The QB78 C02 Pellet Rifle A User S Text, photos and illustrations by George Fox Lang An introduction to using the classic QB78 pellet rifle, one of the nicest and most popular C02 rifles ever produced. The QB78 is a svelte sculpture in steel and hardwood sold at a bargain price. The SMK QB78 Deluxe C02 Rifle utilizes a double charge of 12 gram cylinders. Features include single shot bolt action, rifled barrel, hi-vision fibre optic sights, gold coloured bolt and trigger, hardwood sporter stock, manual safety, and single stage adjustable trigger.
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- Instruction Manual For Smk Xs78 Qb78 22 Cal Air Pistol
| QB78, 79, AR2078, AR2079 PCP Conversion |
| To remove the safety lever must first set it to the 'S' Place a block under the module trigger and safety lever rod knock. |
| After knocking out the safety lever. |
| Unscrewing the lock nut from the bottom of the barrel to hardwood stock. |
| After separation. |
| Separating trigger casing assembly requires unscrewing two screws. |
| Removing the barrel |
| Unscrew the screw compression strap. |
| To unscrewing use allen key, size 2.5. |
| Remove the barrel of a strong, firmly, pulling along the barrel. |
| After removing the screws of the trigger assembly remove plugs from the casing tube and breech. |
| The separation of housing/body |
| Under the barrel, after removal, there is a bolt connecting two tubes of the body/housing. |
| To remove the breech bolt put back Allen key. |
| Dismantled components tube and breech. |
| Removing the valve |
| Unscrew the screw and unscrew completely locating screw for fastening hardwood stock. |
| Pushing the valve is possible in many ways, for example by pushing it through the hole in the tube with a screwdriver. |
| Disassembly the valve |
| When reassembling, change the spring. |
| Tuning Step 1 (optional) |
| Tuning to vastly increase the muzzle velocity and power of your QB78 air rifle! Muzzle energy increases from about 25 ft/lbs for a .22 caliber gun. Muzzle energy increases from about 22 ft/lbs for a .177 caliber gun. |
| Step 2 |
| Valve dimensions change You should change the dimensions of the indicated elements - use a lathe or a drill and sandpaper; the effect is big enough when you are able to put a valve into a tube. |
| Charge valve |
| Tube assembly |
| QB78 PCP Warning: maximum pressure should not exceed 200 bar |
This is a genius kit as with the QB78 deluxe it’s a great gun but notorious weak in power not 10 ft/lbs as stated by SMK. This kit has been developed which increases the power to over 11ft/lbs. You no longer use CO2 capsules as this adaptor allows you to fill the gun using air so converting to PCP. You MUST READ and follow the instructions as provided with the kit. DO NOT FILL OVER 120 bar by doing so you risk damaging the internal seals. This kit is universal and works on .177 and .22. We recommend that a qualified gunsmith fits this kit.
Contents:
1 x CO2 to PCP air valve conversion adaptor (as above)
Spare Seals
1 x Transfer Port seal
You are supplied with everything you require inc spare seals and also an instruction leaflet. CO2 to PCP air valve conversion has been tested and held at a pressure of 200bar then set the valve with thread adhesive. It is safe to use at 110 to 120bar maximum otherwise damage will result to valve seats, seals and structure of the gun.
A Transfer Port seal provided will withstand the higher working pressure and must be fitted at the same time as the input valve to avoid seal leakage, gun damage and produce reliable results. The firing valve will be good for many shots if the pressures are not excessive.