90 duro orings for 78 barrel?

90 duro orings for 78 barrel?

Joined: September 10th, 2005, 11:38 am

February 24th, 2011, 9:15 pm #1

has anyone tried using 90 durometer orings on the 78 barrel? will they strech enuff to get over the barrel into the oring grooves? my 70 duro's get eaten up pretty bad every time i take it apart. Thanks, Dennis
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Joined: December 24th, 2006, 2:06 pm

February 24th, 2011, 9:31 pm #2

I've got LOTS of QB spares, bought 'em in bulk. All are 90-durometer nitrile.

They still get chewed up, even if you're careful. The aft two rings have to pass over the barrel set screw hole and the very last (aft 0 ring) must pass over the transfer port, these holes are what chews up the O-rings. De-burring the edges of these openings inside the breech helps, but they're only gonna make maybe one undamaged trip over the openings. Use lots of lube and replace at least the aft two rings every time the barrel comes out.
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Joined: May 2nd, 2006, 4:27 am

February 24th, 2011, 11:43 pm #3

has anyone tried using 90 durometer orings on the 78 barrel? will they strech enuff to get over the barrel into the oring grooves? my 70 duro's get eaten up pretty bad every time i take it apart. Thanks, Dennis
second set screw and toss the o rings with two set screws on the barrel the o rings are usless as they are not needed to seal the transfer port. I have not used  barrel o rings in years on QB's.

www.richinmich.com
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Joined: February 25th, 2009, 1:05 pm

February 25th, 2011, 1:22 am #4

Mod from the UK Forum and don't need to remove barrel when taking out the breech. It uses M5x10 counter allen.


Link > scroll to bottom >>>http://ukchineseairgunforum.myfreeforum ... asc-40.php

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Joined: May 2nd, 2006, 4:27 am

February 25th, 2011, 2:14 am #5

a mod I did three years ago, don't use that any more I just cut the barrel flush so i can make it fit the breech bore nice and snug and make a seperate pellet tray it works much better and the barrels are easy to machine.

www.richinmich.com
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Joined: July 28th, 2006, 9:40 pm

February 25th, 2011, 8:47 pm #6

I've done the second grub screw mod and it improved accuracy with no more left to right POI variation, and gets rid of the barrel band. I also drilled through breech for allen key use but filled the hole again as found pellet damage. That separate pellet tray sounds good but how do you fit it for easy removal.Is it delrin?
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