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PostPosted: Mon Apr 06, 2015 10:57 am 
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rsterne wrote:
You don't need to pull the barrel out of the breech to replace the breech seal.... While you're at it, throw away the stock seal and use one from a Crosman 13XX or 22XX.... just the rubber seal, not the metal sleeve.... It's a perfect fit, conforms to the curved valve and breech, and is larger with more flow....

Bob


Forward screw is under the barrel. Barrel has to be removed.

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PostPosted: Mon Apr 06, 2015 12:15 pm 
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I put plenty of dielectric grease onto the 3 small Orings to go on the end of the barrel. Figure it may slide right out without the need to twist the barrel around (as was the case when I first removed it). Hope that this mean the o'rings won't be damaged as I don't have any spares. Should they become wrecked is there a place in town I can buy these?
Hope to find the time to get started in a couple of hours, especially now that wife took a few blank shots with the gun and I could the smile in her face. This is already beginning to pay off. This is one great looking, nicely functioning gun.
Thanks for all the assistance.

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PostPosted: Mon Apr 06, 2015 12:21 pm 
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Hi Tech Seals, for all your seals there Joolz.

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PostPosted: Mon Apr 06, 2015 12:42 pm 
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Awesome, thanks for that. Would be heart-breaking if I had to place an order online, if it came to that.
As for using the seal from a 2240, I'll try it for the next time, if it will improve flow. But won't that mean less shots per session?

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PostPosted: Mon Apr 06, 2015 5:13 pm 
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Done and Done!!

Installed the breech seal and it shoots beautifully. Quiet and easy to handle, given it has a nice balance. Working that bolt is a treat. Feels like the bolt from a powder burner, I could never get tired of it. Loading pellets is a snap and for once I don't complain that the gun lacks a magazine (like the 953, crosman 1077, M4-177). The clicks the bolt makes, the pressure needed to push it and lock it in place, all a treat and a joy to work. At first I dismissed this gun as a nuisance given it requires a couple of CO2 canisters. Boy, was I wrong. This is a must-have for anyone's collection. I have to thank a member here for passing it on to me for close to nothing (thanks Andy!). Rifle is in perfect condition and the date on the inside of the stock reads 2012 so I'm assuming this is a new build. My first time tearing apart a rifle and so grateful to the members here that helped. Made what seemed like a daunting task a snap.

Which is why I plan to add a couple more tips in case someone stumbles upon this page.
The main thing I can recommend is making a valve removal tool from a socket. A large screw driver simply won't work - and they don't get much bigger than the 24" monster I bought for this occasion - which proved useless. That valve is there way too tight. Some seem to have succeeded with some sort of a blade but modifying a socket takes but a couple of minutes. A hacksaw and a vise is what I used, really simple. And a couple of extensions for your ratchet. In my case I used an old, rusty 13mm socket that fit inside the tube perfectly with maybe 1mm to spare.

For twisting apart the valve body use a blowdryer to heat it up, as already mentioned in this thread. An allen key inside one of the holes will provide good leverage.

The dielectric grease only cost $5 at Can Tire (near the automotive section). I used this pretty much everywhere, on all the gaskets, inside the bolt body, safety button, tube etc - in very moderate amounts.

I only replaced 5 seals, the two large o'rings (valve body and tube end cap) and the three smaller ones on the barrel. The kit comes with 4 other tiny ones but I didn't see the point in replacing these. Pressure is holding up nicely, taking a break from a 40 shot session. Bet it will give me 60 strong shots.
Since it has fibre optics I will likely put a scope on it although the pellet feeding port may become tricky to load pellets with a scope - will see. Not the worst fibre optics but not great either. These were easy to dial in.

Super happy with the latest acquisition. Guess this makes me one step closer to the elusive PCP craze.
A big thanks to all that helped.

Useful links:
http://www.gatewaytoairguns.org/GTA/lib ... 8_Tune.htm
http://co2airguns.org/qb78-tuning-2/qb7 ... uning-kit/
http://flyingdragonairrifles.org/indust ... eluxe.html - for owners manual.
http://www.fairsales.pwp.blueyonder.co. ... akdown.pdf


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PostPosted: Mon Apr 06, 2015 5:19 pm 
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Congrats on your repair and tuning of your QB!

You have dared to go where I would never feel comfortable going.

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PostPosted: Mon Apr 06, 2015 5:54 pm 
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Now add a QB HiPac to your rifle and a hand pump
Can do bulk CO2 with it as well :-))

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PostPosted: Mon Apr 06, 2015 6:32 pm 
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Quote:
Forward screw is under the barrel. Barrel has to be removed.


Carp!.... I forgot that, it's under the loading port.... :oops:

Sorry....

Bob

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PostPosted: Mon Apr 06, 2015 7:29 pm 
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Voltar1 wrote:
Now add a QB HiPac to your rifle and a hand pump
Can do bulk CO2 with it as well :-))


You mean, a way to make it into a pcp? That sounds interesting. Btw is it common to have to dry shoot the QB some 40 times in order to empty out the CO2 once it begins to drop off? It seems to take forever.

One mod that I think would make me happy would be a .17 barrel. Can't say 22 pleases me that much. Probably can get more shots per sessions too, how those lighter pellets wouldn't require that much of a push to go flying out. Any idea if these are available? I'd imagine all that's needed is a barrel and a smaller bolt pin?

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PostPosted: Mon Apr 06, 2015 7:50 pm 
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rsterne wrote:
Quote:
Forward screw is under the barrel. Barrel has to be removed.


Carp!.... I forgot that, it's under the loading port.... :oops:

Sorry....

Bob


:-))

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PostPosted: Mon Apr 06, 2015 7:53 pm 
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.22 is more efficient than 177 due to bore diameter. Larger makes better use of the push available.
Bolt could be made and barrel fit but costs dollars.......
Maybe a friend stateside could get you a setup from Archer Airguns down there. He won't ship to Canada....

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PostPosted: Mon Apr 06, 2015 8:22 pm 
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Place a wanted ad for a qb 177 barrel and bolt. I'm sure someone here will have them kicking about. If not, Eric at scopes and ammo sells them.

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PostPosted: Mon Apr 06, 2015 8:39 pm 
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I'm looking forward to the BNM repeater breech.

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PostPosted: Mon Apr 06, 2015 8:56 pm 
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Voltar1 wrote:
.22 is more efficient than 177 due to bore diameter. Larger makes better use of the push available.

Had not considered that. If it decreases the number of usable shots drastically than I'd shy away from the idea. Wonder if anyone in this forum has tried a .17 barrel on their QB and know that number.

Reason why I'm considering this is that using .22 for target shooting isn't that fun as I just came to realize. Not only does it destroy the target but since the pellet doesn't imbed itself into the duct seal more than maybe halfway, it makes things a bit messy once you hit a few too many on the same spot. Also surprised by the cost of .22 pellets.
Since I don't plan on shooting at things alive I see no benefit to having a .22.
Will consider it a bit more and see which way to go. Scopes and Ammo has the .17 barrel but apparently it lacks the open sights. Not that there is much of a loss with these fibre optics sights. But yeah, before I spend big bucks on one will post it here in case someone has one kicking around or is interested in an exchange.
Thanks

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PostPosted: Wed Apr 08, 2015 12:19 pm 
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rsterne wrote:
to replace the breech seal.... While you're at it, throw away the stock seal and use one from a Crosman 13XX or 22XX.... just the rubber seal, not the metal sleeve.... It's a perfect fit, conforms to the curved valve and breech, and is larger with more flow....

Bob


Please clarify the above. Are you're saying that the seal in the pic I posted above (what the manual calls breech gasket) can be replaced with one of a larger diameter from a 2240? And this would allow for more flow, meaning a few more fps?
Here's my problem: getting well over 120 shots per session. That's about double what I understand one should be getting out of a pair of CO2 canisters. Since I don't have a chrony it's hard to tell how many fps I'm getting but I can tell that it isn't all that much. For instance, from 6m away a .22 pellet will only inbed itself halfway into the duct seal. I know it's a rather unscientific way to measure speed but that's all I have to measure it by. That and the audible delay between the muzzle sound and the sound of the pellet hitting the trap.

If the seal I'm using is that restrictive I'm all for replacing it with one of a larger bore. Heck, I'm even considering drilling the one I have to see if it improve fps although I fear I may ruin the only gasket I have. Where can I find the 2240 seals? Preferably a place that doesn't charge $25 for a minimum order for an item that may cost a couple of bucks.
Thanks.

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