GTA
PCP - HPA - C02 Gate => QB-7X Gate -W/Co2 & HPA => : JTK February 16, 2008, 09:22:17 AM
-
QB Mods:
Valve turn down to spring diameter
Spring seat turned on valve
Pin Removed
Alu Piece drilled 6 holes
Washer drilled
Transfer port drilled on barrel to 4mm
Used Paintball pipe as tranfer port seal
Made a 3mm breech riser
Drilled probe to 4mm
Shroud made from alu pipe
2 more grub srews in the breech to hold the barrel
Swapped my 10-40x50 ZOS for a 8-32 Nighteater. Am very happy with the swap as the nigeater stays 100% clear through whole zoom range where the ZOS went fuzzy and dark at high zoom. Also it looks better :) this neccesetated I mill a piece out of the shroud so the scope did not touch the barrel. also milled out a piece so the painball tank does not touch the shroud. Must say QB looks great now and shoots 10fp (jsb's in the 730's)
Mods still to do when I feel like it:
few washers in the hammer spring and
probe replacement mod.
this should get it closer to the 800's I think..
-
Great job and beautiful wrk JT,
You must be proud of all the work you put into that beautiful baby !
What do expect to hunt with that baby now that your getting 10fp out of her ?
Very Very nice job ! Bill
-
I think she will be a perfect pigeon hunter out to say 35 yards or so. We sometimes here get the opportunity to hunt pigeons in silos to assist farmers. I think in that environment she will excel. Nice and light and accurate enough. I may mil a bit more from the bottom to leave more space but will only do so if the tank touching the barrel lightly creates issues.
-
Looks real nice JT! I want to get mine all stroked out too. So far I am pulling 740's in .177 with a regulated 850psi HPA tank. I have done nothing to increase any spring pressures, but I have bored out the bottom of the valve to let the air flow through better, openned the ports, replaced transfer port with ice maker tubing, bobbed and probed the bolt. You can only open up the .177 QB's so much because at some point you are just putting more air out of the end of the barrel. I think the way to do this would be .22, hehe, next project!
-
mmmm.. 740's with hpa.. then I am pretty happy with 730's with co2 when I still need to bob the probe..
-
Yep, yours is doing great. I still have some valve work to do, but I am liking where the air consumption is right now, I don't like pumping:)
-
lol.. co2 rocks in the pumping dept.
-
A real beaut you have there JTK. Well done :)
-
thanks, must say I love it.. Need to do a few more things but I think it is perfect as is
-
It would appear the QB is hold sensative.. Anyone had this with their QB?
JT
-
Does the tank still not touch the shroud when you bench rest it? Usually a little give in the system, which can force occasional contact...and occasional "oops" shots.
Haven't noticed mine being that hold sensitive...they ALL are to some degree, but as far as airguns go the QB's just want a reasonably consistant hold.
-
Hi Ribbonstone.. nope. my home made riser is keeping the two seperated. Anyways.. the only reason I say this is because I got better results when I started to hold it like a springer.. Also. I let my 6year old shoot it today. He is 6.5 years old. 5 shot group at 15m with the gun rested on my hands. :) one went a little low ( about 10mm) the other 4 a raged hole.. (better than I can get..) anyways.. It must be the hold. Anyone getting problems due to recoil from a harder shooting qb(tuned to 740fps with co2)? I think maybe that is some part of the problem. Balance problem when I hold it and fire.. But the gun is for him anyways.. I want him to start hft. Our local club allows the u13's to shoot with a bipod. I can t wait to see the look on the old beards' faces when he starts stacking pellets with a qb @ 6 :) will be one of those priceless moments.