try it on the Edgun, but the p15 has my attention right now. The p15 will be the most challenging as it has the smallest space to work. The Edgun will be the easiest due to its cavernous valve body.....
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Hi Chad,
Where did you add the Bstaley Oring?
The Bstaley mod is when you add 1 or more orings between the hammer and the valve. Usually they stack against the face of the valve to cushion and rebound the valve closed faster. Or not open the valve farther/longer than need be.
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It is equipped with an SSG. There isn't much room in the p15 and you are pretty much limited to 5/16 OD or smaller springs. The oem spring has .048 wire, basically the same spring that is in a QB78. I haven't had much luck finding a heavier spring with .330 or less OD and at least .215 id to fit the spring guide.
Note the OEM hammer is just under 20grams. My hammer is just over 16 grams as I removed 2mm off the face to increase hammer throw. A little more was removed by drilling the spring hole deeper to allow room for my SSG's spring guide.
Next time I have the gun apart I will take some pics of the valve area-- there's not much to see. The silver valve carrier is recessed into the monoblock style breech assembly, then the plenum screws in to the monoblock. the threaded section of the plenum butts up against the valve carrier and the spring fits onto the poppet. You can see where the black anodize is wearing off from the plenum butting up against the valve carrier.
I've put the gun back stock and that results in 55-60 shots around 28fpe. I've read where Swish is getting 80 shots upwards of 30fpe out of a stock P15 with nothing but a preload adjustment. those are outstanding results, I have a hard time getting my head around them.....
Sorry I posted what I was getting but not how I got there.
I polished pretty much every moving part, including the springs. I also flat ground and polished the end of the springs and added a thin nylon washer or two to keep friction to a minimum.
I also ground the corner of the valve transfer port kinda like they do on 2240 valves for better flow. And if I remember correctly I opened up the barrel port a little as well.
The only other thing that is probably helping efficiency is i added a bstaley style oring. I apologize for not keeping better records but I did have to add a little hammer tension after the oring install so I'm pretty sure it's helping. After that I did the 80 shot string.
Counting a little reg creep at first and even few dry fires still a solid 75-80 shots. I love my Ping15! Lol.
Chad thanks for sharing. We are very similar regarding mods. There is something I am missing. I need to check basics such as probe depth, barrel port alignment, etc. something just seems to be off.....
Also, I finally got my head around the whole Cobra concept, thanks to Hobbyman's example with his Rainstorm. I'm pretty sure I can pull it off, but I'm not sure if it will be the P15, R3M, or one of my QB's. I really want to try it on the Edgun, but the p15 has my attention right now. The p15 will be the most challenging as it has the smallest space to work. The Edgun will be the easiest due to its cavernous valve body.....
My reg is set right close to 120 bar if that helps any. It was closer to 140 out of the box.
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Thanks again. My reg is currently in the 120-125bar range, its hard to be precise. This regulator has not been rebuilt with fresh orings and polished bellvilles like the one I have attached to the plenum extension....
I checked pellet seating depth by seating a pellet then removing the barrel, wouldn't you know--when seated, you can see the pellet skirt in the edge of the barrel port. When pushing the pellet beyond the barrel port you feel a distinct hump/resistance, then it breaks free.
At this time I haven't determined what exactly to do to resolve--i have a spare probe, etc so there are options. I ran out of time tonight.
I reassembled and ran several 15 shot strings to see how this affected performance. Some in the middle of the pressure range and some at the top of a full fill. There were 2 versions of strings. The first version was seating pellets only with the bolt, waiting 30 seconds, then firing.
These averaged 870FPS with ES of 20
The next strings I seated pellets with the bolt, then used an allen wrench to seat the pellets another .080" or so. I could feel the initial resistance of the skirt being in the barrel port then break free as the pellet moved beyond the barrel port.
These averaged 879 with an ES of 15.
Its not the largest sample, but there were at least 45 shots of each version fired and both versions had 1 group of 15 from a 3500psi fill.
In comparing 2 bolt probes I wasn't lucky enough to find one longer than the other....so it's not going to be as simple as swapping bolts. I do plan to fully disassemble and verify barrel port to transfer port alignment before making any changes.
More to follow.
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Hi Chad,
Where did you add the Bstaley Oring?
The Bstaley mod is when you add 1 or more orings between the hammer and the valve. Usually they stack against the face of the valve to cushion and rebound the valve closed faster. Or not open the valve farther/longer than need be.
Thanks Chad
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This evening I pulled the valve body then reassembled the tube, monoblock, and barrel assemblies together. Essentially mocked it up without any internals. though I cannot see that far into the transfer port, i was able to use a small allen wrench to feel for a smooth transition from transfer port to barrel port. I cannot feel the transition between the two ports except towards the butt. There is a distinct mismatch in the rear of the ports--call it the rear 1/4.
The breech end of the barrel is flush with the monoblock and the step down machined into the barrel is flush against the front of the monoblock. So the barrel is fully seated. It appears barrel port and monoblock transfer port are slightly out of tolerance, with the barrel port located a little forward of the transfer port in the monoblock. The amount appears to match the amount of pellet skirt exposed in the barrel port when testing pellet seating depth.
Now I just have to figure out the best way of resolving. I see a few options: 1) plug the port, spin the barrel and drill a new transfer port. 2) machine the barrel to move it rearward and then take a little off the breech end of the barrel to keep it flush with the monoblock. 3) enlarge the rear of the barrel port to match the transfer port and make a longer probe.....
I think option 1 may be the best solution???
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I vote option 2. Also, doing option 2, would also effectively move the probe farther into the barrel. Something about plugging the barrel and getting that right seems more complicated, and prone to a possible failure? Option 3, seems like more work and opening the barrel port more could cause loading failures?
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I kinda like option 1 and wonder if you would even need to plug the original hole if it was turned up to 12 o'clock. It seams like as long as the pellet slid past it ok you'd be fine.
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I appreciate the input. Options 1 and 2 have their merits and challenges. Option 3 I believe is the least attractive if only due to the potential of an unnecessarily oversized barrel port.
The way the p15 js assembled creates some challenges for option 2--- by moving the barrel back it would also require a dimple in the barrel to be oblonged so that the scope rail assembly (and forward stock mounting hole) doesn't move rearward as well. This dimple locates a set screw in the rear barrel band.
Option 1 will require 3 steps. 1) Plug the old port. 2) drill/finish the new barrel port 3) create new dimple on barrel for the set screw.
Option 2 I am not equipped to do, at least I am not equipped to do it in a manner that is guaranteed to not look poorly. I can make it work, but it is going to be ugly
Option 1 I can do and have done before.
Before making a final decision. I need to mock up the bolt/sidelever in the monoblock. I need to ensure the bolt and transfer port are properly oriented----- if the transfer port is forward of the bolt this will bring another variable into the mix...... In hindsight I should have checked this first and i wouldn't have had to reassemble the bolt and sidelever.
This is one example of how SPA can cram so much value into a $600 gun...most owners would likely never known any different. Once resolved it will be one more bit of satisfaction I'll get from my P15 experience---we all buy these guns for different reasons. I tend to enjoy this aspect of it. Let's hope I don't make any mistakes and can simply execute on a plan.
BTW, I just realized how many pellets and how much nitrogen I've wasted collecting BAD data. I can only roll my eyes and laugh at myself for not finding this sooner. I was in to big of a hurry trying to make the p15 "better" and failed to make sure it was "right" to begin with. Hopefully at age 45 I've learned this lesson for the last time. Something tells me I haven't, lol.
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Don't forget, you can just put a new dimple in the front barrel band instead of the rear one. I put a set screw in the forward one just cause. Even without a dimple.
Besides if you spun the barrel 180 you'd have a new spot for a new dimple anyhow.
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I would move the whole barrel to the rear. Here is why. My P15 had accuracy issues that were solved when I seated the pellet deeper than the probe would. I have been following your P15 threads and I never read anything about how accurate your gun is. You have been chasing power and efficiency and it would be a shame if you found what you are looking for only to have a gun that shoots like a shotgun at 50yrds. Your gun can only benefit from having that pellet seated a little deeper into the rifling.
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I would move the whole barrel to the rear. Here is why. My P15 had accuracy issues that were solved when I seated the pellet deeper than the probe would. I have been following your P15 threads and I never read anything about how accurate your gun is. You have been chasing power and efficiency and it would be a shame if you found what you are looking for only to have a gun that shoots like a shotgun at 50yrds. Your gun can only benefit from having that pellet seated a little deeper into the rifling.
I agree. I was leaning towards option 1 because of being easier to do. After reading the post I checked mine immediately. The back of a cphp is flush with the edge of the transfer port. It doesn't feel like it seats the pellet head very well.
Mine shoots about 1" groups off the bench at 55 yards with 16grn JSB's. Most of them land in about 1/2" so I will definitely run some accuracy testing soon with seating the pellets better. I may have to end up needing to adjusting my barrel as well.
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I would move the whole barrel to the rear. Here is why. My P15 had accuracy issues that were solved when I seated the pellet deeper than the probe would. I have been following your P15 threads and I never read anything about how accurate your gun is. You have been chasing power and efficiency and it would be a shame if you found what you are looking for only to have a gun that shoots like a shotgun at 50yrds. Your gun can only benefit from having that pellet seated a little deeper into the rifling.
I agree. I was leaning towards option 1 because of being easier to do. After reading the post I checked mine immediately. The back of a cphp is flush with the edge of the transfer port. It doesn't feel like it seats the pellet head very well.
Mine shoots about 1" groups off the bench at 55 yards with 16grn JSB's. Most of them land in about 1/2" so I will definitely run some accuracy testing soon with seating the pellets better. I may have to end up needing to adjusting my barrel as well.
Sounds like good advice to me. I chose option 2. Point well taken regarding accuracy. All of my posts for the past year or so have been around tuning for efficiency at a given FPE. Currently life doesn't allow for much else, so accuracy is taking a back seat at this time. At some point I'll get to spend more time focusing on targets and less on the chronograph.
I had to determine the best way for me to perform option 2 with my current abilities/tooling.
i made a slight change to the breech/monoblock- a slight countersink added to the breech to allow the shoulder on the barrel to recess a bit into the breech, resulting in the barrel sitting a bit farther back. Now a drill bit inserted from the transfer port hole fits perfectly in the barrel port when the barrel is fully seated. pellets seat just past the parrel port now. It is virtually unnoticeable when assembled. I machined the rear of the barrel flush with the breech by spinning it in a drill while running it against my 1" wide vertical belt sander--it's a WorkSharp knife sharpener sees a lot of uses other than sharpening knives. Using this method I ended up with a perfectly smooth and square finish.
I hope to reassemble and have some test results to post later this evening.
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Great idea on the countersink! I think we may be working out of the same machine shop. Lol.
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I would move the whole barrel to the rear. Here is why. My P15 had accuracy issues that were solved when I seated the pellet deeper than the probe would. I have been following your P15 threads and I never read anything about how accurate your gun is. You have been chasing power and efficiency and it would be a shame if you found what you are looking for only to have a gun that shoots like a shotgun at 50yrds. Your gun can only benefit from having that pellet seated a little deeper into the rifling.
I agree. I was leaning towards option 1 because of being easier to do. After reading the post I checked mine immediately. The back of a cphp is flush with the edge of the transfer port. It doesn't feel like it seats the pellet head very well.
Mine shoots about 1" groups off the bench at 55 yards with 16grn JSB's. Most of them land in about 1/2" so I will definitely run some accuracy testing soon with seating the pellets better. I may have to end up needing to adjusting my barrel as well.
Sounds like good advice to me. I chose option 2. Point well taken regarding accuracy. All of my posts for the past year or so have been around tuning for efficiency at a given FPE. Currently life doesn't allow for much else, so accuracy is taking a back seat at this time. At some point I'll get to spend more time focusing on targets and less on the chronograph.
I had to determine the best way for me to perform option 2 with my current abilities/tooling.
i made a slight change to the breech/monoblock- a slight countersink added to the breech to allow the shoulder on the barrel to recess a bit into the breech, resulting in the barrel sitting a bit farther back. Now a drill bit inserted from the transfer port hole fits perfectly in the barrel port when the barrel is fully seated. pellets seat just past the parrel port now. It is virtually unnoticeable when assembled. I machined the rear of the barrel flush with the breech by spinning it in a drill while running it against my 1" wide vertical belt sander--it's a WorkSharp knife sharpener sees a lot of uses other than sharpening knives. Using this method I ended up with a perfectly smooth and square finish.
I hope to reassemble and have some test results to post later this evening.
Awesome, I look forward to seeing how it works out!
Great idea on the countersink! I think we may be working out of the same machine shop. Lol.
A lot of us are working out of that machine shop :D
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It is amazing how easy the p15's monoblock design js to disassemble and reassemble. No need for a ramrod unless the reg wasn't secured right enough to the plenum, which is an easy thing to prevent. I didn't have much time, but initial results look to be a slight improvement. Clambering a pellet feels different now.
I have a love/hate relationship with that machine shop. I dont think I would refer any business there, but I keep going back, lol