CUSTOM VALVE SCREW KIT for BENJAMIN DISCOVERY - safely allows up to 3000 PSI

Description

This listing complies with eBay's air gun guidelines found here and I will only sell and ship air guns to buyers in jurisdictions where permitted by applicable laws - http://pages.ebay.com/help/policies/firearms-weapons-knives.html
THESE SCREWS ONLY FIT DISCOVERY MODELS. We have other custom valve screws listed for 2240, 2250, 2260, 2300 series, 2400KT, Maximus, Fortitude, Marauder Pistol, 1720T and 1701P.
These screws are designed by Magnum Airpower and custom manufactured, they are not available from any other source. They are direct-fit for Discovery models, no modifications are needed to use them. They safely raise the operating pressure to 3000 PSI.
They are 410 stainless steel heat treated to meet metric class 12.9 with a specified hardness of HRc 39-43. The approximate tensile strength is 185,000 PSI.
The head diameter is .3155", the head height is .0975" and the thread size is 8-32 x 3/16".
The second photo shows just one of these screws holding the valve with 3300 PSI in the tube. The pressure on the gauge is clearly visible in the photo. This is the strongest screw that exists for Discovery models.
DO NOT PRESSURIZE A TUBE WITH ONLY ONE SCREW AS SHOWN IN THE PHOTOS,
A LETHAL ACCIDENT COULD OCCUR.
THAT DEMONSTRATION WAS DONE IN A CONTROLLED ENVIRONMENT WITH PREPARATIONS THAT MADE IT SAFE. ALL THREE SCREWS MUST BE USED TO HANDLE HIGHER PRESSURE SAFELY.
Message if you have any questions, making modifications to your airgun can be dangerous if not done correctly.
Empty all air or CO2 pressure from your airgun before installing these screws or a fatal injury could occur.
Except for the original valve screws, the Discovery PCP tube assembly is as strong as the ones on similar Crosman/Benjamin 3000 PSI models like the Marauder Pistol and 1701P. All are made with the same 1020 DOM steel tubing. All of the other pressure containing components are as strong, the stainless steel Discovery fill adapter is actually stronger than the aluminum one on the PCP pistols. It's safe to use more pressure in the Discovery when the valve screws are correctly upgraded. We have destructively tested this screw design beyond the claims confirmed in the photos.
The screws require a T25 driver, a T25 bit is included as shown in the photo. They are designed to fit the threaded holes very tight when fully installed. The last 1/64 of an inch requires a little extra force to get the screw head snug against the valve. Do not over-tighten, they should be hand-tight using a driver handle. Using a wrench or ratchet can damage the threads in your valve. Standard Discovery valves are a relatively soft aluminum alloy so the valve threads will strip more easily than the threads on these screws. Our custom valves are made of super-strong 7075 aluminum, the holes don't strip easily with those.
The following videos cover
disassembly and rebuild of a discovery as well as installation
of many custom parts. eBay does not allow links to be active so you need to copy the red link and paste it into the address bar above in your browser.
DISCOVERY DISASSEMBLY :
https://youtu.be/woiQMwBbVxs
DISCOVERY REBUILD ( also covers some custom parts) :
https://youtu.be/TqDrNnTGPY8
CUSTOM RIFLE TRIGGER & CASING :
https://youtu.be/uRCkcXnTKsE
The following chrony test results compare a standard Discovery .22 to one modified with our custom parts. 14.3 Grain pellets were used for both tests.
Testing was stopped at 100 FPS below peak power. These first two tests demonstrate the benefits of using higher pressure, it produces a lot more power with less shot-to-shot variance for a much longer shot count. Staying at about a 100 FPS spread, 3200 PSI produced 11 shots more and a 100+ FPS higher peak with every shot above the peak at 2000 PSI.
Unmodified Discovery .22 starting at 2000 PSI :
1)      888.1
Muzzle velocity in FPS.
2)      901.0
Peak power.
3)      899.8
4)      878.8
5)      877.7
6)      871.5
7)      855.6
8)      854.9
9)      849.6
10)    843.0
11)    837.1
12)    836.0
13)    827.6
14)    819..7
15)    813.4
16)    797.1
100+ FPS below peak power, very poorly-balanced shot string.
.22 Discovery with custom valve screws, Magnum Adjuster, wide-bore gauge port, 26" Maximus barrel and a starting pressure of 3200 PSI. The result was a lot more power for a longer and better-balanced shot string :
1)     958.8
2)     965.9
3)     971.2
4)     973.4
5)     977.2
6)     978.9
7)     984.5
8)     991.6
9)     994.7
10)   989.3
11)   997.6
12)   1000
13)   1007
14)   1002
15)   1005
16)   1009
Peak power.
17)   998.8
18)   1002
19)   990.1
20)   982.7
21)   977.8
22)   965.2
23)   958.3
A perfectly-balanced shot string would end at shot 23 or 24 with this specific airgun.
24)   949.4
25)   938.3
Same .22 Discovery with 26" barrel and Magnum Valve. It produced about 10 consistent shots starting at 3200 PSI with each pellet weight tested :
PSI     PELLET   FPS     FPE
3200   10.03 g    1288    36.9
3200   14.3 g      1142     41.4
3200   18.21 g    1086     47.7
3200   25.39 g    1000    56.3
3200   33.95 g     905     61.7
The following chrony results were produced with the same gun described above but with our Magnum Bypass Valve instead of the shorter version and wide-bore gauge port. Both version produce the same power levels. The adjuster was set  3.5 turns back from full spring compression to produce a slightly longer shot string at lower power. The starting pressure was 3200 PSI. JSB Jumbo Monster 25.39 and Jumbo Beast 33.95 produced the best consistency and groupings of about a dozen types and weights tested. Heavy pellets work best at these power levels :
1)    817  FPS    33.95 g
50  FPE
2)    833
3)    837
4)    843
5)    845
6)    850
7)    853
54  FPE
8)    849
9)    838
10)  824
11)  816
50   FPE