My new QB78 Deluxe

[Brutuz]

Bought a .177 QB78 last week. As you might know I like Crosman's very much and this QB78 being a copy of the Crosman 167 it has been appealing for some time and when I had the funds I bought one.

Performs fine out of the box. Having worked on several 13xx'es and 22xx'es I wanted to tweak this one too and got a lot of usefull tips and a sealkit.

I'm leaving the valve alone.

Changed the trigger spring,
replaced the breech seal,
did some de-burring,
enlarged the probe port hole a bit,
fitted a new probe o-ring,
polished the friction faces of the hammer unit,
fitted an additional hammerspring which is .25" compressed,
fitted a do it yourself dove tail rail to accomodate my Airforce bipod
after the last mod, the hammerspring, fitted new barrel o-rings and (again) a new breech seal

It barks a bit more now.

Pitty I don't have a chrony.







Take I
Take II
Take III additional hammerspring / 10 m shooting and shotcount to follow

Am very happy with this airrifle, the way it looks, how the bolt action works and sounds, the power, the accuracy and.... great value for money.

There's only one minor issue. As soon as the powerlets have been pierced the tube is under pressure. As soon as the power has gone and you want to change the powerlets it's not possible to simply unscrew and let the remainig CO2 escape. You have to dry fire it untill it's empty. Maybe I'll buy the tube kit including de-gassing key shown on Archerairguns.com in the future, hope someone in the UK sells it.

[Poacher]

I've had a couple of 79's and a 78. Biffo tuned mine - great bloke. They are great rifles, light, good handling and reliable power wise. Shame the seals don't seem to last very long. I still have a QB79 out on loan to my mate's Grandson. Somehow I don't think I'll be seeing it again

[jetski]

don't buy the degassing tube and key. making your own is easy. you just need to drill a hole in the tube in the right place. making a key out of a hex key or screwdriver is also very simple. there is a thread with a plan uploaded on ukchineseairgunforum ill try and find it, it explains how to do it. I can't remember who put the photos up but he was offering to make the keys free of charge

[Brutuz]

Thanks Jetski, found the pics and "how to"

[jetski]

that second vid is well put together, great music, lol

[Brutuz]

Thanks Jetski

Just uploaded Take III (as promised)

[ame="http://www.youtube.com/watch?v=EUFVEg6BB3g"]YouTube- QB78 Deluxe Take III[/ame]

[Brutuz]

Yessssss

I've got a Chrony 8)

Here are the results


(RAF / rate of fire)

Do need an indoor light fixture for shooting after dark..

Will take it apart again and pollish again, this time using a powertool.

Will also remove the extra piece of hammerspring to check the difference.

[Brutuz]

Last night's string had a few errors due to bad lighting.

Made my own light fixture using plain 40W bulbs and a piece of aluminium strip.

Did a 16 shot string last night so it was still charged with CO2, had a few errors first emptying last nights powerlets but soon figured the height of some shots was causing that.

Emptied the gun, loaded 2 new powerlets, dry fired twice and had dinner.

After dinner I shot this error-free 50 string using the 7.1 grain H&N Hollowpoints:



(No alterations on QB, only had time to make the light fixture)

[Brutuz]

Two 10 shot targets to show the grouping and 10 shots on the Chrony using a more common grain pellet:

QB78DL take 4

[Brutuz]

After tweaking the valvebody:



boring vid: