QB79 Ninja - The $200 PCP



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Offline rsterne

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QB79 Ninja - The $200 PCP
« on: July 15, 2013, 06:13:09 PM »
This thread will be slightly different than most of mine, in that it is about building a very simple yet efficient PCP for about $200.... You won't need any special tools, and there are only two things to purchase:

An Industry Brand QB79 Airgun
A Ninja 13CI/3000 psi tank with an SHP Pro Regulator

What you end up with is a gun that looks like this.... It weighs 6 lb. 10 oz. and balances right on the foregrip....



and shoots like this.... In fact twice that many shots on a full tank....



The average velocity while above the regulator setpoint was 609 fps with Crosman 14.3 gr. CPHP pellets, which works out to 11.8 FPE.... On a 3000 psi fill, it works out to 135 shots and refilling at 1100 psi.... for an efficiency of 0.95 FPE/CI....

What does it take to accomplish this great combination?.... Would you believe mount the tank on the gun, fill it with air and start shooting?.... First a little history.... The QB79 is the "tanker" version of the QB78, which was developed from the Crosman 160, and manufactured in China.... It is available for between $100-$120, and is intended to use a CO2 Paintball tank, although many people substitute Paintball HPA setups instead.... So what did I do that was different?.... Instead of the commonly available 13 CI / 3000 psi tanks that have a regulated output of 800-850 psi, I used Ninja Paintballs new SHP Pro version.... The "SHP" stands for "super high pressure" (advertised at 1100 psi) and the "Pro" refers to their "360* twist technology" which allows the tank to be rotated so that the fill nipple and gauge don't interfere with the barrel.... I recently reviewed the SHP Pro, which lists for $80 US, here.... http://www.gatewaytoairguns.org/GTA/index.php?topic=49648.0

OK, so the QB79 is designed for CO2, but we're running 1100 psi, what about safety?.... What people forget is that CO2, while having a nominal pressure of 850 psi at 70*F, can produce pressures as high as 1900 psi at 120*F.... At 90*F, it's about 1200 psi, and at 100*F about 1400.... and we don't hear of QB79's exploding on a hot day.... About all that happens is that when it gets hot, the velocity drops, because the hammer spring peaks out at about 1100-1200 psi.... Having said that, there are a couple of recommendations I have on the QB79, whether on HPA or on CO2....

Don't remove the action from the stock with gas in the gun.... There are two additional stock screws that thread into the tank block and provide an additional safety measure should the other screws yield....

Don't remove the breech with gas in the gun.... The valve is only secured with one screw, but sits against a steel block.... That steel block is secured on the bottom by the stock locating stud and on top by the flathead screw in the breech, located under the barrel.... ALL THREE SCREWS must be in place and tight before the gun is pressurized....

The Ninja SHP Pro regulator is equipped with two burst discs, one to protect the tank from overfilling, and the other to prevent the output pressure from rising about 1800 psi.... This is ideal for our purposes, as those pressures can be reached in a CO2 system, and in fact CO2 tanks are rated at 1800 psi.... As long as you don't disturb the 1.8K downstream burst disc, your QB79 should be just as safe as running on CO2, IMO.... I chose the SHP because of its 1100 psi output (my tanks actually measured at 1200).... Remember I mentioned earlier that the hammer spring in a QB peaks at about that pressure?.... That means that the gun should be shooting pretty efficiently without having to change it.... If you are only running 800-850 psi the hammer strike is actually too strong, and the gun will be wasting air, and may experence hammer bounce.... It still might get lots of shots, but clipping a coil of two off the hammer spring would improve the shot count even further....

Please note, I made NO modifications to the gun in any way.... I did disassemble the breech and deburr it and the bolt and the rear section of the main tube, and I polished up the trigger and hammer and installed a lighter trigger spring and 2-stage plunger.... but those are all fine-tuning details that anyone might do to a CO2 version and have nothing to do with the performance, only functioning and shooting enjoyment.... You have to slide out the barrel to rotate the tank to install it, as the gauge and fill fitting won't clear.... but that gives you the opportunity to deburr the forward section of the breech so it doesn't keep shredding the O-rings anyway....

I think this conbination of the QB79 and the Nnija SHP Pro setup is just about perfect as an introduction to PCPs.... The price is certainly right, and the platform can be modified to your heart's content.... The target style AR2079 version isn't a lot more money, and the conversion process is identical.... IMO, the QB79 and the Ninja SHP Pro go together like bread and butter.... and just in case you might be interested in spicing up that combo a bit, stay tuned as I have a couple of simple mods in order as well....

Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal:
.177 Diana 34, 1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine (Grouse Gun), 2260 PCP Rifle (37 FPE), 2560 PCP Rifle (52 FPE), .22 BAM B-26, .22 BAM B-51, Hatsan AT-4410 Long (70 FPE),
"Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, .308 & .357 unregulated; working on the Mk.III, a .410 shotgun, and .458 cal)

Offline Mebits

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Re: QB79 Ninja - The $200 PCP
« Reply #1 on: July 15, 2013, 07:55:57 PM »
I did exactly this, but had Mike Melick give me a tune for more power. When I got it, it was shooting pellets on CO2 at 686-723fps. When I did the conversion you describe, I was shooting 14.36 JSB's at 800 fps and getting 60 shots.

The best part? I can shoot one hole groups at 20 yds and paintballs are no problem at 40 yds. I've hit very small targets at more than 50 yards and I really have no idea what the maximum effective range is.

M
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Offline supertech77

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Re: QB79 Ninja - The $200 PCP
« Reply #2 on: July 15, 2013, 08:03:25 PM »
great post bob,very informative ' can't wait for the next post on those mod's   ;D  thanks
Hammerli 850 22cal, dual fuel,tuned              R.A.M 25cal, 22cal,177cal tuned 
Walther talon hunter, 22 cal NP tuned
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B-50 177 cal tuned by mike melick
B-50 22 cal tuned by mike melick                        marauder 22 cal 55 fpe,tuned
marauder  25 cal 80 fpe,tuned
Sam-yang 909,45 cal [tuned  by LEROY at B.G.M.F]
shin-sung Fire 201s 9 mm/357[tuned by LEROY]

Offline Ribbonstone

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Re: QB79 Ninja - The $200 PCP
« Reply #3 on: July 15, 2013, 08:33:41 PM »
Bob, you should be the spokesman for this, make a very good argument for the QB79/HPA system and I’ve nothing to argue about.

With shipping included, will be right at $200.  For air use, might be the best introduction to air.

Tank (the custom ones will cost more…this one is ready to go at 1100psi):
http://www.ebay.com/itm/Ninja-Aluminum-HPA-Tank-13-3000-PRO-SHP-REG-1100-PSI-/171066094922#vi-content

(I’ll let ya’ll know if it really comes at 1100psi…ordered one to up-grade a 5mm QB HPA conversion.)

I’ll list a few other things that might not be obvious:

1. The ones converted to HPA use very seldom have valve stem issues.  May &^^& out tomorrow, but at least one of them has run for 4 years on an issue valve valve (did remove the fiber filter, but they tend to shed/disintergrate with co2 use too). Am guessing that with the HPA tank being a closed system (doesn’t have to be opened to refill) and air being filtered/cleaner than co2, the valve stem doesn’t get sliced as often as when using co2.

2. HPA tanks are really slightly under 2”.  Common 9oz. co2 tanks are slightly over 2” (some of the heavy old-school steel tanks are under 2”).  Means HPA tanks are much more likely to fit under the barrel without contact.

3. HPA tankers are generally a bit lighter than the same gun running on co2.  Why? The weight of the co2 tank AND the weight of the liquid co2 inside the tank.

4.  Regulated air is EASIER to tune for.  No need to think of the valve self regulating over a pressure range, the valve sees the same pressure all the time.  Keep that in mind if you have the urge to fiddle with striker spring tension.

5. My serious hunting happens in cool/cold weather.  Co2 isn’t at it’s best when there is frost on the ground and ice in the water.  Air doesn’t really care.

6. May not make a difference to many, but when you are done, have a gun made of wood and metal.  The only plastic parts would be the seals. 

Offline rsterne

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Re: QB79 Ninja - The $200 PCP
« Reply #4 on: July 15, 2013, 08:43:19 PM »
You're bang on with all those comments.... It might be possible to squeek out a slightly more efficient combination of power and shot count by fiddling with the spring preload.... but since the QB hammer setup is so close to ideal at 1100-1200 psi the gains SHOULD be small.... and maybe not worth the bother.... If you stick with 800-850 psi, it's probably worthwhile detuning a bit to stretch the shot count.... I'm planning on two stages of mods.... Upper (post valve) airflow for Stage 1.... Lower (pre valve) airflow for Stage 2.... For Stage 1, you don't even need to pull the valve from the gun, basically all you need is a set of numbered drills and a needle file.... Stay tuned!....

Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal:
.177 Diana 34, 1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine (Grouse Gun), 2260 PCP Rifle (37 FPE), 2560 PCP Rifle (52 FPE), .22 BAM B-26, .22 BAM B-51, Hatsan AT-4410 Long (70 FPE),
"Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, .308 & .357 unregulated; working on the Mk.III, a .410 shotgun, and .458 cal)

Offline Ribbonstone

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Re: QB79 Ninja - The $200 PCP
« Reply #5 on: July 15, 2013, 09:10:10 PM »
Getting away from simple.  QB79 works great with the standard spring, standard striker, and a 1000-1200 psi HPA tank. 


Are ways to get mo' power, but for the average guy, the above would be a good point to start.  Even with no mods, usually see 8 -12% increase in speed simply because air is "thinner" and flows better than co2.

Now I cannot help but to pass one complication on: they are harder to get sealed with air than co2.  Does seem co2 slightly "swells" the o-rings, which helps seal co2. Air is thinner and does not swell cheap (Chinese) o-rings, so air often does have a slow leak.  Most of the time it's the gas block 0-ring(s).

SOME fit and seal just fine, holding air for as long as you'd care to measure.  Others have been real SOB's. Have used several ways to cure that, but for the guy with no lathe and looking for simple, this way has worked.

Bad news is that it takes a WEEK (7 days). Airgunners are NOT noted for their patience.

Get the bare gas block in your hands, with o-rings removed.
Degrease the "shank" (the part that fits into the air tube).
Plug the air vent and both mounting screw holes (can plug them with Al foil).
PAINT the shank with top grade varnish (like the best grade they'd use on boat decks).
Let it dry/cure 3 days.
Paint it again.
Let it dry 3 days
Take out the plugs, put on the o-rings, install (careful not to slice the o-rings when passing over the tube holes for mounting).

It's not much, two thin coats of dry varnish, but it seems to make enough difference to seal the gas block o-rings.

BTW: in my climate, tend to pull the trap door to the attic, and hang the part to dry from the rafters above the central air/central heat unit.  Is a vented attic, so it's warm and dry...pretty good paint box. BUT, it seems some varnish has a liking to UV, so for at least one day, will let it hang where direct sunlight can strike it for at least a couple of hours.
« Last Edit: July 15, 2013, 09:15:09 PM by Ribbonstone »

Offline PackingHeat

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Re: QB79 Ninja - The $200 PCP
« Reply #6 on: July 15, 2013, 10:28:31 PM »
This combo is exactly how my QB addiction began. Throw in a valve tune and it is a deal that can't be beat.
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Flying Dragon - Industry .177 and .22  QB79 w/17ci HPA @1500 psi. w/FM 4-14x44, AR2079A target stock, and a TKO.

Flying Dragon - Industry .22 QB79 w/13ci HPA @1100 psi. w/FM 4-14x44, and a TKO.

Crosman 2240 carbine w/Hipac, TKO, and Hawke HD 3-9x50.

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Offline bradyman1

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Re: QB79 Ninja - The $200 PCP
« Reply #7 on: July 15, 2013, 11:55:05 PM »
Great post Bob. I have been thinking about one of these qb guns for a while.
2013 hunting season totals

                  Me                     9 year old son       5 year old son       Mom
Squirrels.   4.                                   3                       2                 2  
Starlings.   22
Rabbits.                                            1.                                        1
Chippers.      3
Groundhogs.  1
Frogs.            4.                                                          1
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Offline pyroboy33

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Re: QB79 Ninja - The $200 PCP
« Reply #8 on: July 16, 2013, 01:40:39 AM »
This is way cool Bob... ;D. I'll be honest 90% of the time your posts are waaaayyy over my head. But this mod looks like something that I might actually look into  8). Much respect for taking the time to figure this out and share your results with the rest of us.
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Offline rsterne

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Re: QB79 Ninja - The $200 PCP
« Reply #9 on: July 16, 2013, 02:20:18 AM »
Today I removed the barrel and breech to ease the restrictions and increase the airflow.... I did NOT remove the valve from the gun, all mods were made to the barrel and bolt only, plus I installed a larger transfer port seal, from a Crosman Disco/22XX/13XX.... just the rubber seal only, not the metal sleeve.... I got that idea from Tim at Mac1, and it really works great, doing a perfect job of sealing the curved valve to the curved breech, and it's larger than you can go on the porting on a .22 cal barrel....

I drilled out the barrel port one number drill at a time, starting with the #28 (0.140") and ending with the #20 (0.161").... That makes the transfer port 75% of the bore diameter, which is as large as you dare go without creating loading problems for the pellet.... The area for the airflow is a third larger than stock.... I then drilled the nose of the flow-through bolt out one size at a time, starting from the #34 (0.111") and also ending at the #20, so that it was the same size as the barrel port.... That greatly enlarged the hole in the bottom of the bolt where the air flows through, and I used a 1/8" ball grinder tip in a Dremel to smooth and enlarge the slot formed until it was the same area as well.... After careful deburring of the inside of the barrel and bolt using a needle file, I reassembled the top end of the rifle and tested it again.... Here are the results....



The average velocity while on reg. jumped up to 738 fps (17.3 FPE), giving 48 shots starting at 2000 psi before the velocity dropped below 730, and a total of 58 shooting down to 1000 psi.... That works out to 17 psi per shot, and an efficiency of 1.10 FPE/CI.... Starting from 3000 psi, you should get 105 shots down to just under 1200 psi.... This mild mannered gun is beginning to show some real promise.... The Stage 1 mods to accomplish it can all be done with a set of numbered drills and a needle file, plus a rubber seal.... and without removing the valve from the gun....

For the next round, however, I will be pulling the valve out to improve the airflow into the valve, and provide more volume between the regulator and the valve to increase the average pressure available during the shot cycle.... I'm really looking forward to seeing the results....

Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal:
.177 Diana 34, 1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine (Grouse Gun), 2260 PCP Rifle (37 FPE), 2560 PCP Rifle (52 FPE), .22 BAM B-26, .22 BAM B-51, Hatsan AT-4410 Long (70 FPE),
"Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, .308 & .357 unregulated; working on the Mk.III, a .410 shotgun, and .458 cal)

Offline Joseph

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Re: QB79 Ninja - The $200 PCP
« Reply #10 on: July 16, 2013, 03:24:36 AM »
hmmm i just might go this route for my first pcp all though ive also been looking at the bs50/51 from mike
but just over 200? now thats a price you cant beat gonna do some serious thinking now lol
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Online Kailua

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Re: QB79 Ninja - The $200 PCP
« Reply #11 on: July 16, 2013, 03:41:21 AM »
This is way cool Bob... ;D. I'll be honest 90% of the time your posts are waaaayyy over my head. But this mod looks like something that I might actually look into  8). Much respect for taking the time to figure this out and share your results with the rest of us.
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Offline Bruce

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Re: QB79 Ninja - The $200 PCP
« Reply #12 on: July 16, 2013, 09:13:37 AM »
Awesome Job! I keep thinking I might do this with my son qb78. Currently running the remote 48ci tank is fine but be nice to have it more compact.

I figure tank block and 13ci or 22ci tank with 1400psi reg. The gun already has a lighter striker and is setup for 850psi air and 18.1 jsb's start at 709fps and end up at 699fps at about 1000psi were I stopped. I do not have a shot count as I cheated... I fired several stings at the begging and then let air out of the tank to test the lower end. So quiet also at that power level! At 780fps was getting noisy!!!!!

These are great little shooters! Amazing value for the $$$

Bruce
« Last Edit: July 16, 2013, 09:15:18 AM by Bruce »
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Offline Mebits

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Re: QB79 Ninja - The $200 PCP
« Reply #13 on: July 16, 2013, 10:27:47 AM »
It's just impressive to watch Bob work.
When hunting zombie starlings, there are two approaches. The first approach is the "Double-Tap". The alternative is cutting their heads off and putting toothpicks through their hearts.

It's your choice.

Offline willbird

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Re: QB79 Ninja - The $200 PCP
« Reply #14 on: July 16, 2013, 01:32:07 PM »
And I think if I have it figured out right, if you stepped up to the better Ninja regulator, the one that can be ordered 250 psi to 3000 psi you would add about another 40 bucks BUT you would have a regulator that could be run higher than 1100 for some projects. And if you wanted to run it in a carbon fiber 4500 tank for tethered use it would be good to go too.

NINJAREG45X MSRP 98.95

It is just a tad longer than the SHP. Of course the SHP you have a larger marketplace to shop in and that $40 difference might grow a bit in a smaller market. If it is a different thread size and will not swap in with the SHP I apologize for my ignorance in advance.

Bill

« Last Edit: July 16, 2013, 01:38:37 PM by willbird »
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Offline willbird

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Re: QB79 Ninja - The $200 PCP
« Reply #15 on: July 16, 2013, 01:42:04 PM »
When I first started shooting as a kid we used the rifle that one is copied from, or a very similar one. I still remember the low velocity shot and ssssssssssssssss when the co2 ran dry in the middle of your string :-).

I bet they are STILL using those same rifles for that class if I had to guess.

Bill
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Offline rsterne

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Re: QB79 Ninja - The $200 PCP
« Reply #16 on: July 16, 2013, 02:15:28 PM »
Based on previous experience, where I got a significant gain on a 32 FPE QB78 running at 1600 psi, I cut off the flow-through bolt probe, squared off the end of the bolt flush with the back of the barrel port, drilled the bolt and installed a 3/32" diameter extended probe that is 0.10" longer than the original flow-through (because it pushes up inside the skirt).... Whereas on the previous time I did this mod I gained 32 fps, this time I lost 5 fps.... However, the ES seems slightly less (ie fewer high velocity shots).... The only explanation I have for this, is that on the more powerful, higher pressure version, where flow is more important, the thin probe is better.... However, on this version, running lower pressure and half the air volume through it, there is very little difference, and it isn't worth having to use a lathe to make the change to the bolt, simply drilling it out works just as well.... When I increase the power further, I would expect the thin, extended probe to work better, but of course I can't go back and test the flow-through now, all future testing will be with the 3/32" diameter probe....

Basically, either drilling out the flow-through nose.... or replacing it with an extended probe.... work equally well at this pressure (1200 psi) and power level (17 FPE)....

Bill, if you check out my thread on the SHP Pro in the PCP Support Gate, you will note that you can run it at 1500 psi quite easily.... Since anything higher than that won't allow you to use the 1.8K burst disc, which is critical to a safe HPA installation in the QB79.... I don't see the point in purchasing a more expensive reg for this gun.... Increasing the pressure past 1200 psi will require you to increase the hammer spring preload as well, or the velocity will start to drop....
 
Bob
« Last Edit: July 16, 2013, 02:20:48 PM by rsterne »
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal:
.177 Diana 34, 1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine (Grouse Gun), 2260 PCP Rifle (37 FPE), 2560 PCP Rifle (52 FPE), .22 BAM B-26, .22 BAM B-51, Hatsan AT-4410 Long (70 FPE),
"Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, .308 & .357 unregulated; working on the Mk.III, a .410 shotgun, and .458 cal)

Offline Froggy.

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Re: QB79 Ninja - The $200 PCP
« Reply #17 on: July 16, 2013, 05:10:38 PM »
Bob, I'm also converting a qb79 to HPA...I'm considering cutting the valve +- 1/4 inch from the o ring and then to fit a valve spring to the front of the valve stem...this will increase the plenum significantly.
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Offline rsterne

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Re: QB79 Ninja - The $200 PCP
« Reply #18 on: July 16, 2013, 06:05:31 PM »
Way ahead of you.... I suggested that on another Forum 2 months ago, and my gun is currently apart and the epoxy on the 1/4" threaded spacer is hardening as I type this.... I'll have some photos likely tomorrow.... I can tell you that I measured the shoulder that the O-ring sits on, and it's the proper size (9/16") for a #113 O-ring to simply sit in a groove and seal normally, without having to tighten the two halves of the valve together.... There is a long enough threaded portion on the front valve half to get two 1/4" long rings from one valve, incidently (eg. enough for 2 valves).... I epoxied it in place with the correct gap for a #113 O-ring to be stretched into place and will then just slide the rear half of the valve into the tube....

The front half of the valve, with spring, sleeve, washer, piercing pin, and filter is no longer needed.... I will turn a spring seat on the poppet and either drill or install a spring seat on the tank block and simply use a longer spring.... The resulting plenum will be MUCH larger, with unrestricted flow into the valve seat area.... Stay tuned, as this is my "Stage 2" tune....

Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal:
.177 Diana 34, 1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine (Grouse Gun), 2260 PCP Rifle (37 FPE), 2560 PCP Rifle (52 FPE), .22 BAM B-26, .22 BAM B-51, Hatsan AT-4410 Long (70 FPE),
"Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, .308 & .357 unregulated; working on the Mk.III, a .410 shotgun, and .458 cal)

Offline NinjaPaintballRay

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Re: QB79 Ninja - The $200 PCP
« Reply #19 on: July 16, 2013, 06:09:27 PM »
This is way cool Bob... ;D. I'll be honest 90% of the time your posts are waaaayyy over my head. But this mod looks like something that I might actually look into  8). Much respect for taking the time to figure this out and share your results with the rest of us.
                                                                           Cheers
                                                                                       -Caleb C.

X2

X3.  Bob is a genius when it comes to high pressure air applications. 

Bob, thank you so much for doing this review and posting your results.  I'm speaking with several QB owners including @SSS$$$ (^&$@_=s) and his new QB78 and QB79 repeaters he's releasing.  He thinks this will be a perfect solution to overcome the issues of falling muzzle velocity with rapid firing that takes place with CO2.

Very interested to see what else you come up with :)

EDIT-  ODD - I typed the gentleman's name and company name on the post but I have a feeling this forum isnt fond of him.
  • Crystal Lake, IL

GTA - What's been your success with air gun target practice?