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31 May, 2009

Testing, Testing and Improving...

Here's one from the archives.

Carefully packed among some product we received from the Shanghai factory a while back was this "Certificate of Inspection" with attached test target - obviously from the QA Department.

It's notable for several things...
1. It gives a specification for the accuracy testing - 3 shots at 10 metres with a maximum CTC of 8mm. The test target shows a CTC of 6mm. A pretty good group.
2. It's a test target for an AR2078B or AR2079B - the very rare versions of the AR2078A and AR2079A that are cocked by a slide lever mechanism, rather than a bolt. Very few of these guns have ever made it to the US and I've only handled them myself at the SHOT Show. And "B" models were not among the products we received in the shipment.
3. The serial number on the test target - 08682567 - does not match the serial number on the Certificate of Inspection it's attached to - 08682566. Oops!
4. It shows the characteristics of the gun that the factory tests for quality, bore diameter, accuracy, trigger pull weight, overall weight (this varies quite considerably between individual units due to differences in the wood used), functionality of the rear peep sight, performance (probably overall operation), and finish. It also gives a grading system "Result" to the inspected product.

There's no question that output quality from the Shanghai Air Gun factory is improving all the time and this document gives us a small view into the efforts they're making.

But, it also shows why Archer Airguns recommends "Gold Service' testing. Here we have evidence of a functioning QA system, but with some unfortunate lapses - the wrong test target on the Certificate of Inspection, and the document included with a completely different batch of guns as if someone knew they had made an error and didn't know quite what to do about it...

But don't laugh too loud, they're getting better all the time - and anyway, who's perfect?


26 May, 2009

Lead free Pellets - Are They Any Good?

Great claims are made for lead-free pellets. Crosman claims their lead-free pellets have ultra-high velocity. Gamo says that their Raptor Power Pellets increase the power and velocity of your airgun up to 25%. But do they?

In this post we’ll see what happened when I tested four pellets through the same air rifle.

The air rifle used was a factory-spec QB78 in .177 caliber - the first one I pulled from the rack. I gassed-up the gun, sighted it in with a red dot scope and then shot four strings of 5 shots each from a rest in one session at 64 degrees F to ensure consistency, with the following types of pellets:
- “The Peak” lead wadcutters with an average weight of 8.65 Grains
- Crosman Premier Light lead domes weighing 7.96 Grains on average
- Gamo “Raptor Power Pellets” lead free, pointed and weighing 5.04 Grains on average
- Crosman “Silver Eagle” lead free wadcutters, average weight 4.40 Grains

I didn’t select the gun or the pellets. All were shot “just as they were” to make a real world comparison.

The results? Well sadly, the lead free pellets don’t perform well at all.

Compared to the slowest lead pellets - The Peak wadcutters - the Gamo Raptors were a pathetic 6% faster - in spite of the claims of “25% increased velocity” emblazoned on the packaging. Another claim on the Gamo packaging is that “If your gun shoots 600fps, velocity will increase up to 750fps. Nope, not with this gun, they don’t. Crosman is less extravagant in its claims, but the Crosman Silver Eagle wadcutters did improve muzzle velocity by 16%

Also note that the slowest pellets - The Peak wadcutters - actually had the greatest muzzle energy, while the Gamo Raptors (which again claim to increase the power of your airgun by up to 25%) actually generated 35% LESS muzzle energy than those slow old lead wadcutters. Hunters require muzzle energy for a clean kill, lead free pellets obviously don’t deliver.

Gamo also claims their “Performance Ballistic Alloy” improves accuracy by 25%. Not true, I’d say, based on the results of this test. Accuracy of the lead free pellets was between 2 and 3 times worse than the lead pellets.

As you can see, the Crosman Premier Light lead pellets were very accurate in this gun - a great choice. I use The Peak lead wadcutters for Archer Airguns “Gold Service” testing and have good luck with them: again we have an excellent group, but with one flyer half an inch from the main group. The Crosman lead free wadcutters made a ragged open group. As for the Gamo pellets - well we can see only four holes, so two pellets must have gone in exactly the same place, but then we have a flyer a full 1 1/2-inches away from the group. The lead free pellets tend to shoot to the right of the lead pellets.

Here’s the numbers, the test targets are below:
The Peak wadcutters 8.65 Grains weight, 577.7 fps muzzle velocity, 6.4 ft/lbs muzzle energy
Crosman Premier Light domes 7.96 Grains weight, 598.8 fps muzzle velocity, 6.3 ft/lbs muzzle energy
Gamo Raptor lead free pointed, 5.04 Grains weight, 614.2 fps muzzle velocity, 4.2 ft/lbs muzzle energy
Crosman Silver Eagle lead free, 4.40 Grains weight, 670.5 fps muzzle velocity, 4.4 ft/lbs muzzle energy

For those who must have the highest muzzle velocity, the Crosman Silver Eagle wadcutters increase the performance of this QB78 by nearly 100 fps. But is it worth the compromise?

Take a look at the test targets. What do you think?


19 May, 2009

How accurate is the QB36-1 and who makes it?

Here’s an interesting couple of questions that we were asked the other day. As the QB36-1 is a relatively unknown air rifle, the answers may be of interest to you, too.

The QB36-1 is a mid-powered underlever-cocking springer. It’s a solid gun with very few plastic parts and a wood stock that’s pleasant to shoot. You can read more about it on our web site.

In our Gold Service testing for the QB36-1, I’m producing test targets in the 0.7-inch to 0.75-inch CTC range for 10 shots at 10 yards off open sights or a 1x red dot sight with “The Peak” wadcutter pellets.

So how does this compare to the QB78? Well, my average QB78 groups are in the 0.5 to 0.6-inch CTC range under the same circumstances, but I’m really NOT a good springer shot and I believe that the inherent accuracy of the gun is better than I can shoot it. And, of course, fitting a scope will help, too. So, I would say that the QB36-1 is an accurate air rifle for the price with QB78-level accuracy - which is a good recommendation in most people’s books.

Our testing shows muzzle velocities close to the manufacturer’s claims of 700fps in .177 cal, too.

And the manufacturer? Well, it’s our friends the Shanghai Airgun Factory - the manufacturers of the much better-known QB78 family. The QB36-1 is an Industry Brand product and you can see it on the factory website.


14 May, 2009

Do You Need The Pellgun Oil Treatment?

Sometimes we're contacted by folk whose QB78 family air rifle "leaks a bit" and they ask me what to do. The answer is that, before you tear the air rifle apart and install new seals or a new valve, try "The Pellgun Oil treatment".

Here's how...

Take a 12g CO2 Powerlet and add one good drop of Crosman Pellgun Oil to the flat tip, facing into the gun. You can use a pre-used Powerlet as the second one, facing out towards the front of the gun. Tighten the Tube Cap as usual and "dry fire" the gun with no pellets until the CO2 from that one Powerlet is exhausted. Then stand your gun in a corner and leave it for 24 hours. Load new Powerlets and test fire.

Miraculously, the leak will often have disappeared!

So what happened? Well, the Pellgun Oil has been blown through the gun and coated all of the seals and O rings. The oil causes dry O rings and seals to swell just a little and this can often "re-seal" your gun and eliminate the leak.

If this doesn't work, don't despair, just repeat the treatment. Sometimes I've found that a couple of attempts are necessary for success.

Archer Airguns sells Pellgun Oil on our Accessories page at

But if this fails, then you will probably need either one of our Seal or Valve Kits - together with maybe a copy of my 88-page "QB78 Family Workshop Manual". Plan to spend some "quality time" bringing your QB78 back to health. But at least you tried the easy way first...

Oh yes, this trick also works for the Crosman 160, 167, 180 and similar CO2 air rifles. If you have one of these old guns and it's not been fired for years, the "Pellgun Oil treatment" could be all that's required to have it shooting again like new!


07 May, 2009

Where Do I Buy Duct Seal For Your Silent Pellet Traps?

We're asked this question very often!

And yes, everyone knows that you can buy it from Archer Airguns, but it's expensive because of the shipping. We recommend that you purchase this locally from Home Depot, Lowe's or one of the other "big box" DIY centers. But you have to know where to look.

Duct Seal is found in the electrical section, usually tucked out of the way somewhere. You may need to ask for it. You're looking for one pound lumps of the stuff, it's a dark gray color (maybe shrink wrapped onto brown card), not an attractive-looking product - but it's ideal for use in our pellet traps. We've tested and recommend "GB" (Gardner Bender) and Halex brands of Duct Seal - that's what we ship and they work fine. Both brands are pictured above.

Oh, and please remember, our "Silent" Pellet Traps are designed to be used with Duct Seal - not plumber's putty or any other kind of putty. We've had some customers try different types of putty because it's easier to find or cheaper, but they've always been disappointed with the results.


05 May, 2009

Here's How Crosman Manufactures Powerlets

It's a very interesting and professionally made video, obviously filmed at the Crosman plant. Certainly worth watching while it stays on YouTube. Click on the title above to view the video.

And that certainly sounds like a British accent doing the "voice over" but it's not me...


02 May, 2009

How Many Shots Can I Get From a QB79?

We’re often asked “How many shots can I get from one CO2 tank with a QB79?”

OK, so here’s the scoop...

The QB79 can be used with 3.5-ounce and 9-ounce re-fillable paintball tanks. Or a Daisy Avanti re-fillable tank. These are all mounted directly onto the gun. Alternatively it can be used with Crosman AirSource 88g tanks, in this case a Crosman AirSource/Paintball Adapter is required.

Our photograph compares a 9-ounce paintball tank to the Avanti tank, an AirSource tank with adapter and 12g Powerlets, as used on the QB78 model.

The number of “good” shots per tank are:

2.5-ounce Daisy Avanti tank about 150 re-fillable
88g AirSource tank (adapter required) about 220 single use
3.5-ounce paintball tank about 240 re-fillable
9-ounce paintball tank about 630 re-fillable

By comparison, a QB78 with two 12g Powerlets provides about 50 “good” shots before the point of impact starts to fall significantly.

As with many other things in life, “your mileage may vary”. But these figures are a good approximation.


Three Tips for Using the QB57

Here’s one “do” and two “do nots” when using the QB57.

First, the “do”.

After you’ve been shooting the gun, it can be very difficult to unscrew the barrel locking ring to take down the rifle. The ring locks tight. To overcome this issue, pull out the cocking lever a little - not a lot and certainly not enough to start cocking the gun - and then unscrew the locking ring. Now it’s easy to turn and you will be able to separate the two parts of the gun.

Now the “do nots”.

First. When cocking the gun, do not hold it by the pistol grip. If you do, the pistol grip can snap right off and you’ll need to purchase a new QB57 Stock Kit from Archer Airguns! Instead, hold the gun by the wood fore stock around the barrel.

Second. Do not hold the gun tightly when shooting. Hold the pistol grip lightly to keep the gun on target and pulled into your shoulder. And don’t grasp the forend tightly when shooting. Simply rest the fore stock on the open palm of your hand. Shooting the gun in this way will improve your accuracy considerably!


New Tube Cap for the QB78 Family

There’s a recent and unexpected design change that’s been made to QB78 family air rifles with serial number starting at around 08686XXX.

This change comprises a new design of tube cap and a longer main CO2 tube.

The tube cap itself is about 1/2-inch longer than the previous version used on all earlier guns - as you can see from the photograph. Because of this, the main tube on these guns is correspondingly 1/2-inch longer. Although the threads are interchangeable, the caps themselves will not work properly if used on the “other” model of main tube.

The new design certainly makes it easier to change a defective tube cap O ring, but - apart from that - it’s not so easy to see the benefit of the change.

Removing the new tube caps is quite difficult when new - the tube cap needs to be pulled hard and wiggled a little - although this becomes easier with some use. And the cap benefits from being pushed square down onto the main tube when fitting.

The Tube Caps available from Archer Airguns are all the old pattern.

So is the new tube cap an improvement? The jury is still out on this question...


About This Blog

This blog shares information, ideas and knowledge about air rifles. It compliments the information Stephen publishes on the Archer Airguns website, on YouTube and the Chinese Airgun Forum.

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