Canadian Airgun Forum

as most of experienced the QB is an awesome gun but has a crapy valve when it comes to the valve end pericing pin hole its off centered and has a dfficult time pericing the main front bottle also the screen in side and felt also cause premature break downs in the valves as well,

fix 1 remove the felt and then screen and toss in the garbadge
Fix 2 use a lathe if you got one or a decent drill press so you can drill dead centre the hold on the fornt of the valve body to 7/32 size , now this will solve these 2 problems.
the next fix will be fix 3 take the washer out of the valve and goto the hardware store with it and the pericing pin front end valve and find the same size washer but with a hole in the center of it the same OD as the percing pin that also will allow for free travel of the pin.. you dont want any jam up spots on the pin movement. getting an exact fit is best so that the hole will keep the pin dead center... the washer thats in the valve its hole is way over sized and does contribute to the pin hitting off centre as well..

as soon as i can get more brass and bronze i will be making new front ends for the valves in both hammer pericing and full bullk fill only front ends ,, the new bulk fill front ends are much shorter and allow for more co2 gas volume in the tube as well..

It's only becoming off centered if the piercing pin is not put back
together aligned with the washer because the washer should
kept it centered all the time.

true the felt & screen are junks, it was copied from the old Crosman but
those two elements are also help to keep the piercing pin centered.

This actually happened to me, infront of a witness from the Forum. He had brought over a QB-78 Valve, Brand New just outta Plastic Bag. Just wanted to make that clear, and it hadn't been installed in the Rifle as of that moment. Ok, we had taken it apart, and I was checking the "Valve Screen" out and it totally dissintagrated/unwrapped itself in between my fingers. I'm going to myself O-Shyte, now I'm gunna have to replace it. There was no problem there at all as he had witnessed what had just happened. What's up with this happening I couldn't believe what just happened. Any thoughts of what happened here. My hands were clean with nothing else on them. Even so if there was, it's a Brass Screen from what I saw of it. It went into lines of wire, like it unthreaded itself right in my hand. Nor was I doing anything to it other then just holding it between my fingers. It actually fell apart before it hit my two fingers...

Michael...

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We will never be the Man we once were, but what we will Become...

well i cant see how the washer hole can keep the pin aligned when the inside hole on the washer is 3 times or more the diameter of the pericing pin, not to mention if you spin the valve body up in the lathe its very aparent that the hole in the valve front is off center as well.. so inlarging the hole in the front valve body can fix the problem easy enough then getting the right size washer that has the right size center hole will keep the pin aligned and keep it that way properly...

iam not saying all QBs have the problem just every one so far that i have come accross and several others i have heard about .

I have to agree with you to apoint on this here. But, I haven't heard of any complaints as of yet, maybe just lucky. But I also did notice the hole abit large for the pin to travel through. But my main concern at that moment was the Screen. But you know this would be a good idea to construct abetter front for the Valve itself outta Brass. I want to get one of these QB-78 eventually. I almost bought a QB-79 but didn't know it was in .177caliber at that time, plus afew other things came up. I really wish I would have just bought the QB-78 when I had the Coin for it, Damn. I had alittle joke pulled on me, no big deal though, it all werked out. But I'd most diffenently want one of these Valve Halves you making after I get the QB. It's got a great Bolt in it, and shoots right down to the last drop of Co2, I couldn't believe that one, but true...

Krazy Mike...

_________________
We will never be the Man we once were, but what we will Become...

Yes, perhaps it's isolated incident with the certain variant of the QB's.
I just haven't seen one yet over the last three years.