QB57 Breakdown & Lube Tune

[rebel415]

Hello, I have searched extensively but cannot find a simple step by step process for someone who has nothing but hand tools and has never taken an airgun apart. I did locate the professional tune by Gene SC and a thread from what I believe was the yellow chinese forum from 2006 where a 74 year old gentlemen had explained a little over my head but the pictures were no longer available. I found other threads where many on this board took them apart and tuned them themselves but not in depth instructions.

I have been into adult airguns for about 10 years now, but I just bought them, shot them, and if they needed a tune I sent them off to someone more capable. In the case of the QB57 I can't really justify spending more on a tune than the gun itself so I was going to try and do this myself. Just want to clean it up a bit, remove the rust, smooth it out,  and use whatever lubes are recommended in the appropriate places.

The little gun shoots very well and is pretty accurate however it is rough cocking and is dieseling a bit. I am not looking for more power although that would be fine, just trying to smooth it out a bit.

I did notice that the large allen head screw in the stock has to be taken out and then i assume one would take out the nut inside the pistol grip. Will this then allow the action to be taken out. I just didn't want the gun to come apart on me.  I seem to remember in 1 thread that there was a total of 3 screws or nuts that had to be removed to remove the action. I think the screw that holds the trigger guard on may be the 3rd one. Once I get the action out, how much more disassembly is required?

I don't want to mess with the trigger at all as it is fine and I have read that a novice doesn't want to mess with it nor the spring or anything like that since I don't have a spring compressor. I can probably purchase a cheap dremel if that would help or if I could do it by hand that would be even better.

Can someone point me to a thread that would help me or if not give me some basic advice on how not to injure myself in the process. I am looking for how to break it down just to the point that I need, what lubes to use and where to use them, etc., and any other good advice you can give me on this gun.

Thanks for any help you can give.
Sammy

[Magnum]

Hey Sammy, I saw some good  notes  in the library under "tune up guides for all airguns"  ( tuning the fast deer KL- B-3 is similar I think is to qb-57. Others may know for sure but still good reading I thought  http://www.gatewaytoairguns.com/library/Library_MainPage.htm   Hope that helps Tony.

[rebel415]

Magnum - 1/18/2010  9:52 PM

Hey Sammy, I saw some good  notes  in the library under "tune up guides for all airguns"  ( tuning the fast deer KL- B-3 is similar I think is to qb-57. Others may know for sure but still good reading I thought  http://www.gatewaytoairguns.com/library/Library_MainPage.htm   Hope that helps Tony.

Thanks a lot Magnum. A lot of good information in the library that I missed. I am going to start some extensive reading there now.

[mjb108]

I just took a QB57 apart and took a zillion digital pictures, one shot at each stage of the process.  Let me know if you have questions.  I don't know a terribly effective way to get the pix to you and I am in the middle of moving, so there may be some slight delays, but let me know.

btw, mine had never been fired but had numerous serious flaws including a leaky compression cylinder (I soldered it but haven't had a chance to go back and inspect the results closely) and  the worst burrs I've ever seen on the the breech.  (It was still fun, as always...)

Mike

[rebel415]

mjb108 - 1/19/2010  5:05 AM

I just took a QB57 apart and took a zillion digital pictures, one shot at each stage of the process.  Let me know if you have questions.  I don't know a terribly effective way to get the pix to you and I am in the middle of moving, so there may be some slight delays, but let me know.

btw, mine had never been fired but had numerous serious flaws including a leaky compression cylinder (I soldered it but haven't had a chance to go back and inspect the results closely) and  the worst burrs I've ever seen on the the breech.  (It was still fun, as always...)

Mike

That would be so helpful but I do know what stress it is to be moving so I am just grateful you had time to respond. I will send you a PM.

Thanks,
Sammy

[daveshoot]

I also did an amateur job on a pair of QB57s, and took lots of photos. I always do that, to help me get them back together ('specially trigger assemblies)! I was pretty happy with the results.

The QB57 is small enough that you can try something I don't like to do with bigger springs: use a woodworking clamp as a compressor. Before I built a compressor, I used the black pipe style clamps to compress the spring. These are actually a little scary because there isn't much purchase area, but I was pretty careful and used some wood blocks to prevent slippage and metal on metal contact.

I have done some bigger rifles since, and now I see why we build compressors. I follow the same rule with the compression that I do with the gun: don't point it at anything you don't mind shooting (i.e., yourself).

The 57 is a pretty easy gun to start on. I had one picture of the disassembled piston assembly on my GTA album... here it is... lots more at homeif you get stuck.

Oh, also if you can "spring" for the QF-2 seal and spring kit ahead of time (they were like 8 bucks) you can use them in your tune. Someone said that spring was a little more powerful than the stock 57 spring, and you get a nice new seal. I didn't do this so if anyone did, they can chime in, but I seem to have heard it from a reputable source.

[vme]

I just recently bought a QB57 and I'm quite happy with it.  But I was trying to add a new scope and can't get it to group consistently.  Is it possible that the handguard moves on the barrel?  Has anybody removed the handguard?  Has anybody removed the barrel shroud with the front sight and managed to get it back on, without destroying it?

[daveshoot]

The handguard can definitely move, and so does the whole front half of the rifle. The lock down nut is hit and miss, because there is a keyway with a mating pin that is supposed to lock them together. They are not usually a very exact fit, and the slop allows the barrel to rotate in the receiver. On mine, I pretty much abandoned the take-down aspect and I lock that knurled thread down with a rag and channel locks.

I haven't removed the handguard but others here have done it, so it is possible.

[vme]

Thanks for the fast answer, Dave.  I'm reluctant to abandon the takedown feature, but it certainly is a last and definte solution.

[daveshoot]

You could check the fit and if it is loose, build up the slot to match with some metal. I am just not that good with metal work of that nature. It would really be nice if they mated up exactly to restore the James Bond utility.

I did a lube tune and it responded very well to that. Honing out the cylinder and lubing made it remarkably consistent. I was getting 550 fps in .22 with an SD of 4 something afterward, and I was pretty happy with that. It has a good barrel and shoots well.

The remote trigger also came around with some polish. You wouldn't mistake it for a Rekord but it turned out better than my B3s.

[ezman604]

First of all Victor, welcome to GTA forums. Glad you found us and joined all us airgun addicts!!!

The handguard has 2 allen screws holding it in place. It's quite possible they are loose. The factory scope mount isn't the best either. Justthree small wood screws holding it in place? I could not get a set of standard 11mm scope rings to clamp down tight enough so I added a Hawke adjustablemount to mine. Then just clamped the scope down onto that. Very solid and this gun, although not powerful, will punch extremely accurate holes at 25 yards with .22 CPHP rounds. Check this post out here[/b][/i] and see my rework project and results. And the barrel nut CAN cause a problem. I contacted Stephen Archer and asked about the proper way to adjust this thing and he said the best way he has found was to hand tighten it, release the cocking lever and pull back just slightly and tighten the barrel nut again. This will make for a tight fit and good seal between the barrel and compression tube. These are extremely FUN shooters!!!!

Again welcome....and Happy Shooting!!!!

Dave

[Stephen Archer]

Yes, the somewhat "hit and miss" nature of the front and rear parts of the rifle is a manufacturing issue. I talked to the VP of Design and Manufacturing at the Shanghai Factory when I was there last September. They understand the problem, but fixing it is more difficult for them to achieve. So, I try to match front and rear parts of the QB57s we sell to minimize the issue for our customers.

The front end of the QB57 can be completely dis-assembled quite simply. The plastic front sight assembly is a tight press fit. It can be removed by first heating with a domestic hair dryer (not a heat gun), I then place a piece of wood against the rear of the assembly and knock it off with a sharp blow from a rubber mallet. Re-installation can be done with the part "cold", I just tap it into place again with the rubber mallet. The screws underneath the wood handguard can be removed and the handguard simply slid forward off of the barrel once the front sight assembly has been removed.

As others have said, these are a fun gun and can be very accurate, but they certainly benefit from a little "love" from their owner.

Stephen Archer
Archer Airguns Inc.
Store: http://www.archerairguns.com
Blog: http://www.archerairguns.info
Video: http://youtube.com/archerairguns

[vme]

Dave ezman604, Stephen Archer, Daveshoot, thanks for the welcome and the excelent tips!  Dave ezman604, you really did an amazing job on that QB57.  If I were your grandson, I wouldn't want to go back home
I guess I'll try to emulate your "bull barrel" - moderator.  Till now, I only changed the attachment of the trigger return spring (to make it lighter), then I added a sort of thick washer to the pin that engages the sear to shorten the trigger pull and lenghtened the trigger as it was a tad short and my finger tended to slip down on it and rest between the trigger and the trigger guard.
When I tried the QB57 with the included 4x20 scope, I shot a nice group with Crosman pointed (.22) at about 20 yards.  Then I tried to install a Leapers 4-16 x 50 and it slipped on the rail due to the dimensions issue Dave mentions in his project.  I have cheap Tasco rings so I just filed them down so they would adjust and put two 3/16" screws in the rail to stop the rings from moving.  Guess there is still something moving :0
On the weekend I'll try to do some more shooting and investigation.
By the way, I shot just two Crosman pointed pellets over a friends chrony and it was just over 600 fps.

[ezman604]

Thanks for the kudos Victor. It's fairly easy and cheap to make a barrel shroudsimilar to mine.

And Sammy, sorry. The welcome was meant especially for you since this started out as your thread. I wasn't paying attention. Old age??? HeeHee

Anyway, welcome to both of you. The information is there for anyone interested in the QB-57 tuning and modding. It's a sweet little gun. And Victor, that's some good numbers out of yours. I added the QF2 kit of parts, honed the cylinder and lubed everything with moly and was still only able to get 500fps out ofmine with 14.3gr CPHP. It's EXTREMELY accurate but punching paper at 25 yards, the lead tends to ricochet back instead of penetrating my backstop. We will just have to be careful and wear protective eyewear when shooting. Hope to let him have his first look at it this weekend. I'll post pictures.

Stephen, thanks for your support of thehobby of airgunning and for excellent customer service!!!!

Dave

[vme]

Dave, I think you mentioned the possibility of installing a Gamo spring in the QB57.  A guy in an argentine forum (http://foro.cazaconaire.com.ar/index.php) installed a Gamo Hunter 440 spring and said it was a direct swap giving better energy.