QB co2 posts

[Ribbonstone]

Came to my attention that there are some poor lost souls that actually read the QB co2 posts when I post them.  Could be a bit of ego, but do get responses.

A couple have been wondering about the low power thing.

Simple...i’m not well, hung up my car keys, have good and bad days,  and can’t get out to the  more open spaces to actually put higher power airguns to what they were made for.  Wife’s too afraid I’ll croak in the middle of nowhere.

So I shoot in the back yard on good days, where power isn’t needed, and write many more posts than I use to.

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 Today, a good day, was the return of the 5mm QB.  Finally got it to all QB factory parts. The original 78S skinny stock back on, pure QB78 QB valve/spring. Put back in a soft/squishy transfer port (which is why it’s down around 10.2 foot pounds) and reunited with a cheap China “tech force” scope.

DSCN0293 by Robert Dean, on Flickr

For the time frame, always thought that QB stock had at least an interesting color and grain.

Changes from standard are an HW 5mm barrel, bolt adapted to 5mm, and a too large LDC. That’s it, could swap everything else for any QB you have.

Stimulated to shoot it today by looking over my 5mm pellet stash (any 5mm pellet is hard to find today) and decided sitting on the old ones like a chicken on an egg isn’t doing me any good.

DSCN0291 by Robert Dean, on Flickr

So the top two, boxed Cr. Premiers and the old tin of JSB’s, needed to be shot against new JSB’s (which I also can’t buy right now...but at least they are current pellets). 

Always wondered how Crosman could label the pellets as both 5.5MM and .20 caliber….too late now, but was it just too much to ask to change the print to match?

I just refuse to measure groups, other than visual, on “rip paper”. It’s waste of time.  For scale, the green dots are ľ”.  Fully aware that I'm a little shaky at the bench, so this isn't the best someone else could do.

DSCN0289 by Robert Dean, on Flickr

The two JSB’s look the same, are the same weight, shoot about as small a group, but group POI slightly different.  The Crosman are worse groupers, but backyard useful at short (25 yard) range

[OTmachine]

Always enjoy and appreciate your posts!  Thank you!

[Ribbonstone]

Like “Cracker Jacks” use to be...once you got the colored coating (tinted poly spray?) off the old QB 78s types, never knew what you’d have. Use to call it toe-nail-polish finish.

Usually you’d find lite wood, wood putty filling some cracks, and visible knot holes.  But once in awhile you’d get a surprise.  From taking the butt plates off and looking at the arc of the tree rings, were harvested from small diameter trees of less than great quality (from the cracks and knot holes).

Big plus for the 78D’s stock.  Larger, more adult sized, and the rubber butt pad really makes standing it up more secure than the old hard plastic butt.  They pretty much “evened” the quality/grain of the wood.

Same rifles, other than the larger barrel diameter, so likely most of the slight extra money was from the better stock (even in China, a bit better wood cost a bit more). Shot the same so far as I can tell.

[Goose]

I enjoy your posts, Robert.

It was by looking up what you'd done with your co2 guns that I was able to get mine shooting as well as they do.  The current .22 I have out performs (accuracy-wise) the original that I got from Tim.

Plus you're the only other person I know of that has had one in 5mm. 

Stay safe,

J~

[real7]

Hey Ribs, I always enjoy your posts. After you posted about the QB quite a few years ago, I had to have one.
 It may have been after a post titled “The boys of Summer”.  Being in Pennsylvania it definitely is my summer time gun and truly enjoy just grabbing some pellets and cartridges and going for a walk about.

[Ribbonstone]

That is what the QB78 does best, no matter the caliber/power...we are adaptable.

Have 4 other QB's running on QB barrels that I'm accuracy-happy with...no intention of changing out those barrels. One PCP conversion to .25 (LW barrel).

Would be a long time before I ever got “boon dock” ready, and I’m eyeballing the large stash of .25 pellets I haven’t been using.  Thinking I need to reconvert the PCP to .25 12gr. rather than sing  “Auld Lang Syne “ to a pile of pellet tins every New Years.

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Find the absolute best conversion is not stocks, power up grades, PCP converions....it's converting full tins of pellets to empty tins of pellets with an accurate rifle.

[farrlarr]

I enjoy your posts; it is always good to find CO2 posts.  I think the QB 78 is the best bang for the buck that is out there, although mine is labeled Tech Force 78 Gold rather than QB 78D.

[tennx]

Like all I enjoy/appreciate the wisdom u share…Im a simple old man…and I like my guns simple…I like the simplicity of the 3 QB’s I have…I leave them stock and count on u folks to help me keep them running…many thanks
All fitted with various vendors LDC

Ar2078-.22
OB deluxe-.22
QB 78S-.177 (quietest and my fave..)

[Ribbonstone]

The CO2 QB’s are really easy to figure out..about as simple as it gets.

Just for fun….the current crop of QB’s. Some got fancy, most are just plain-Jane., some run on air, some run on co2.  Appreciated the simplicity from the start, still do.

 DSCN0167 by Robert Dean, on Flickr

Newest one missed the group photo:

DSCN0264 by Robert Dean, on Flickr

The above takes care of anything that needs to be shot between 60 foot pounds and 6.  I should have stopped here and not bought a bunch more airguns, but the “lure of the new” is strong.

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Before the worst happens to me, am going to take a large QB “dump” of opinions/tricks. 

If looking for power tips, am going to disappoint...I gave that up, really not something I want to do with QB’s unless you start some serious mods (both to the valve and mods for safety). Am perfectly happy with normal co2 speeds/energy and perfectly happy with the QB trigger once adjusted by the provided screws.

If you need more power, give up co2 and just buy a PCP.  Are several low priced PCP’s on today's market (the Storm-rider might be the best combination of features for a walk-about PCP).

OVER ALL:

1. The new versions (bought one last year and missed the group picture) are much cleaner machined, better fit internally, and (at least the one I got) burr-less.   With a better blue, would be as good as the old Crosman 160.

2. I’m perfectly happy with  normal co2 speeds/energy (12-15 foot pounds), so gave up “hot rodding” both co2 and HPA.

12gr. QB’s:

1. The issue poppet is soft.  At first, will be cursed by blown valve stems/poppets. Know I was lucky to get a factory poppet to last a year or two.

2. 12gr. Co2 is the only air gun system that requires us to open up the gas tube every time, then we inject two objects into the tube, and close it back up.  Being meticulously clean stopped the early poppet deaths. 

3. The end cap o-ring tends to swell.  Swelling goes down after a time, but if you are in a rush to reload 12gr, it can be a fight.  Better o-rings swell less.

Bulk fill Qb78's:

1.Dealing with fittings, hoses, large tanks, fill manifolds....a whole lot of extra "snit"... like  tank filling a PCP...but some people like the idea.

2. Can be cheap if you use big industrial sized tanks..cheap on a co2 cost per ounce basis.   If you use paintball tanks, may as well use smaller paintball tanks buy a QB79.

CO2 “tanker” (QB79’s):

1. Only a good idea if you have a good friendly co2 fill station near at hand. If you do, can be the cheap way to run a QB.

2. SMALLER tanks make the rifle more handy.  Hard to find any small tanks, even the 9oz co2 tanks are hard to find.

3. Be sure you can find the right tanks, and the right filler, before going “tanker”.

(I’d often use little 3.5oz tanks on the QB79.  That’s the same as 8 12gr, just in a compact package.)

HPA: most commonly converted QB79's:

1. Just like a PCP, have to have a way of self generating 3000psi to fill a 13cuin HPA bottle (which is about 215cc’s).

2. Air wants to leak where co2 doesn’t.  Probably a matter of co2 swelling o-rings more than air does.  Often an o-ring fight to get them to actually hold air long term. 

3. Cheap 850psi HPA bottles have not been a problem….only one  died, and it lasted 8 years before it did.  The one on the AR2079 is coming up on 10 years.  Even if I just junk it, call it $5 per year.

4. Thinking the low pressure out put lets the regulator live longer. Considering how regulators work and the seals, that makes sense to me (and in real life, the higher pressure  HPA bottles once used all had regulator problems a lot sooner than the low pressure ones).

5,  I do tend to keep all the HPA’s to 850-900psi outputs (the cheap tanks aren’t too exacting), which is enough for 12-15 foot pounds (Caliber dependent)....basically less rifle stress than hot weather co2, just that HPA would provide for the same energy in the cold.

6. All the HPA  rifles in the above pictures are basic 12 foot pound rifle (both the .177’s and 22’s) running on normal QB valves.  All of them could be adjusted for more of less power, but at 12 foot ponds get 200 really equal velocity shots on a fill.

7. Do NOT be too impressed with 200-2010  shots per fill...it takes 215cc’s of air from 3000 to 850 psi to do it (not real efficient).

8. The 200 shots per fill NOW seems excessive to me...I don’t have a 200 shot walk-about to do and even in back yard plinking, it now seems excessive.  For me, it’s more like fill it once, don’t fill it again for weeks or months.


GENERAL:

1.The grab-and-go , well handling rifles, great for  back yard shooters and walk about rifles, are the 12gr.  co2 rifles.

2.. If you want swap  back and forth from HPA to co2 tanker, the 850-900 out put HPA rifles are pretty much  correctly tuned for co2 as well. 

3. There is a weight concern, balance concern ,with tankers (co2 or HPA) away from the bench in real walk-about shooting. Front bottle mount or reverse bottle mount, the weight is still there

4. Besides style, front or rear mounted bottles depends on if you want to hold a fat metal tank in your off hand or a wood stock with the tank ahead of it. Can see which I picked.

5. Reverse tank blocks are custom (expensive) parts to find/use….one of the mods that kind of voids the “simple” philosophy of QB’s.

[Acapulco]

Still a favorite of mine after buying my first QB in 2007.  Something about the easy use with the Co2 guns & pistols... I've enjoyed shooting throughout the years.

[Ribbonstone]

Will have to wait until I am appointment free and have a few “good days” in a row.

Standard QB’s will “top swap”..the uppers (receiver, bolt, barrel) just swaps on and off to one complete lower (everything in the lower gas tube, including transfer port).
So I’ll pick one lower, and top swap a .177, 5mm, .22, and .25 uppers.  One lower would be the same tune, pretty much the same release of co2 per shot.

Would be pretty predicative of the  bore area size in energy generation (not velocity..energy), and actually doing it is somehow better for me than estimating it.

Would result in a massive re-sight in project once the uppers are put back on their normal lowers, but I don’t care...any reason for shooting is welcome at this time.

[Ribbonstone]

(posting on your own post is like talking to yourself)

Almost….and it’s my fault it failed.  Did not follow the rules...used my new spare parts without replacing them...so I ran out of “good” QB  parts.

Had just enough old QB parts to put together one “lower”….old parts, the valve stem looked a little funky, but tired it any way.  100% QB, unmolested valve, striker, issue striker spring...would shoot like any out  new QB out the box QB.

Got the .25 upper correctly working on the new 12gr. lower, but the funky old valve stem poppet blew on the first shot (gas down the barrel has to be poppet).

COULD switch to a new Delrin poppet, but the whole point of doing this was to see what a totally issue QB co2 system would do in .25 and compare that (by top swapping) to all my other uppers (.22,5mm, .177).

EXPECT  about the same amount of co2 injected into the barrel to follow the area rules.  It’s the SI in PSI (square inches to push on)….but I might be surprised.

Gave up...in a bright spot, order a new valve and a new poppet, then ordered 75 12gr.  Considering my medical issues, consider it a bright spot as I wouldn’t order them unless I expected to use them up.

[OTmachine]

Delrin, Pet-P, Peek, some of the harder teflon, or ??.  What is your preference for valves?  I think I have one of your sketches around here.  What would work best?

[nervoustrigger]

If I can nudge into the conversation here, any of the materials you listed will do nicely for CO2, with the possible exception of PEEK.  It's so incompressible that it can be tricky to get a sufficiently good finish to prevent it from leaking, but if you have some experience with surfacing and/or lapping a poppet to get it to seal, by all means go for it.

Teflon is the softest of the 4 materials you listed so it's the easiest to seal.

Any of them should last indefinitely at CO2 pressures, provided no contamination gets in and gets lodged in the seat or scratches it.

And any them will be substantially easier to knock open than the spongy OEM poppet.  The heavy hammer and beefy hammer spring of the QB is already overkill so plan on reducing the hammer spring tension and perhaps also lighten the hammer, else it will waste a lot of CO2.

[Ribbonstone]

What we tend to do is make the new poppet "sleeker" (better air flow) than the squared off original.  If we made two new ones of the same shape, the differnce in "lift" has a pretty minimal effect....it's there, but it's not all that much.

Jason is right...the harder material is also harder to get to seal, esp. at the low pressures (co2 or the HPA I'd recommend for a Qb79 conversion).

NOT going to do it for the .25...whole idea was to see what a standard QB  valve, striker, striker spring would do in .25.-----------

Pretty confident I know the direction of change. If I top swap .177, 5mm, .22, and .25’s…...just not how much change with co2.

Did do a simple top swap with a Chief...un changed lower, just changing the upper (breech/bolt/barrel as a unit).

Low speed tuned PCP...but I expect the direction of change to be the same (more energy as the base area off the pellet increases).

DSCN2827 by Robert Dean, on Flickr

If you want to guess what a 10.3 foot pound .177 co2 QB would gain in enregy with a simple top swap to .25, have plenty of time to guess….the ordered factory original parts are going to take awhile to get here.

[Ribbonstone]

Last echo...did get it kind of done.

I’m careless...and a bit stupid.

The front action screw of a repeater Beeman 1085 got mixed into the parts I used for the 12gr tube and I didn't notice.

It’s longer...it impinged on the valve stem….the  poppet wasn’t bad, was just not allowed to close because it was rubbing on the too long front action screw. That delayed valve stem closing, and let all the co2 squirt down the barrel.

Changed to the right screw.

Still, don’t have a fully original QB78 lower and can’t find an original “squish” transfer port. Did the best I could with what I had by adjusting to where the .177 was as slow, but the parts are not quite the same as all original.  Couldn’t find an original transfer port that wasn’t aged hardened to useless.

And I don’t have a full length .22 barrel (both had been cut to carbine/16ish length) so I skipped the .22 test.

Set it up for the normal 9ish foot pounds with a .177 upper (21.5 in).  Then tried the long HW .20 upper (22” barrel)….then the .25 LW barreled upper (22.5”).  So there is a 1” difference in lengths.

Really no surprises here….just confirmation of what we all expected.

DSCN0296 by Robert Dean, on Flickr

I promise to do it all over once I get a standard factory valve and find an original transfer port, but this pretty well went as predicted for a polly port.

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The .25 now looks even more long-nosed with the huge LDC and without the long air tube. 

DSCN3078 by Robert Dean, on Flickr

DSCN0295 by Robert Dean, on Flickr

It’s about as “handy handling” as it looks, but nearly 1/4th the energy and a lot quieter for back yard use.

Don't get nuthing for free....more energy, more gas use...fewer shots per fill.  This one seems to be doing 34-37 good (not slowing down) shots.  for 2X12gr.

[BC81]

Hey Ribs, do the repeater models fit in the wood stocks? The newer one, like the 1085 or whatever it is. I have an old walnut 160 stock I could drop one in.

[Ribbonstone]

You kind of can put a QB78 stock on a Breeman 1085 repeater.

The front barrel band is unique in that it is taller ( the repeater brecch has to be taller) and it has a big square lower section to provide a 2nd stock screw.

With no insetting, will work in a QB stock if itithe big square bottom barrel band is placed ahead of the foreand...just enough room for the end cap to screw on and off.

DSCN0115 by Robert Dean, on Flickr


HAve tpo say...I really didn't like the repeater.  The mag was as cheap (and wonkY) as mags get....the higher breech makes all stocks "cheekless" hold.

[BC81]

Interesting... I may need to get one just to put in this lonely stock. It has good enough grain to be refinished and used.

Does the 1085 take the typical mods the QB78 does?

[Ribbonstone]

Not quite...they changed some of the striker system the “cheap way” in order to get the repeater part to work.

Cheap because they used the same parts as a QB78...just modded them.

DSCN2834 by Robert Dean, on Flickr

The same striker, they just drilled and tapped a 2nd threaded hole behind the regular QB78 pin hole (#6 #5).

It’s the same part # 4, they just don’t need to put a pin in if. Basically it serves as a spring gulde and a spacer.

#3 is a plastic spacer...and the rear end cap is the same.

They used standard QB78 air tubes, which have the same QB78 slot in the tube for a pin in #4..even though there is no pin