+7 years QB HPA conversion

[Ribbonstone]

Just "Chinese junk", at least to many shooters.  Even WORSE, " low-powered Chinese junk".

Just posting as a reminder, there is at least a small segment of shooters that do not see power ad the anser to all the QB questions.

Haven't seen this one in awhile...I've neglected it too long, but got the urge to take it out today and see if it "went stale" from dissuse.

Put together about 7 (maybe years ago...still running fine.  Did have to change an o-ring or two, but nothing that wouldn't have been just as likely to happen to any PCP over that time.

Not to most poster's prefernce, designed around 12 foot pounds, but it certainl has been trouble free running on 850psi output.  Likely less stress from pressure than running on co2 and cleaner gas.



80 shots used up just a little less than 1000psi, so a full fill (3000-850psi) would give about 175 shots per fill. Thats pretty inefficient. Something like 1.1 fpe/cuin.

I've left it that way, even though there is likely another 20-30 shots that could be extracted from it with enough mods.

Shoots well, at least with pellets it likes:






The mysteries of grouping:

1. Have mentioned that some rifles are just terrible with the long 21gr. piledivers. This is amoung the worst offenders.  Other rifles/other barrles shooting slower and faster have done better (which wouldn't take much considering 40% of the shots are randomly tumbling). To add to the oddness, the BEST out of 13 rifles tested with that pellet also wears a QB barrel.

2.Have to chalk up the left/right and high/low group centers to vibration.  Generally slower'heavier land lower...except the 8.4's kind of ruin that observation.

 Guess the point of this is that a converted QB doesn't have to be a "stop gap" way of moving into air.  Several PCP's have come and gone for various reasons...QB still has a place in the safe.

(Although I may ruin that by trying to eek out a better efficiency at the same energy....trying to get to 200  12 foot pound shots.  Have done that with a .22, but the .177 doesn't use air quite the same way.)


So it may take some time, but likely many of you will eventually reach the conclusion that MOST of your daily shooting would be better served by lower power, quieter, more shots per fill airguns.

EDIT:

Then again, maybe not.  Mom was 81 when she bought a new Hemi-Charger and it wasn't until she was 85 that she (claimed) to always keep it under 100MPH.

[Atomic Powered Gruds]

12FPE in .177 is what I am aiming for right now. I should be getting an older QB78 and am pondering where to start. I can tell its been modded already lightly if nothing more. I have a 24oz CO2 bottle I might use thought its quite big for the task and would likely need to be on a hose. HPA is what I am aiming for though I'm going to go for what ever is most cost effective to start out with.

I want to keep it around 12FPE mainly for how many shots it will get and not needing heavy expensive pellets to keep the speeds down for tighter groups. I love JSB and there heavy(always one of the best for me) but at how I like to plink my wallet hates them thus I'm always out of them. Hoping if I put enough good work into deburring and polishing everything from barrel to sear maybe CP/Daisy might work well enough for plinking/ close range pesting.

I know every rifle has its likes and dislikes but what pellets have been good for your QB?

[Ribbonstone]

Odd as it may seem, 850 of air shoots a bit faster than co2, even with all the other things kep the same. While air isn't exactly "thinner" it helps me to think of it that way, so with air at a hoped for 12 foot pounds it's better to have the valve cycle faster (basicly open/close quicker to let less air out).  So if you do tune up a .177 QB to give 12 foot pounds on co2, likely will have to retune it down a little to get 12 foot pounds on air.

HPA rifle shown didn't start that way, it just kind of evolved in that direction in steps over a period of a couple of years. Wasn't what I planned on as much as how it evolved to suit what i was doing at the time.

Same rifle as above, just that it started out as a 12gr.



Then a bulk flll.

Then just teathered to a 20oz. paintball tank for bench shooting. Did cobble togeter a little rest with a cradel for the 20oz. co2 tank, and so long as I wasn't walking around and just nailing set up targets, didn't find it too restrictive



Then a tanker co2.  Liked the teathered version above, but moving around in the woods and spending whole days out shooting  Bulk fill could have worked if I caried something to re-fill the rifle.  Converted to tanker and started using the little co2 bottles (those are 3.5oz. tanks) and carriing a spare in my pocket.

(sorry, no picutre of it wearing a little co2 tank....but it looked just like the HPA picture, just the 3.5oz tank being shorter (and no protursions to keep you from just spinning one off/one on).

About then, got the urge to try HPA when I had some dissapointments using co2 in the cold (or what passes for cold down here in S. Lousiana)...which leads us back to the first post.

Didn't set out with any plan...just followed the best/simplest way to get it to do what I wanted it to do.

[nervoustrigger]

I know every rifle has its likes and dislikes but what pellets have been good for your QB?

The .177 QB barrels haven't been too pellet fussy, at least those I've dealt with made in the last 3 years or so.  However invariably it has been some weight of JSB or Air Arms that has grouped best.

AA 10.3gr, 5 shots at 25 yards shot just two nights ago:


Same rifle shooting AA 8.4gr at 43yards.  The red dots are 3/8", same size as an aspirin.


A different QB shooting the JSB 10.3gr at 25 yards:


Yet another rifle shooting AA 7.3gr at 25 yards:




And lastly my best 25 yard group ever, one that could hang a pellet in the resulting hole:

[Atomic Powered Gruds]

With CO2 I wouldn't be to worried about the 12FPE mark just when I go HPA. Don't have much of a plan just want to have some fun and shoots some pests.

 These are some really good informative posts! I was thinking of also trying some "Coal Fenix FX 450 Pellets" and "Qiang Yuan Training Pellets" As I have heard some good things and personally have never tried a wad cutter and from what people are saying the heavier Coal Fenix FX should be better for weight and maybe size.

Jason you have so much information I am always ending up reading stuff you have wrote soaking up the information its crazy.

[aPpYe]

So it may take some time, but likely many of you will eventually reach the conclusion that MOST of your daily shooting would be better served by lower power, quieter, more shots per fill airguns.

I agree.  While I like tuning for full power, it is nice to have a power adjuster to back things off and plink all day at 20 yards or so with low power shots.  I usually like to shoot without a scope so perhaps that is why the differing zeros don't bother me all that much.  I still knock quarter-inch pebbles around easily enough.

[Ribbonstone]

Last couple of QB co2 I've played with haven't been geared towards power and weren't .177's.

Put one together a .22 out of spare parts (using up almost all the useful major spare parts besides screws, o-rings, etc.). 





(That one should have kept aPpYe happy enough...simple, no scope,a nice plinker.

Know the valve was "stock", but the transfer port was a "poly port" and I wasn't trying for power so the striker/striker spring at least started off as issued. Parts used were well smoothed/polished, as some of them were quite old and the early QB's tended to be a bit rough (the current ones much less so). Only .22 barrel not in use was already cut to carbine length (LDC and front sight added to bring it back to close to standard length).  Used an old QB78 standard stock (the ones they made before the 78 delux...but don't seem to be made now...and I kind of liked those old, thinner lighter stocks).

That one would run about 12 foot pounds in the warm months for about 40-45 shots before starting to fall off in speed.

So at least those minimal changes (maybe a little polishing of the striker/striker spring guide/ inside of the air tube where that striker runs back and forth..and a poly-port) would likely work just as well.

More recently, a non-standard QB on co2 was worked on for a bit. Put the barrled reciever of a 5mm HPA conversion onto the same co2 bottom shown above.  Only change (besides the caliber and barrel length) was a solid bolt probe (seemed an easier solution that modding a .177 hollow probe UP or modding a .22 hollow probe DOWN).  Smaller bore, energy about 11 foot pounds rather than 12 for the same 40ish shot count.

Worked on that one by way of a lighter striker and a little more spring tension, and kept fiddling around with combinations until I got +60 11 foot pound shots from two 12gr.

(Bonus was with the long barrel, long LDC, and a small gas use, it's impressively quiet.)

If I hadn't changed the striker weight (and I don't seem to have another one that's full weight in the parts box), I'd go ahead and put a .177 top on it and see how it does.  Expect something in the 9-10 foot pound range.

NOT saying that's all you can get for speed.  That's just all you get for the minimal changes made with a standard valve.  Are little changes, things that take no tooling other than hand tools, time, and a lot of cleaning up.  Besides, whatever you do to your QB, staring with smooth polished, lower friction parts and a more open transfer port won't hurt.

[Davo]

Last couple of QB co2 I've played with haven't been geared towards power and weren't .177's.

Put one together a .22 out of spare parts (using up almost all the useful major spare parts besides screws, o-rings, etc.). 





(That one should have kept aPpYe happy enough...simple, no scope,a nice plinker.

Know the valve was "stock", but the transfer port was a "poly port" and I wasn't trying for power so the striker/striker spring at least started off as issued. Parts used were well smoothed/polished, as some of them were quite old and the early QB's tended to be a bit rough (the current ones much less so). Only .22 barrel not in use was already cut to carbine length (LDC and front sight added to bring it back to close to standard length).  Used an old QB78 standard stock (the ones they made before the 78 delux...but don't seem to be made now...and I kind of liked those old, thinner lighter stocks).

That one would run about 12 foot pounds in the warm months for about 40-45 shots before starting to fall off in speed.

So at least those minimal changes (maybe a little polishing of the striker/striker spring guide/ inside of the air tube where that striker runs back and forth..and a poly-port) would likely work just as well.

More recently, a non-standard QB on co2 was worked on for a bit. Put the barrled reciever of a 5mm HPA conversion onto the same co2 bottom shown above.  Only change (besides the caliber and barrel length) was a solid bolt probe (seemed an easier solution that modding a .177 hollow probe UP or modding a .22 hollow probe DOWN).  Smaller bore, energy about 11 foot pounds rather than 12 for the same 40ish shot count.

Worked on that one by way of a lighter striker and a little more spring tension, and kept fiddling around with combinations until I got +60 11 foot pound shots from two 12gr.

(Bonus was with the long barrel, long LDC, and a small gas use, it's impressively quiet.)

If I hadn't changed the striker weight (and I don't seem to have another one that's full weight in the parts box), I'd go ahead and put a .177 top on it and see how it does.  Expect something in the 9-10 foot pound range.

NOT saying that's all you can get for speed.  That's just all you get for the minimal changes made with a standard valve.  Are little changes, things that take no tooling other than hand tools, time, and a lot of cleaning up.  Besides, whatever you do to your QB, staring with smooth polished, lower friction parts and a more open transfer port won't hurt.

I really like the look on your QB's, and how you have them tuned as well.

Did you notice any difference in accuracy with the target stock vs the standard?

Is that a 32mm objective on that scope?

Also, on your QB with the rear aperture sight, does it interfere with scope mounting?

[Ribbonstone]

Could mount a scope ahead of that little rear peep.

Had it in my parts box.  Came from an old Browning T-Bolt .22RF.  Dirt simple but no click adjustments, so it's like a game of ping-pong to get it sighted in.


No differnce in accuracy with the differnet stocks, although the heavier/fatter stocks will sit on a bench-bag better than the lighter/skinnier ones.  A little shorter in length, no rubber butt plate.  Actually, these onld "standard" stocked QB's had a metal plate inletted to the center of the hard plastic butt plate.


Yep, it's a 32mm 1" 3-9X Leapers....an inexpensive scope that has just refused to die over the years.  Co2 and PCP's are pretty kind to scopes, it's springers that tend to kill them quick.