Purgatory and Redemption
Tech Force TF-39 and Archer Airguns QB-78
As supplied by Compasseco.com and ArcherAirguns.com
Written By,
Eric Eikenberry
Writer / Contributor www.AirGunWeb.com

This is a story about one country which produces two different air rifles with two methods for propelling pellets down their bores. They’re similar in appearance though varying slightly with the individual nuances of function. One is amazingly poor at its job, the other just amazing!

Purgatory: The Tech Force TF-39
On the surface this little rifle looks like it should be a decent shooter. There’s a mild spring piston power plant which barely slings an RWS Hobby pellet (in .177 caliber) out at an average of 512 fps. There’s the all-metal and wood construction with a dark stain on the mystery hardwood and a flat black finish on the barrel and piston chamber/receiver. There’s an attractive aluminum muzzle brake on the end of the barrel and a rubber pad on the shoulder end of the stock. Ideally, this would be the rifle to hand to a pre-teen who’s ready to graduate from Daisy BB repeaters to diabolo-shaped pellets. The price is right, at just $50.96 for the rifle with a very basic 4 x 20 scope.

Unfortunately, that’s where the good points stop and the bad points begin.

First, the 4 x 20 scope is remarkably poor quality. Sure, it only costs $3.00 to add it on, and sure, the rifle doesn’t come with any open sights, but could they have at least supplied one where the image is in focus? I’d comment about the scope’s ability to zero in on a point of impact but I don’t want to get ahead of myself. There’s a well-machined scope rail on the chamber with a screwed-down scope stop. Take advantage of that fact and snag a good used Leapers 4 x 32 Bug Buster or a basic Centerpoint scope. I’d really like to see open sights included on this class of air rifle though, simply because, as a training tool, open sights are useful for kids. Leaving them off in lieu of a $3.00 scope with the optics of a child’s toy isn’t my idea of a good trade-off.

Back to the rifle; the trigger’s a bit heavy, but the pull on the single-sear is smooth. You can squeeze it the same way every time. My example had very little vibration, but a big, mean jolt which was far stronger than you’d expect from a 500 fps plinker. To say that this didn’t aid accuracy would be a huge understatement. Ordinarily, this is where I’d brag that, after much experimentation, and many rounds send downrange, I finally nailed the hold and achieved one-hole, 10-yard nirvana. It didn’t happen. Six different pellets, domes, wadcutters, points, hollow points, you name it, I tried it. Didn’t matter. This TF-39 spreads them out like a particularly slow shotgun. I looked closer and tightened the stock screws. That didn’t help. I replaced the marginal 4 x 20mm scope with a 3x9x40 AO Centerpoint sitting on Accushot mid-height mounts. Attempting to zero the rifle with the big, thoroughly-proven Centerpoint (this was used to devastatingly accurate effect in the TF-89 review) was useless.

I dug deeper. The muzzle brake was a little loose, so I tightened it. The break barrel hinge was loose, but the screw is locked in place with another set screw, eliminating any chance of adjustment. Worse, it’s a little wobbly when the breech is fully closed. Uh-oh. The leather seal at the breech was fully formed, but completely flat. It looks like it was installed, then sanded flat along with the metal which forms the breech, except for a fluffy “beard” which wraps around the bottom of the seal. It could be leaking pressure and, with a loose barrel, causing untold amount of accuracy issues. When I removed the muzzle brake I could see why the factory covered up that end of the barrel. There’s no crown to the muzzle at all. Where there should be a uniform rounded edge or precise bevel, there’s simply flat nothingness. The pellet skirt needs to exit without any inconsistencies at all. After looking at the details, I’m pretty certain with the issues this one exhibits, hitting the pellet trap at 10 yards is an accomplishment. At 15 or 20 yards, if I hit a soda can I’d earn my sainthood from the Pope for performing a miracle!

I’m going to go out on a limb here and say that there probably ARE TF-39 rifles which can shoot straight. All of the issues I noted could be corrected by a proper airgun smith… but who wants to take their plinker in immediately? I can’t recommend this particular Tech Force TF-39 at the moment.

Redemption: Archer Airguns -QB78
I have to be honest here, when Rick said he was sending me a CO2-powered QB-78 (the basic model) along with a pair of bipod legs and an Xisico 4 x 32mm scope, I was more excited about the legs and the scope! On the face of it, the appearance of the QB-78 doesn’t offer a plethora of pizzazz but you know what they say about a book and its cover, right?

In this case, the “cover” looks a little rough around the edges. The Shanghai Air Gun Factory apparently spends little time actually shaping and sanding the stock. The model I’m testing is the most basic package, which sells for just $74.94 but that’s no excuse for visible sanding scratches. It’s covered with a dark stain and appears to be solid. Sure, the 78 is a knock-off of the old Crosman 160 pellet rifle from the 60’s, but does the stock have to look like it was shipped through time. Modern quality control measures should be employed for the wood-working aspect too. Thankfully, there are several upgrade stock options from Archer Airguns, and more available at Richard’s Micro-Fit Gunstocks (www.rifle-stocks.com). The “target” stock from the AR-2078 model looks extremely useful. The pull length of the OEM stock is very short, more along the lines of a youth gun.

The metal work proves that the Chinese don’t believe in “polished steel”. The “bluing” is evenly applied over rough finished steel parts. A generous coating of lubricant, like Pellgunoil, is required in order for the bolt action to proceed with a minimum of fuss. There’s no “pellet seat” on the end of the bolt; it’s simply chopped off flat. Archer Airguns sells an oversize replacement bolt handle, which is probably a good choice due to the small size of the stock unit and the reluctance of the bolt to move. The front sight is a nice iron blade; the rear’s a flimsy piece of bent metal with two screws clamping it to the barrel and a folded stamped-steel stepped ramp for adjustment. As the 3x9x40mm Centerpoint scope wouldn’t clear the rear blade, I removed it. At 10 yards it would be fun for a kid, but at 20 or more yards, problematic with my eyesight. The barrel band looks like plastic, but it appears to be doing its job keeping everything in line. The crowning on the muzzle end looks acceptable at first glance. The trigger is a nicely-curved metal unit with a couple “steps” machined into each side, to increase finger grip. It’s not pretty, but it’s effective, even with the side-to-side play play. The release is nicely weighted and crisp.

Drawing on the original Crosman 160 design, this unit is CO2-powered with two 12 gram Powerlets. These are loaded with the pierced ends opposite one another, with one piercing pin deep inside the CO2 chamber, and the other built into the cap. When the cap is threaded onto the tube, it pierces one of the Powerlets. When the rifle is cocked and dry-fired the first time, it pierces the other. The evaporating liquid charges the assembly to 900 psi between 78 and 90 degrees Fahrenheit. Over 90 degrees though, the pressure will climb higher than what the hammer striker spring can release from the valve. There is no available degassing tool for this model; you have to shoot it empty. This is another clever upgrade from Archer Airguns.

Speaking of which, it seems Archer Airguns has an unending supply of modifications and parts kits available. Stephen Archer literally wrote the book (The QB-78 Family Workshop Manual) on the QB-78; the Chinese factory uses it as an instructional disassembly manual! Perhaps it’s only fitting that they have so much available for this little rifle. Make no mistake about it being little though (measuring just 39.5 inches from the muzzle to the hard plastic “shoulder pad”). Taken as a whole, it could easily be dismissed as just a “kids’ gun”.

Then you load it up with CO2 and shoot the first few pellets through it… and Baby Jesus smiles upon you! Rick shipped the 78 with a 4x32mm Xisico scope which he’d zeroed on the rifle. For shipping, he pulled it off and wrapped it in packing paper. I had to reinstall it after a cross-country journey via UPS. With no tweaks to the settings, and using pellets I’m sure Rick didn’t use to setup the scope, I had no problem placing one pellet on top of another on the 5-ring of the 25-foot bullseye “Qualification Target” I selected. Shooting from the bipod on my wood slab table, I was impressed. Perhaps even stunned. To back this up, the following day I loaded my last two CO2 powerlets, and started in with Crosman Premier Hollow-points. Same result. I switched to Crosman Copperhead Pointed hunting pellets. Same one-hole consistency. Mind you, it doesn’t shoot particularly hard. There’s virtually no recoil so you can see the pellet arch through the air on the way to the target. Shooting more than 5 pellets at a given target gets boring, as it stops making new holes unless you’ve fudged up somehow. I’m going to need far more CO2 very soon!

Run out to 20 yards, and the results were the same. Every pellet landed within 3/8ths of an inch in any given direction from the point of aim just as long as I didn’t make a mistake or twitch at the last moment. Most went right through the point of aim! The short pull length on this stock makes it uncomfortable for full-size humans to shoot for more time than it takes to carefully blast through one load of CO2. The AR2078 “target stock” and Archer’s “pull length extension kit” look like two reasonably-priced and extremely useful upgrades on my horizon! Did I mention the Xisico scope was very clear and bright with useful Mil-dot markings?

I’ll wrap this up by saying that Rick probably has some velocity numbers which would be meaningless without accuracy. When it’s shooting on a “normal temperature” day, the 78 is sort of magical, but I did note that first time, when the temperature was over 90 and the sun was directly on the rifle, the pressure rose high enough for the velocity to really drop off. Dreaded “valve lock” had reared its ugly head! The hammer spring truly wasn’t strong enough, just as it warned in the Owner’s Manual (yes, some people do actually read those things, myself included), to properly release the valve when the CO2 pressure goes over 900 PSI. Being that I live in the middle of the desert, I’m not sure there’s a good workaround for this other than to convert it to pre-charged air. I’ll be looking for a stronger, or adjustable, hammer spring setup soon, followed by a host of other ideas I’d like to try out.

There’s the real beauty of this design. It’s all metal and upgradeable. You can shoot one-hole groups right out of the box, or upgrade it a little into your personal idea of what the perfect little shooter should be. In today’s consumer-driven, planned-obsolescence world, it’s a refreshing throwback to the days when products were designed to be rebuilt occasionally. While the woodworking is of the sub-$50 category, the accuracy of the barrel earns its redemption in spades!

Written By,
Eric Eikenberry
Writer/Photographer
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