My take on my new QB79

Joined: August 3rd, 2015, 11:39 pm

December 18th, 2015, 2:30 am #1


Well, I have finally had time to really shoot my new QB79. I am really impressed. It's no where near as powerful as my Disco but I didn't buy it for that reason. With the bottle filled to 3,000 psi, I can shoot over 120 regulated rounds, and they ain't slow, I have not chronied it yet, but it is pretty zippy. I mounted it with a Sniper 3-9x32 scope, a real shorty and will be adding a stud for a bipod. I have it dialed in at 30 meters. SQUIRRELS BEWARE Thank you, Stephen.


I have been wondering though...how do you guys think this will work with a regulated valve from JDSAirman at 1400 psi ?
Instead of the 1100 I have now. happy. . you know, for a little more distance and maybe a little more umphhh !
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Joined: December 14th, 2010, 5:08 am

December 18th, 2015, 5:54 am #2

i have mine set at 1400. It's a .22 and gets over 30fpe with the heaviest pellet i have
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Joined: August 3rd, 2015, 11:39 pm

December 18th, 2015, 4:40 pm #3

Really ? Wow, did you go through JDSAirman ?
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Joined: March 28th, 2002, 6:54 pm

December 18th, 2015, 5:57 pm #4

Well, I have finally had time to really shoot my new QB79. I am really impressed. It's no where near as powerful as my Disco but I didn't buy it for that reason. With the bottle filled to 3,000 psi, I can shoot over 120 regulated rounds, and they ain't slow, I have not chronied it yet, but it is pretty zippy. I mounted it with a Sniper 3-9x32 scope, a real shorty and will be adding a stud for a bipod. I have it dialed in at 30 meters. SQUIRRELS BEWARE Thank you, Stephen.


I have been wondering though...how do you guys think this will work with a regulated valve from JDSAirman at 1400 psi ?
Instead of the 1100 I have now. happy. . you know, for a little more distance and maybe a little more umphhh !
even for the same power, which would require re-tuning. As soon as the reservoir pressure drops below your output pressure, the gun comes off the reg, and might as well not have one.

Were it my gun, I'd tweak the tune rather than buy a higher pressure reg, but I'd chrono the gun first. My experience is that 930 fps isn't that much more useful than 870(likely your most accurate velocity)since the trajectory and wind drift are only slightly improved, but shot count takes a big hit.
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Joined: March 11th, 2014, 1:20 am

December 18th, 2015, 8:04 pm #5

Scot - from reading your posts you have much more time/knowledge in AIR gun tuning then I, but I don't think this is quite true in all instances. Especially if you were to tune at the highest power for the lower PSI.

If I tune a gun to shoot say 16FPE at 1200psi and this is the MAX I can get out of it, I think my upping the PSI to 1500 I can use less air per shot (for the same 16FPE) and thus get more shots from 3000 down to 1500 then I would using more air going from 3000 down to 1200. I think this is especially the case then you are dealing with a smaller valve volume.
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Joined: March 28th, 2002, 6:54 pm

December 18th, 2015, 8:35 pm #6

(small valve volume, max power tune at low pressure)you might not give up anything by raising the reg setpoint some, and could even gain a little efficiency. Things like pellet weight, caliber, and barrel length might have significant effect as well.

I do feel that pushing reg pressures too high, as a band aid fix for poor valve dynamics, is a bad idea, so I tend to discourage that.

I don't think there are many ironclad rules with no exceptions.I should be clearer when I'm making generalized statements, and state them as such.
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Joined: March 11th, 2014, 1:20 am

December 18th, 2015, 9:27 pm #7

Scot,

No problem. It's nice to see that when I bring something like this up, you confirm it......means I'm learning something.

Thanks
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Joined: March 28th, 2002, 6:54 pm

December 18th, 2015, 9:37 pm #8

The good days are when I learn something that puts a new perspective on something I thought I understood completely.
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Joined: August 3rd, 2015, 11:39 pm

December 20th, 2015, 10:07 pm #9

even for the same power, which would require re-tuning. As soon as the reservoir pressure drops below your output pressure, the gun comes off the reg, and might as well not have one.

Were it my gun, I'd tweak the tune rather than buy a higher pressure reg, but I'd chrono the gun first. My experience is that 930 fps isn't that much more useful than 870(likely your most accurate velocity)since the trajectory and wind drift are only slightly improved, but shot count takes a big hit.
For sharing your ideas and knowledge.
That being said, . I fill up my tank to the max of my scuba (tops 3000 psi) so I get over 100 regulated shots. Slightly lower as more fills. It really shoots just about everything pretty good, except for those Gamo pointed expanded. The Gamo TS22 s drop awful quickly but are still patterned well. As I said , I have not chronied it yet. Hopefully old Santa will help me out.
If I decide to start tuning, where do I start ?
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Joined: November 14th, 2015, 5:30 pm

December 31st, 2015, 9:54 am #10

Well, I have finally had time to really shoot my new QB79. I am really impressed. It's no where near as powerful as my Disco but I didn't buy it for that reason. With the bottle filled to 3,000 psi, I can shoot over 120 regulated rounds, and they ain't slow, I have not chronied it yet, but it is pretty zippy. I mounted it with a Sniper 3-9x32 scope, a real shorty and will be adding a stud for a bipod. I have it dialed in at 30 meters. SQUIRRELS BEWARE Thank you, Stephen.


I have been wondering though...how do you guys think this will work with a regulated valve from JDSAirman at 1400 psi ?
Instead of the 1100 I have now. happy. . you know, for a little more distance and maybe a little more umphhh !
My 79 is shooting great and shooting CPHP pellets. I do need to chronograph her to really she what she is doing. Have the NINJA SHP valve and tank in this gun so I'm getting 1100psi regulated per shot.

I love how light this little gun is, and of course the amount of power it has, a great little hunting gun, although a bit loud. Just ordered a Umarex moderator for this gun and that should work great, just have to make it look cool ; - )

wll2506
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