GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Kerndtc on October 05, 2018, 01:14:36 PM
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I'm currently converting mine into a medium/ long range ground squirrel gun.
I've tuned 5 guns for customers all in .177 for plinking or a spare FT gun and know their guts pretty well.
My first gauntlet had been sitting in the safe because of a bad barrel and Umarex won't sell me a replacement. After many emails and a few phone calls they decided to send me a RMA and a slip to ship it to them. Long story short, they tested the gun and sent it back. The gun box had two targets inside, one 10 yard target with a 1/2" group and a 25 yard 1.5" group. They said it was a 1" group because there were only 2 pellets out of five that brought it out to 1.5". How ridiculous.i proceeded to tell them that I have had three other gauntlets in my hands that shot better groups at 55 yards than this one did at 25. Their simple reply was that my gun was accurate enough for their standards.
Customer service? Eh not so good.
Anywho, since it was been sitting I've been stewing on how I am going to make this into a squirrel shooter by installing a good barrel and tuning it up in power a little bit.
Wednesday afternoon my new .22 Cal Lothar Walther Polygon barrel arrived. That night at around 9pm I decided this needed to happen haha.
Spent about 2 hours getting the barrel turned down to fit the Gauntlets breech, cutting the O-ring grooves, drilling the transfer port, polishing the lead and sizing it for the bolt brobe oring, facing the muzzle and crowning the barrel after recessing it slightly to protect itself. I also matched the barrel port and the breech port to the .181 porting of the valve. Then lapped the barrel. Also ground down the breech/ stock mounting cylinder to increase the stroke of the valve and dwell time.
After that I shot it over the chrony and was shooting 14.3 Jsbs around 820fps. Not bad for a good shotcount, but I wanted more.
Knowing the gun was originally designed for C02 and the valve only uses one screw to keep it in place as well as align the TP while snugging up the valve body to compress the oring. I decided to install two screws, they are high strength black low profile socket head 6-32 screws. I grabbed some tape and wrapped the tube around the center of where the existing valve screw was then marked two spots in the tube just 1/16" towards the hammer side of the valve to gain more clearance between the screw head and the valve oring.
Happy with my results I proceeded to increase my reg pressure by stacking the Belleville washers and adding a .050 shim. This brought me to 1500psi on my reg tester.
I also decided to make a PEEK poppet for my valve to decrease the diameter of the overall poppet while not losing strength and creating a more efficient valve seat.
Shot it over the chrony this morning, I am happy :)
Shot a full magazine, extreme spread was less than 10, and a decent amount of hammer bounce. (Will address that next)
955fps average with 15.9gr jsb. Ran out of 18.1gr and don't have any monsters.
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Cameron
Thank you for that info,
The Gauntlet is my next one,
planning on doing the same mods along the way.
Question for you,
What is the dimensions of the hammer spring and inside the hammer hole?
I am planning on using a flat spring to replace the OEM hammer spring,
along with a SSG installed etc.
Tia,
Don
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Cameron
Thank you for that info,
The Gauntlet is my next one,
planning on doing the same mods along the way.
Question for you,
What is the dimensions of the hammer spring and inside the hammer hole?
I am planning on using a flat spring to replace the OEM hammer spring,
along with a SSG installed etc.
Tia,
Don
I'm unsure of the exact measurements of the hammer spring and the ID of the hammer, but I think the spring is nearly 5/16 od and the hammer itself would be slightly more. Will measure when I get home from work.
Are you saying to want to run a conical/ cone shaped spring? I haven't experimented with that but it is very doable
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@Cameron - I tried to PM you, but your inbox was full. Just wanted to let you know I moved this thread to the PCP Gate.
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@Cameron - I tried to PM you, but your inbox was full. Just wanted to let you know I moved this thread to the PCP Gate.
Erasing messages now,
Thanks!
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You have some mad skills Cameron! Cant wait to see what you have done!
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i have gotten my gauntlet .22 in the 40 fpe range for 80 shots with 26ci bottle running 1200psi shooting 28 grains at 815fps. this is done with the original gauntlet co2 tube. you can get a 2000psi tube and max it out for more power. at your current setting its not the max. you can do more
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i have gotten my gauntlet .22 in the 40 fpe range for 80 shots with 26ci bottle running 1200psi shooting 28 grains at 815fps. this is done with the original gauntlet co2 tube. you can get a 2000psi tube and max it out for more power. at your current setting its not the max. you can do more
You got it to 40fpe with the reg at 1200psi?
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Here’s one I did open reg. Full pressure Jsb monsters 2 extra valve retainers. Running JSAR tune kit and full bore porting.
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Cameron
Here is the type of main Hammer spring I am running at this time,
https://www.ebay.com/itm/1911-45-FLAT-WIRE-RECOIL-SPRING-18LB-GENUINE-SIG-SAUER/263682329790?hash=item3d64b10cbe:g:m40AAOSwNSZa91-V:sc:USPSFirstClass (https://www.ebay.com/itm/1911-45-FLAT-WIRE-RECOIL-SPRING-18LB-GENUINE-SIG-SAUER/263682329790?hash=item3d64b10cbe:g:m40AAOSwNSZa91-V:sc:USPSFirstClass)!89419!US!-1
Also have this flat wire spring, but have not used it yet,
https://www.ebay.com/itm/Wilson-Combat-1911-Flat-Wire-17LB-Recoil-Spring-5-Full-Size-45-ACP/321954337373?epid=10011373504&hash=item4af5f9525d:g:C~oAAOSwUdlWdtWZ:sc:USPSFirstClass (https://www.ebay.com/itm/Wilson-Combat-1911-Flat-Wire-17LB-Recoil-Spring-5-Full-Size-45-ACP/321954337373?epid=10011373504&hash=item4af5f9525d:g:C~oAAOSwUdlWdtWZ:sc:USPSFirstClass)!89419!US!-1
This spring provides very uniform results, very easy to cock (as compared to a round coil spring of same power),
the outside dia is .415" and inside dia is .265", these 5-3/4" long springs will go coil bound at 1.030", fully compressed,
and you can't do that with a round coil spring.........
I used the full length and then kept reducing the length, by 2-4 coils,
until I found a good usable option with the SSG, without going spring coil bound etc, and have all the power I need so far.
I am running a 4-1/4" long, 18# spring in my QB and I can cock it with 1 finger,
If you have the space/dimensions to run this type of spring in your Gauntlet,
you might want to try one, sure made my mods/adjustments easier, now that I found/tried them etc.
These springs come in several lengths, for the Colt/1911 series of pistol springs,
1911 is the longest, at 5-3/4 to 6" length, Commander is the next shorter, and Officer is the shortest.
Plus there is other pistol brand names that use these same spring, I don't remember all the lengths etc.
If you get/use one, I would greatly appreciate any and all info......... you find out. ;)
Tia,
Don
Cameron
Thank you for that info,
The Gauntlet is my next one,
planning on doing the same mods along the way.
Question for you,
What is the dimensions of the hammer spring and inside the hammer hole?
I am planning on using a flat spring to replace the OEM hammer spring,
along with a SSG installed etc.
Tia,
Don
I'm unsure of the exact measurements of the hammer spring and the ID of the hammer, but I think the spring is nearly 5/16 od and the hammer itself would be slightly more. Will measure when I get home from work.
Are you saying to want to run a conical/ cone shaped spring? I haven't experimented with that but it is very doable
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Thought about putting one of these Wilson flat coil springs in my Les Baer. They have the ability to be cycled many more times than a standard round wire coil spring of the same weight. ;)
A shame I can't find any large enough dia. for the Rainstorm. GRRRR!
Knife
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Here’s one I did open reg. Full pressure Jsb monsters 2 extra valve retainers. Running JSAR tune kit and full bore porting.
Holy cow! That's some power for sure.
Was that a factory tube? I really don't know what the safety factor is for the airtube, but I'd be curious if you have any of that information. I think 2,000 psi would be the highest I want to go.
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Cameron
Here is the type of main Hammer spring I am running at this time,
https://www.ebay.com/itm/1911-45-FLAT-WIRE-RECOIL-SPRING-18LB-GENUINE-SIG-SAUER/263682329790?hash=item3d64b10cbe:g:m40AAOSwNSZa91-V:sc:USPSFirstClass (https://www.ebay.com/itm/1911-45-FLAT-WIRE-RECOIL-SPRING-18LB-GENUINE-SIG-SAUER/263682329790?hash=item3d64b10cbe:g:m40AAOSwNSZa91-V:sc:USPSFirstClass)!89419!US!-1
Also have this flat wire spring, but have not used it yet,
https://www.ebay.com/itm/Wilson-Combat-1911-Flat-Wire-17LB-Recoil-Spring-5-Full-Size-45-ACP/321954337373?epid=10011373504&hash=item4af5f9525d:g:C~oAAOSwUdlWdtWZ:sc:USPSFirstClass (https://www.ebay.com/itm/Wilson-Combat-1911-Flat-Wire-17LB-Recoil-Spring-5-Full-Size-45-ACP/321954337373?epid=10011373504&hash=item4af5f9525d:g:C~oAAOSwUdlWdtWZ:sc:USPSFirstClass)!89419!US!-1
This spring provides very uniform results, very easy to cock (as compared to a round coil spring of same power),
the outside dia is .415" and inside dia is .265", these 5-3/4" long springs will go coil bound at 1.030", fully compressed,
and you can't do that with a round coil spring.........
I used the full length and then kept reducing the length, by 2-4 coils,
until I found a good usable option with the SSG, without going spring coil bound etc, and have all the power I need so far.
I am running a 4-1/4" long, 18# spring in my QB and I can cock it with 1 finger,
If you have the space/dimensions to run this type of spring in your Gauntlet,
you might want to try one, sure made my mods/adjustments easier, now that I found/tried them etc.
These springs come in several lengths, for the Colt/1911 series of pistol springs,
1911 is the longest, at 5-3/4 to 6" length, Commander is the next shorter, and Officer is the shortest.
Plus there is other pistol brand names that use these same spring, I don't remember all the lengths etc.
If you get/use one, I would greatly appreciate any and all info......... you find out. ;)
Tia,
Don
Cameron
Thank you for that info,
The Gauntlet is my next one,
planning on doing the same mods along the way.
Question for you,
What is the dimensions of the hammer spring and inside the hammer hole?
I am planning on using a flat spring to replace the OEM hammer spring,
along with a SSG installed etc.
Tia,
Don
I'm unsure of the exact measurements of the hammer spring and the ID of the hammer, but I think the spring is nearly 5/16 od and the hammer itself would be slightly more. Will measure when I get home from work.
Are you saying to want to run a conical/ cone shaped spring? I haven't experimented with that but it is very doable
Wow, what useful Info! I can make it whatever diameter to fit a spring like that. I've only seen a few of those and they were very intriguing.
I'll have to order a couple and try them out!
If I get them I'll let you know my results.
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Knife maker
What size and power rating do you need for that Rainstorm,
I found some that were too large (dia) for my use.
Tia,
Don
Thought about putting one of these Wilson flat coil springs in my Les Baer. They have the ability to be cycled many more times than a standard round wire coil spring of the same weight. ;)
A shame I can't find any large enough dia. for the Rainstorm. GRRRR! Knife
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Here’s one I did open reg. Full pressure Jsb monsters 2 extra valve retainers. Running JSAR tune kit and full bore porting.
Holy cow! That's some power for sure.
Was that a factory tube? I really don't know what the safety factor is for the airtube, but I'd be curious if you have any of that information. I think 2,000 psi would be the highest I want to go.
I must apologize, my set up measured 40fpe at 1200psi was with a Discovery tube, using the largest available air space possible. When i switched back to the Gauntlet stock tube with the reg at 1200psi, i saw a drop of 15fps. I could easily up the PSI or up the preload but i never saw the need since i only shoot crossman 14.3 grains now. Funny thing is, Co2 at 1000psi was running 830fps with 14grains. and 850fps with 500psi hpa. If i decide to run on Co2, i can have 500 shots per fill! or run on 500psi bottle for practice.
When Oldpro said open reg, it's certainly 3000psi and certainly not stock tube, my stock tube experienced some minor deformation at 1400psi with the stock valve screw. My transfer port to barrel is at .190, but my horizontal valve hole and seat is at .235 and all the corners are beveled/countersunk out to allow for more airflow, even the spring housing is ported out.
Oldpro sir, how many shots you get with your setup? 15?
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Here’s one I did open reg. Full pressure Jsb monsters 2 extra valve retainers. Running JSAR tune kit and full bore porting.
The pressure tube is more than adequate for 3k pressure it’s the valve retention screws that is the weak point and the cheap hardware. Fix those things and 3k is no problem
Holy cow! That's some power for sure.
Was that a factory tube? I really don't know what the safety factor is for the airtube, but I'd be curious if you have any of that information. I think 2,000 psi would be the highest I want to go.
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Here’s one I did open reg. Full pressure Jsb monsters 2 extra valve retainers. Running JSAR tune kit and full bore porting.
Holy cow! That's some power for sure.
Was that a factory tube? I really don't know what the safety factor is for the airtube, but I'd be curious if you have any of that information. I think 2,000 psi would be the highest I want to go.
I must apologize, my set up measured 40fpe at 1200psi was with a Discovery tube, using the largest available air space possible. When i switched back to the Gauntlet stock tube with the reg at 1200psi, i saw a drop of 15fps. I could easily up the PSI or up the preload but i never saw the need since i only shoot crossman 14.3 grains now. Funny thing is, Co2 at 1000psi was running 830fps with 14grains. and 850fps with 500psi hpa. If i decide to run on Co2, i can have 500 shots per fill! or run on 500psi bottle for practice.
When Oldpro said open reg, it's certainly 3000psi and certainly not stock tube, my stock tube experienced some minor deformation at 1400psi with the stock valve screw. My transfer port to barrel is at .190, but my horizontal valve hole and seat is at .235 and all the corners are beveled/countersunk out to allow for more airflow, even the spring housing is ported out.
Oldpro sir, how many shots you get with your setup? 15?
Your correct that’s why I clearly stated I had additional valve screws very similar to your set up. The pressure tube is rated much higher than the hardware or stock fasteners will allow
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When the conversation shifts to include disco tubes and higher pressures the easily obtained fpe becomes a considerably higher. For example, I have a disco tubed Qb78 repeater in .22, the Gauntlet predecessor, that does up to 60fpe regulated at 2200psi. Unregulated it pushes almost 70fpe. With a 350cc carbon bottle shot count easily exceeds 60 shots above 50fpe.
When I saw this thread it peaked my interest as I've often wondered about the slightly larger-than-qb79 plenum of the gauntlet.
Am I reading this right???--factory tubed, regulated Gauntlets seem to max out in the 30 fpe range with decent shot count, as high as 40fpe running wide open.
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While the pressure tube is undoubtedly far stronger than the stock valve screws.... I would imagine it is the same dimensions as a QB tube, namely 22m OD x 19mm ID.... and we don't know what the material is.... If it is 1018 steel or equivalent, then 2500 psi would result in a 3.5:1 safety margin to burst.... Drop that down to low carbon steel such as 1006, the MSWP drops to about 1800 psi.... Bump it up to 1026 DOM tubing and then 3000 psi becomes possible.... This assumes that all fastenings (valve attachment, tank block attachment, etc.etc.) are up to the job....
BTW, can somebody please tell me what the plenum volume on the Gauntlet is?.... or the length from front of valve to back of tank block stub?....
Bob
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While the pressure tube is undoubtedly far stronger than the stock valve screws.... I would imagine it is the same dimensions as a QB tube, namely 22m OD x 19mm ID.... and we don't know what the material is.... If it is 1018 steel or equivalent, then 2500 psi would result in a 3.5:1 safety margin to burst.... Drop that down to low carbon steel such as 1006, the MSWP drops to about 1800 psi.... Bump it up to 1026 DOM tubing and then 3000 psi becomes possible.... This assumes that all fastenings (valve attachment, tank block attachment, etc.etc.) are up to the job....
BTW, can somebody please tell me what the plenum volume on the Gauntlet is?.... or the length from front of valve to back of tank block stub?....
Bob
Bob i cut my stock Gauntlet tube and ended up being junk due to improper nickel plating, so i couldnt tell you the exact number. but i know its not much, i can confirm the number when i get home but i think its 5-6 inches overall available plenum. i cannot use 1026 dom tube due to rust development over time. custom tubes really need some sort of coating or they wont resist corrosion for long.
Mike D, stocktube, stock everything...but bored valve and shortened hammer block. i hit 1050fps with 14.3grains at 1200psi. i am sure i can go faster with heavier hammer/spring and higher psi. so 40fpe is not the limit for stock tube.
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Behold Bob, its only 4 inches give or take 1/4 inch length worth of metal shavings i cut off. so 4.25 inches from valve transfer port to back of regulator block. and if you want a true measurement. its 3.57 inches from back of reg block to the valve threads. isnt that 25cc with .748id?
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I am confused.... You machined off the sides of the valve, yes?.... A stock QB valve is about 5 cc inside, but the front of the valve would take up more than 1" of that 3.57" length.... It looks to me like the stock plenum is only 2 1/4 - 2 1/2" long, or about 16-18 cc, plus the valve volume.... If you can give me the distance from the front of the valve to the back of the tank block, then I will know for sure....
Bob
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Bob, that is actually a stock Gauntlet valve unlike the QB78 stock valve. The sides of the valve have been machined from the factory or as you see in the picture. I now call front of the valve simply "valve spring housing". so from the valve spring housing to the back of reg block, is 2.6 inches. with the valve sides machined like that, it gives way for better flow and available air is closer to the valve transfer port than at the front depinger port.
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Thanks for that.... Yes, I would say that including the valve volume the plenum is about 25cc.... That is close to the shortened QB78 tube I had, which was 30cc including the valve.... It had lots of power in .22 cal, and decent efficiency.... but I felt it would have been too small in .25 cal, so I used a full '78 tube (51 cc plenum) for that....
Bob
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Bob, is there a write up on a QB in .25? I am also eager to see what you did to your .22 QB to get lots of power, it's settings and efficiency.
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Duy, the .22 cal with the shortened QB78 tube was done before I joined the GTA.... but the first thread linked below has the details.... The .25 cal. had a reversed tank block, so the whole '78 tube was available as a plenum.... That is in thread #2....
(http://i378.photobucket.com/albums/oo221/rsterne/QB%20on%20HPA/FirstAssembly.jpg) (http://s378.photobucket.com/user/rsterne/media/QB%20on%20HPA/FirstAssembly.jpg.html)
My QB modding threads are mostly in the Workshop.... here are the ones I found in a quick search....
https://www.gatewaytoairguns.org/GTA/index.php?topic=21681. (https://www.gatewaytoairguns.org/GTA/index.php?topic=21681.)
https://www.gatewaytoairguns.org/GTA/index.php?topic=25524.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=25524.0)
https://www.gatewaytoairguns.org/GTA/index.php?topic=49943. (https://www.gatewaytoairguns.org/GTA/index.php?topic=49943.)
I addition, anyone modding a QB should read this thread on the safety of the tank block installation....
https://www.gatewaytoairguns.org/GTA/index.php?topic=105712.20 (https://www.gatewaytoairguns.org/GTA/index.php?topic=105712.20)
Bob
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excellent reads Bob, love the .25 tank block power and efficiency at 1600 psi. when I get the time to work on my Gauntlet again, I am going to max it out. I think i hit the plateau at 35-40 fpe at 1200 psi currently, I will put the work on here once it's done in a couple of weeks. It's so much fun modding the QB series, Troy Hammer even converted some QB78s to .357 shooting 81 grains above 100fpe for a few shots. I'll settle for 60 fpe for more shots on a .22
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So i had some time to put the Gauntlet together again. this time i tested the shortened tube. i got 756fps with 28.6 (14.3x2pellets) grains at 1300psi. compared to the full discover tube 815fps at 1200psi. i cut off 1.78 inches or 0.9 inches off the plenum. i only have about 17-19cc left from 25cc. i am sure with the stock tube i can get 40fpe at 1300psi easily. so my claim was only 100 psi off on the full discovery tube. sadly thats part of getting older.
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actually. i turned the hammer preload some more until i could not pull the bolt back anymore. and i got 770fps with 28.6 grains. so i wans’t going senile. thats already 38fpe with a shortened tube.