My 177cal QB78s comes in on Tue, what to expect velocity wise ?

[wll2506]

Have not been home yet to test my QB78s in 177, but I'm so impressed with the quality, that I bought another one for $63.99. Have a few QB's but I'm very impressed at the price point and the stuff that can be done with them. This plastic stock is just made for rough and tumble use !

wll

[wll2506]

Got home and she is shooting the same velocity as yesterday along with nickel size accuracy at 15+ yards and no, the pin in the valve did not puncture the Co2. I will try two different things tomorrow ---- hope one of them works.

This is getting ridiculous, I should have taken the gun down correctly the first time !

wll

[wll2506]

I'm  sitting at home and I start to do one of the things I was planning on doing tomorrow. I took the silver section out and put in 1/2 of the felt in to use as a guide. Put the gun together and kept playing with it, I cooked the gun and shot and did that a few times, then all of  sudden it had a different sound, one of where the hammer hitting the valve sounded like the piercing pin was moving more. I put a canister in the bottom and a empty on top and tightened her down and she filled :-)

I got 13 good shots that averaged 605fps, that is 23 fps more than I was getting before shooting the same 10.5gr pellet. This gives me about 8.5fpe at the muzzle and about 5.8fpe at 35 yards. That is enough, but I still would like another 10-15 fps, will see what I can do ? Taking out that felt piece would be great if I could get the piercing pin to stay in place.

Till tomorrow,

wll

[lefteyeshot]

You need to branch out a little. I have a .177 AR2078 thumbhole and a .177 AR2078B side lever target model. They shoot about 600-650 fps as I remember. Haven't shot them in awhile. They come with some little extras. Better barrel, sights, barrel weight, extra rear sight, better scope mounts, de-gassing port and tool. Nice wood stocks. Test target from the factory. Nice looking guns.

[wll2506]

You need to branch out a little. I have a .177 AR2078 thumbhole and a .177 AR2078B side lever target model. They shoot about 600-650 fps as I remember. Haven't shot them in awhile. They come with some little extras. Better barrel, sights, barrel weight, extra rear sight, better scope mounts, de-gassing port and tool. Nice wood stocks. Test target from the factory. Nice looking guns.

Tim,

They sure are I have two QB79's. Below is a pic of one of them. I use them exclusivity for target shooting.



wll

[lefteyeshot]

Nice gun.

[Toddspeed]

I got 13 good shots that averaged 605fps, that is 23 fps more than I was getting before shooting the same 10.5gr pellet. This gives me about 8.5fpe at the muzzle and about 5.8fpe at 35 yards. That is enough, but I still would like another 10-15 fps, will see what I can do ? Taking out that felt piece would be great if I could get the piercing pin to stay in place.



wll

Last time I shot my QB78S on CO2 I was getting 635fps with 16 grain AA pellets, I got about 20 good shots on one cartridge. And that was at about 60 degrees. I’d say from my experience that changing out the breech seal to the Crosman Discovery breach seal is the best way to increase fps. Second would be opening up the flow through bolt probe. But, the QBs come way over sprung, so if you don’t cut a coil or two from the hammer spring you will be wasting a lot of CO2.

[wll2506]

I got 13 good shots that averaged 605fps, that is 23 fps more than I was getting before shooting the same 10.5gr pellet. This gives me about 8.5fpe at the muzzle and about 5.8fpe at 35 yards. That is enough, but I still would like another 10-15 fps, will see what I can do ? Taking out that felt piece would be great if I could get the piercing pin to stay in place.



wll

Last time I shot my QB78S on CO2 I was getting 635fps with 16 grain AA pellets, I got about 20 good shots on one cartridge. And that was at about 60 degrees. I’d say from my experience that changing out the breech seal to the Crosman Discovery breach seal is the best way to increase fps. Second would be opening up the flow through bolt probe. But, the QBs come way over sprung, so if you don’t cut a coil or two from the hammer spring you will be wasting a lot of CO2.

I assume your gun is 22 cal / mine is 177. Yes I do need to change the breech seal to a Crosman !


wll

[Toddspeed]

Yes, mine is .22. I’m no airgun scientist like many here are but, I figure if I can get 20 14ftlb shots on one CO2, you should be able to get more shots with your .177, even if you do get the FPE up to 650 or so.

[Toddspeed]

By the way William, I sure do love my AR2079b, it looks just like yours. Even more now that I have a regular size scope instead of the compact one in the pic below.

[wll2506]

By the way William, I sure do love my AR2079b, it looks just like yours. Even more now that I have a regular size scope instead of the compact one in the pic below.

Nice gun  yes those guns are real nice guns for sure !

wll

[Model25]

My QB78 Deluxe in .177 was purchased Dec 2016. The bone stock rifle averaged 641FPS at 74 degrees while using the standard weight cardboard box Premiers. It averaged 666FPS using the Crosman pointed pellet, also at 74 degrees. The Premiers averaged 613FPS at 64.7 degrees. 3.01 fps pr degree ,30.1075 pr 10 degrees
Data was taken with a Fluke dual channel thermometer and a Pact clock.
Have fun with it, Mike

[Ribbonstone]

Just counting the ones owned (a few more for friends),  think there were 9.  If you count a couple of Beeman Chiefs, then make that 11.


The old ones (like +10 years ago) were usually hit or miss for accuracy.  Lot of QB tricks in the archives, not all of them were just about powering up….some actually dealt with accuracy/stability.

Count 1 “miss” out of 11 factory barrels...and the miss was a real old QB78s (like 12 years ago). 
Count 1 “exceptional” barrel that is actually “match grade”.
Count 9 “good” barrels that ended up needing a b it of TLC.

Haven’t found speed to really help.  Does change what pellet they like, but not the actual group size….so even at 600-650fps, they shot something well (it’s often not what you would expect them to shoot well….but the barrel has the veto-vote.

Even after all the tricks, did have to condemn one barrel as hopeless (on a really early one).  Re-barrel one to 5mm, but the take off barrel was good and got used elsewhere.
--------

The take off  barrel from that 5mm conversion got machined from the breech end and used on a Talon SS….shot just as well, but no better.   Then it got cut  (from the breech end)to a carbine and fitted to a 2260 HiPac….shot just as well.   Then cut to pistol length (again, from the breech end) and used on a 2250 pistol.   

Can’t say the accuracy really changed.  Was always “good”...never “great”….pretty much unchanged as to group size, but did change which pellet shot best.



Looked up old data forem out-the-box type tests.

Pretty close to 9 foot pounds for the .177's and close to 10-11 foot pounds for .22.  Can reverse that to figure velocity for the pellet weight, but co2 has always favored heavy pellets moving slow over lite pellets moving fast....co2 is a "heavy" gas and seems to much prefer heavy pellets to make better use of that slower gas expansion.

[lefteyeshot]

If I'm understanding you, same barrel didn't do well in several different gun. Wonder what the one thing was caused that. I had an old B4-2 Peak under lever would not shoot any pellet well. My other Peak and Bam guns were tac drivers. The one difference was pellets fit a little loose in that gun.

[Ribbonstone]

Got that right...was “good" when on the QB…. was working on the breech end and leaving most of the rifling and muzzle alone, wasn’t much difference.  Pretty much avoided the whole crown, coke vs no detectable coke issue.

Shot equally well regardless of what it was hung on….which is a pretty good indication of the barrel’s ability rather than what was using it.

Not a guy who thing  “pretty” bright polished crown makes any difference to a “good” crown...have never seen where polished make a rat’sarse...makes it pretty, but it’s not really any better.


Too many other factors bore a B4-2 (springer)…..barrel might be fine, the refile itself is just so hard for the shooter to shoot well.

[wll2506]

Man it is cold and windy out here. I set up a few big solid oranges at 26 yards and sent a pellet right through each one so I figure I'm good for HOSPS and Starlings at that range. The wind is bad enough that I have to sight in 2 inches to the left and the hits were still a bit to the right.

And you ask, "How do you like the synthetic stock" --- well I really do like it alot, it is tough as heck, it is very comfortable and if need be I could use it as a smashing tool :-)

The wind now is really howling, so I'm heading home.
----‐‐‐-----------------
Once I get home I empty the rest of the Co2, take my long screw driver, unscrew the valve and remove the small piece of felt that I left in to make sure the piercing pin was centered ----- well, what I did not realize is that the bottom Co2 is not pierced by tightening, it is pierced when the hammer hits the valve stem and that stem drives the piercing pin up to pierce the Co2, and that is exactly what it did.

It charged up to speed with two dummy shots, and i then went for testing and chronographing. I got 22 good shots averaging 575fps +- 4fps ! It then started to drop.. I was extremely happy.

I still have not decided if I want to take the gun apart and change the breech seal to get more velocity, I will have to think that one over after more shooting. Right now as I stated before I use one Co2 as I rarely shoot 15-20 shots on an outing and I'm happy with that.

I still want to make a dummy solid Co2 to see if that gives me a few more shots or more consistency. If I can do it Monday I will.

Pic of QB78s as I have her set up, outside in the wild today. I'll be heading out tomorrow to fulfill my shooting Jones for sure :-)



wll

[AndyKunz]

That's pretty good, especially the consistency.

What pellets are you shooting at that speed?

Andy

[Ribbonstone]

Plastic stock isn’t bad on the single shot version...will swap with the wood stocks.  Cheek is a bit low, but just about the same fell as the wood stocks.  From trials, the 78S, AR2078, (thumb hole), AR2078A, 78D wood, 78D plastic, Beeman 1085 (repeater)...basically all the 12gr. Rifles...will swap stocks.

Not true of the various PCP versions….not only the gauge, but the diameter of the air tube.

On the repeater version, the cheek ends up way-low...the odd barrel band has to be moved a bit forward as the other stocks aren't inletted for them...ends up.more like a chin rest; taller breech isn’t all that much taller, but enough to really notice.

Put the plastic stock on an old QB78 PCP conversion….just seemed right for one that gets out into the woods/rain/mud more often.
DSCN3078 by Robert Dean, on Flickr

[wll2506]

That's pretty good, especially the consistency.

What pellets are you shooting at that speed?

Andy

Shooting 10.5gr CPUM's -- a good heavy weight pellet with a pretty good BC :-)

wll

[wll2506]

Ribbobstone,

That is a very nice rifle, bet it shoots great. ---- 22 cal or 177 ?

wll