GTA
General Discussion To Gateway To Airguns => China Gate => : hdrider April 16, 2009, 12:33:33 PM
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How do I identify a QB36-1 model from a QB36-2 model and what are the specs on the respective rifles?
I've got an underlever .177 caliber airgun perchased a few years ago at a gunshow. It's identifying marks are:
Shanghai China
QB36
M530597
What exactly do I have here and what accuracy could I expect without modifications?
Also, I notice it has short (4" long} scope mount grooves, but no scope stop. Do I need a scope stop for this gun, and if so could I drill or dimple the top of the airchamber (or?).
Thanks,
Dennis
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hdrider
Welcome to the site. The -1 in my opinion is a smaller lowered powered less expensive -2. Take a look at Compasseco web site. The -1 is there TF 97 and the -2 is the TF 99. Also take a look at Archer Air Guns web site. The prices on these vary a lot so shop around. I have the -1 and it is a fun gun. I got a Leapers 6X32AO Bug Buster and a compact one piece mount on mine. That combo fits on the short rail and gives good clearance for the loading port. I have been shooting peak pellets in mine and quarter sized groups at thirty feet are easy to achieve so for the money it's not too bad.
W
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Walt,
Looks like I've got the QB36-1.
You didn't mention anything about scope creep -- do you use a stop pin with your scope or doesn't this lower power rifle need one?
Also, concerning the pellet choice, I wasn't familiar with Peak Pellets -- checking the internet it looks like they are a cheaper version of Crossman Premiers. Have you tried the Crossman Premiers in your gun? How do they compare with the Peaks. I have both the Crossman Premier Hollow Points and Lights available. If I can get the accuracy you're seeing I'll be happy.
This gun has been in storage a couple of years -- is there anything I can do to myself to "revitalize" or replace the Air Chamber seals?
Dennis
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No scope creep. can't remember if there was a hole in the top of the compression tube I took advantage of or not. What I did do for sure was clean up the groves with isopropyl alcohol and same thing for the clamp area on the scope mount and applied a small amount of blue Lock Tight in the groves just before clamping on the scope mount. Let it dry over night. Peak pellets are a inexpensive pellet available from Archer Air Guns. In my lower powered air rifles IMO I find they are quite accurate and the price is reasonable. I have used the Crosman pellets from WalMart and they are good too. If you take your gun down and it has the leather seal I think you can revitalize it by roughing up the sides a little with a course sand paper and soakings it in a blend of Neatsfoot oil and silicon oil. I got the Neatsfoot oil at the shoe repair shop and the silicon oil at my local R/C shop While it's apart it's a good time to lube the rest of the gun. I put in a link to the pellets and another link to loads of good info.
W
http://www.archerairguns.com/airgun-pellets-s/5.htm
http://www.airguntoys.com/tuna.htm
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Walt,
I put a GAMO scope on the old QB36-1 and tried to sight it in last night with Crossman Premier Light Pellets. I had really forgotten how utterly terrible this gun was -- the best I could do was about 6" or larger groups at 15 yards which makes this gun pretty useless. For comparison I bought a new GAMO Big Cat at Wallmart last week and it shoots 3/4" or better groups at the same distance (I put the Big Cat Scope on the QB). In shooting the QB I noticed that the Crossman Pellets seem to fit more loosely in the QB than in the Big Cat -- I may have one of the infamous oversized Chinese barrels that I've occasionally read about in the message groups. Is there any hope for my QB or do I just toss it back in the closet? I was originally thinking of fixing it up and giving it to a starting novice airgunner friend, but I wouldn't wish a gun this inaccurate on anyone.
Dennis
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The gun should do better than that. The good ones are pretty accurate.
Are you sure it isn't the scope/mount? Was performance the same with iron sights?
Check the crown for burrs.
If you have a chrony, check velocities for consistency- could be a shot seal.
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The gun shot just as bad with the open sights and didn't improve (or get worse) with the scope.
Unfortunately I don't have a Chrono to check velocities -- which seal might you suspect -- the transfer port seal or the spring piston seal? This gun never shot accurately so whatever was/is wrong came that way as new.
How exactly do I check the crown for burrs -- can this be done visually or do I need to run a pellet down the bore?
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hey welcome to the forums :) . yes you can do it visualy . use a magnifingy glass you should be able to see any defects .if you just need to clean a few burs plug the barrel with a qtip and use a brass screw in a drill with some vavle lapign compound go slow and a level as you can get . that should polish it up nicely .
have you cleaned out the barrel ? if not do so with a pull though(yo can make one with some weed wacker line) with a couple patches with some goo gone then dry patches until clean . if the pellets you have dont fit in the bore well you could try soem diffrent brand pellets . i have found the some pellets fit some bores better than others .
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I looked at the barrel crown -- didn't see much there but cleaned it up by hand using a rounded/tapered grinding stone. I also cleaned the bore and tried 5 different pellet types. The Crossman Premier Lights and The Crossman Premier Hollow Points were both the most accurate, but the the grouping was still large at 15 yards -- about 1" wide x 3" long (5 shot groups). When I tried Daisy Precision Max Pellets it made an almost vertical line 5" long but very tight horizontally (5 shot group). It's like I'm getting some huge variations in velocity.
What would be the most likely suspect for this -- broken spring, piston seal, transfer seal, pellet variation?
Also, where would I get replacement parts for this gun?
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sounds like a bad seal if it is striging them verticaly like that . i am not to sure about the parts for that particular rifle i will look around i see if i can locate a parts source .
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i jsut thought of something , how old is your gun ? are the seals leather ? if they are they may just need some lube .
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The gun is at least 5 or 6 years old, but it never did shoot right. The seals are probably leather as you described. I read online about putting WD40 in the chamber to soak the seals and to follow up with Slick 50 advanced formula -- sounds kind of drastic so haven't tried it. What do you suggest to check/lube seaks -- disassembly?
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first i would try this
Charlie’s Chamber Lube……
Mix 1 part NeatsFoot oil to 3 parts 100% Silicone Shock oil. . Example: 1 ounce of NeatsFoot oil and 3 ounces of Silicone Oil. Also, ¼ ounce of Teflon can be added if you have it. That will be enough to last for years if used just as a chamber lube. Used for guns having a leather seal.
if that dose not work you may need to fabircate a set of leather seals .
http://www.gatewaytoairguns.com/library/Making%20Leather%20Seals.htm
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I got some Neatsfoot oil at the local tractor Supply, picked up some Silicone Brake Fluid (DOT 5) at the local auto parts store (couldn't readily find Silicone Shock oil), and have some Slick 50 Advanced Formula which contains teflon. Would these work OK for mixing up a batch of "Charlies Chamber Lube". Also, could you tell me how your supposed to use it? That is do I remove the piston seal and soak it overnight in the Lube, then reinstall the seal?
And finally, do you periodically drop some in the chamber -- if so, how often and how much?
By the way, I decided to go ahead and order a Shooters Chrony to document the before and after muzzle velocities and spread before I tear into it. Seems like a useful instrument to trouble shoot the health of the ailing Q36 as well as my almost new (and apparently healthy) GAMO Black Cat. Concerning the use of the Chrony, do you normally shoot 10 shot groups to get a good idea of FPS variations?
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not sure about the chrony , i have yet to buy one but 10 shots sounds about right . i think the silicone shock oil is for radio controled cars . as long as what you got is 100% silicone it would work fine . i dont think you would need the slick 50 . i would take it apart if yoru are able to do so and i think you soak the seal in a cap (like from a 2 liter pop cap)half full of wd40 for a few minitues then soak it the chamber oil you mix up for at least a few hours. if the leather seal is slick and had you can rough it up with a bit of sandpaper , but not to much . keep me uptated i did that to my old dasiy 250 break barrel and it really shot alot better . if you need more info check the library link on the top of the page , a lot of very useful info there .
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I got my Chrony today and did a test of 20 shots from the QB36 using Crossman Premier Lights. I think the results pretty well tell the tale of a bad piston seal. The first 3 shots were 525.3, 536.8, 468.7 after that everything was in the 300's. The low was 302.6, High 536.8, Avg 370.3, Extreme Spread was 234.1, and Standard Deviation was 64.86. From what I understand you want the Extreme Spread to be 30fps or less -- mine's 234!
I did the same 20 shot test on my almost new GAMO Big Cat and got Low 894.7, High 931.5, Avg 913.3, Extreme Spread 36.05, Standard Deviation 10.00 -- almost good results, but the spread of 36 indicates I may have some work to do on it also.
Also, I bought a Tech Force 97 "cleaning kit" from Compasseco -- it came with new seals and a new spring. Unfortunately it came with a new leather seal instead of a synthetic one and it's literally hard as a rock. Guess I'll need to soak it in Charlies Special Lube mixture to soften it up before installation -- any advice on that would be appreciated.
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hd -
Was there anything else included in the kit besides the seals and spring (e.g. trigger parts)? The picture on the Compasseco site looks like a kit for a B3, instead of a TF-97/QB-36. False advertising to show synthetic seals and then send you a leather one. Also, is there any difference between the stock spring and the one in the kit?
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The packing slip said Tech Force 97 cleaning kit, hoewver the actual "Shooters Choice" box was marked QF-2 and B2 whatever that means. I received the kit very quickly (within a couple of days)
Besides the cleaning stuff the following parts are included:
Spring -- approx 18mm OD x 12mm ID x 267mm Long -- I haven't compared this to the existing spring yet
Trigger Part (1) -- looks like the part that catches the piston when cocked
Trigger Spring (1)
Leather Washers (3) -- approx 12mm OD x 6mm ID -- not sure what those are for yet
Synthetic seals (2) -- approx 12 mm OD x 7mm Long -- cylindrical outside with a conical hollow interior 10mm ID to 6mm ID
Leather Piston Seal consisting of a Leather Cup (1) with a synthetic interior plug (1) with a phillips head screw (1) through the center
I'm just about ready to pull the QB36-1 apart to see what these parts correspond to and if they are the correct size for this gun and what condition the existing parts are in.
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My friend fixed his seal problems using this kit, pic in link.
http://i363.photobucket.com/albums/oo80/willis61/Air-Rifle-Cleaning-Kit.jpg
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The Pic "looks" like the same kit I have, but I can't tell from the photo what the part number is on the box. Could you ask your friend what numbers were stamped on the side of the box? Did he also have a QB36-1 or TF97?
Also, I just now disassembled the QB36-1 and checked the spring lengths. The Spring in my gun is about 1.25 inches longer than the spring I received in the kit. The Kit spring is 34 coils long while the stock spring is 39 coils long. I don't know if the shorter spring is an "upgrade new design" or just a spring meant for a different gun. The spring will fit fine, but just have less precompression (which may be good??). Not sure right now whether I should reuse the stock spring (which has a slight bend in it from being in the gun I suppose) or stick the shorter spring in and see what happens.
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It seems strange, but it is labeled as Industry Brand QF-2, which is what you have, si I can't understand why you should have a leather seal in yours. As for the mainspring, I can't tell you as he used a spring called the "Titan XS" mainspring. His rifle is a QB36-2.
ATB, Graham.
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hd -
That QF-2 cleaning kit is intended for the B3 and B4 models by Industry brand. Here's a link to a similar kit at South Summit:
http://southsummit.com/catalog/product_info.php?products_id=629
I haven't taken my TF apart yet, but from what I've seen and read, the trigger parts will not fit your rifle. The breech seal will likely work, as will the piston seal, provided you can come up with a way to mount it. Most B3 models have leather seals like the QB and TF, and need an aftermarket "button" to mount the synthetic seal; the B4 came from the factory with a synthetic type, so the swap is much easier.
Good luck with the rebuild. I'm looking forward to hearing how it turns out.
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The QF-2 kit I received from Compasseco (which they claim is for a TF-97) looks the same as that pictured on the South Summit website, although the description of what's included looks pretty cryptic.
I compared the parts in the kit to those I removed from my QB36-1 yesterday and confirmed that the trigger parts (Spring and Release Pawl) are identical. The leather piston seal and breach seals are also a direct replacement for the existing leather piston seal and breach seal. My existing leather seal was dry and pretty "carboned" up
Two things that still puzzle me about the kit are the shorter spring and the 3 leather washers that were included. I think I'll install the shorter spring and see what happens (using the Chrony), but I still have no idea where the leather washers are supposed to go. Does anyone have any idea where leather washers are used in a QB36-1 or TF97?
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hd -
Glad to hear the parts fit - I was obviously wrong about the contents of the kit. I guess you can't always trust a picture in a catalog.
Sorry, I can't help with the question on the leather washers - I've yet to tear into mine to offer any suggestions. But, I'm sure there are others here that can lend some advice.
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hd -
I found the exploded diagram for the QB/TF, as well as the parts list, and have attached scans of both. I don't see anything that could be a leather seal, as you received in the kit. But then again, this list is not comprehensive - I also don't see a breech seal listed, but obviously the rifle has one.
Hope this helps.
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Thanks for the parts listing. I noticed that there are several parts shown that aren't on my QB36-1 -- perhaps I've got an early model? Mine is missing parts # 26, 27, 29, 32, and 33. It looks like those parts are all related to safety locks that may have been added in a later design version.
I also took another look at the Piston Spring to figure out why the new spring was shorter (34 coils versus 39 coils that was in the gun). The new spring is made out of slightly larger wire (.120" dia versus .117" dia) and has a slightly smaller coil ID -- looks like the new spring is shorter but stiffer so hopefully will provide the same/better results.
I should have it back together in a couple of days and then Chrony the results and check accuracy, and then post them here.
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I checked some on-line coil spring calculators and found that the .003" difference in wire size equates to about 40 pounds/inch difference in compression force. So -- it looks like the newer, shorter spring supplied with the QF-2 cleaning kit from Compasseco is actually equal to or stronger than the original spring. I'll know for sure once I get the gun back together and get a chance to Chrony it.
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Not sure about parts #26, 27, and 29, as I haven't yet disassembled the trigger. Parts #32 and 33 are, as you stated, related to a safety mechanism that hooks into the cocking mechanism. You have to depress the tab on part #33 to return the cocking arm to its locked position prior to firing.
Look forward to seeing the chrony and accuracy results from the kit spring.