Canadian Airgun Forum

QB78 I would like to start upgrading
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Author:  AirForceAddict [ Tue Oct 31, 2017 4:48 pm ]
Post subject:  Re: QB78 I would like to start upgrading

Princess Auto sells a kit of springs. ... -p3801008e

Author:  bigHUN [ Tue Nov 14, 2017 11:10 pm ]
Post subject:  Re: QB78 I would like to start upgrading

Most of the CO2 to hpa conversion-upgrades are done on my QB.
Started with a repeater kit from archersairgun, then I modified the valve assembly, increased the cylinder volume to the max, the next step is playing with hammer spring tension...
The speed and consistency is pretty much got to a level of my expectations, a regulated 800 psi input gives a 730-715 fps range with a 18 grain pellet, a little higher I was planning to... because two 1500 psi regulators in my way from aliexpress...I will probably have to do some shim work to take it down to 1200 psi.
The air consumption is a next step I want to take care. I need more springs to play with hammer overall, I saw some picture about some modding the hammer spring tension with an external screw, will see if I would want to go that way...Noticing also some minor air leak as well probably from the valve assembly seals, tinkering now about some tool because I completely remodeled the valve assy aluminum part and doesn't exist anymore, so how to tighten that oring there inside on the brass valve body...I never saw any of this work lay down on the table only internet pictures, so takes me some time to tinker how I can do things on my own in my basement.
I decided to go with external airtank instead of the front/below mount. The bad is, that the coiled hose is way to stiff and want to pull-torque the front of the barrel. So, planning to migrate the air connector - fill from front to the back and below the handgrip.
Trying to figure out the fittings, one to connect to front bulk fill plug 1/8 NPT, to make a 180 degree turn, then a steel hose inside the plastic stock to lead all the way back to the handle grip bottom face. And a second fitting back to check valve connector. Steel hose instead of a copper tubing for car brakes maintenance from crapytire.
So looking into, where to get a 50 cm steel tube, and how can I bead the two ends? Not sure about any plastic hose can live up to a 1500-1800 psi pressure and still need to install the fittings on both ends.
Anybody did something like this?

Author:  wesb2007 [ Wed Nov 15, 2017 11:44 pm ]
Post subject:  Re: QB78 I would like to start upgrading

You can buy macroline and macroline fittings, which are made for paintball, and then some 1/8npt elbows. I've actually got some I'm not using but I'll have to check how much macroline I have left. Are you here in Canada? I noticed you said you bought the repeater breech from archer airguns and many have mentioned he won't do any business with Canadians whatsoever.
You could probably go to your local paintball shop and get some macroline as well and macroline to 1/8npt fittings.

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