GTA
PCP - HPA - C02 Gate => QB-7X Gate -W/Co2 & HPA => : tolly November 27, 2008, 04:28:16 AM
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Hello, I'm trying to remove my QB78 deluxe barrel to give it a clean, I,ve taken off the stock and undone the barrel band and slid it up the barrel. Then i've undone the barrel set screw "2800" but theres something stopping me from being able to pull the barrel off.
Any idea's anyone?
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Haven't done a QB Deluxe, but I'm assuming the barrel is notched where the barrel band screw goes through, you'll probably have to completely remove the barrel band screw, not just loosen it. Hope this helps,
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if you have the barrel band completly off,
you may have to give it a good pull because the Orings sealing the barrel might be holding it in pretty good
just a thought
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Open bolt makes it a bit easier, but generally the o-rings are going to catch and cut on a burr raised by the set screw. Once it's off, deburr the inside of the reciever ( a bit of fine emory paper on a spinnning shaft will do the trick...just slot a bit of wooden dowl or Al. rod to make one). KEEP IT CLEAN...no grit left behind. After that, the barrel goes in and out a lot easier.
Unfortunately it's "normal" that the o-riongs get buggered up when taking the gun apart the first time...barrel o-rings or valve o-rings, they all see to catch on some sharp edge/burr and get a nick/cut. Do the deburring once and the new set of o-rings will last several disassemblies.
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cheer's guy's, i'll try it again now. I did have the barrel band all the way up near the muzzle of the barrel and i had the bolt open and the set screw was out. i'll give it a good tug this time. I didn't before as i thought i had done something wrong becasue i could only turn the barrel a couple of degree's left and right before it was being stopped by something.
p.s thanks for the info people, you will probably see me asking a fair few more questions over the next couple of weeks as i'm trying to do everything myself and im only 18 and whenever i seem to take stuff apart i can never but it back together again :)
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done it now, was just about to give up, then looked at where the breech joins the barrel and saw it had moved 1mm so i got my dad on the other end of it and pulled it apart
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Sorry I'm late to this discussion, nut I understand the issue. The first time I removed a QB78 barrel I thought I was doing it wrong because I had a "tight" one, then I gave a good heave and the barrel came out of the breech very rapidly - of course I wiped the greasy end of the barrel right across the sleeve of a nice clean shirt. Oops!
I'd like to second the "fit new O rings" comment made by an earlier poster. They will certainly be damaged by sharp edges during removal and if you replace the old ones you will probably have leaks around the breech/barrel interface and this will reduce muzzle velocity. Wipe some air tool oil around the breech end of the barrel or some other non-petroleum-based lubricant (including the O rings) before re-inserting.
Stephen Archer
Archer Airguns Inc.
http://www.archerairguns.com