My QB79 on 1500PSI

[BigTinBoat]

Finally got around to going thru my QB79 I picked up from AGD. My reverse bottled 78 is getting a new .25 barrel from Roy at Mountain Air so I needed to get the 79 done with it's .177 barrel so that I have a .177 bottle gun.


Here is what I did to the valve. (That's the valve for my 78 I reworked in the background)




Need to change the bolt o-ring as I'm getting some air out of the bolt but here are the preliminary #'s.

RVA              7.9                 10.5                      13.4
3 turns        580 (5.9fpe)
4 turns        710                 560                       530
5 turns        820                 683                       639
6 turns        920 (14.8fpe) 794                       720
7 turns       1000                896                       829
8 turns       1020                937 (20.5fpe)       874 (22.7fpe)
9 turns       1024                945                       880
10 turns     1026                947                       883 (23.2fpe)

Looks like the "Optimal" tune should be about 6.5 turns with the 7.9's and 7.5-8 turns with the 10.5's and 13.4's

[SpiralGroove]

Hey BTB,
1) Which pellet shoots best in the gun?
2) What long......conical spring did you use in the QB79 Maxi-Valve?
3) Where are you getting your tank blocks from?  I need to buy two and nobody seems to have them for a fair price with shipping.
4) Good Work .

Kirk

[BigTinBoat]

Hey BTB,
1) Which pellet shoots best in the gun?
2) What long......conical spring did you use in the QB79 Maxi-Valve?
3) Where are you getting your tank blocks from?  I need to buy two and nobody seems to have them for a fair price with shipping.
4) Good Work .

Kirk

1) Not sure as I was only shooting 3' (over chrony and into trap)
2) The spring is from ebay. Company is 32 Degrees (but other paintball companies put their name on them too, see link below)- Spyder 9pc Spring Kit I used the long black one and cut it down to fit.
http://www.ansgear.com/Warrior_Paintball_9_Piece_Spyder_Spring_Kit_p/warspyder9pcspringkit.htm
3) My block came on the gun, it's a standard 79.
4) Thanks - can't wait to see if it picks up with the bolt o-ring. I used the extended bolt I made for my 78. The o-ring was getting worn so I tried to replace it. Not sure which o-ring I used though. The 004 I couldn't get on, but the metric on I used this time seemed a bit loose and thus it's leaking. Will have more time to fool with it this week. With working till 5PM I don't have any daylight left when I get home to test accuracy.

[BigTinBoat]

Hey BTB,
1) Which pellet shoots best in the gun?

Well I was able to get outside today, even with the 15mph wind. Target was set at 25yards.
Looks like the gun likes all of the JSB's in the wind the 8.44's actually did the best, but it was gusting on and off so not 100% sure.
Looking at the top right, where I shot the 10.3's you can see my "horizontal" movement with the wind that's why I shot a 2nd group with them.



Gotta love the Winny domes though. Good thing I had the 2 targets together or I would have thought all 3 shots went thru the same hole. I stopped after 3 shots and didn't go to 5 like the others.

And here is the gun with the 78 stock I cut down, inletted sanded, stained and Truoiled.



After shooting it I went inside and de-tuned to just over 18FPE.
Filled to 3000 and let my fill hose attached so I could use the big Wiki gauge for measurement.
Shot 28 CPUM's and I was down to 2500psi. The average was 880 FPS so the efficiency was a dismal 1.13.
I then shot 28 of the JSB 10.34's and gauge was on 2100psi. These averaged 888fps for 18.1fpe and an efficiency of 1.41. I'm happy with this.

[SpiralGroove]

Hey BTB,
Very Nice Work
Looks like you'll get 80+ shots per fill.
I don't think the efficiency on my QB's is stellar , but at least I get a decent shot count.

What scope is that - a Hawke Sidewinder?

What's nice about the QB's is they're so light you can put almost a 2 lb. scope on and the gun will weigh 7.5 lbs. total .   

[BigTinBoat]

Hey BTB,
Very Nice Work
Looks like you'll get 80+ shots per fill.
I don't think the efficiency on my QB's is stellar , but at least I get a decent shot count.

What scope is that - a Hawke Sidewinder?

What's nice about the QB's is they're so light you can put almost a 2 lb. scope on and the gun will weigh 7.5 lbs. total .

Yep I think 80-90 is about right.

No way I got that kinda coin for a QB scope. It's a Simmons 44mag 6-21 x44

It is a very light combo

[pllagunos]

Coming in from the AirgunNation forum, thanks Rob for this information amazing job! What would you think of installing an ar2078 stock in the qb79? I found some pictures of custom qb's in 2078 stocks and they look gorgeous as a HFT airgun.

[BigTinBoat]

Coming in from the AirgunNation forum, thanks Rob for this information amazing job! What would you think of installing an ar2078 stock in the qb79? I found some pictures of custom qb's in 2078 stocks and they look gorgeous as a HFT airgun.

Thanks
It would be a "Love/Hate" relationship for me. I would Love the way it looks, but Hate that I would be able to shoot it "right".......I'm a lefty.

Apparently they only even made one version of an Ambi Thumbhole stock and there aren't many of those out there. (Can't afford any of those custom ones)

[HappyHunter]

Apparently they only even made one version of an Ambi Thumbhole stock and there aren't many of those out there.

Very true. The only place I've seen that carries them (replacement stocks) is ScopesAndAmmo here in Canada.... http://scopesandammo.com/storefront/product_info.php/industry-brandshanghai-airgun-ar2078le-thumbhole-stock-p-835

Unfortunately though, he won't ship to the U.S...

[sr1sws]

Looks good.  My bottled QB79 in .177 is set to shoot AA 10.3 at about 825fps.  I only fill to about 2100psi (as I fill from SCUBA) but easily get 50+ shots on regulation.  In fact I've never tried to figure out just how many I might could get.

I made a half-shroud for mine to tame the noise.  No "guts" to the shroud other than a Marauder-style stripper.  The QB is maybe a wee-bit less accurate than my Marauder with a carbon fiber stiffened barrel. It's much lighter than the Synrod, fun to shoot.  I used ball nosed spring plungers (http://www.mcmaster.com/#standard-spring-plungers/=zytmrj) to emulate a 2 stage trigger - works good!

Have fun and Happy Thanksgiving!
Steve

[BigTinBoat]

Took off my homebrew LDC and put on a piece of CF tubing. I basically put the same internals inside the 6" of CF tube that extends beyond the barrel. It's just as quite as my Crosman's with TKO's.
The CF tube cost me $20.66 delivered for (2) 500 mm pieces. The internals cost just pennies. Could have done it with just one, but added 2 small pieces to cover the entire barrel. It's 46" oal now.