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13 August, 2009

QB57 Performance Review. Part 2 - Accuracy and trigger Pull


This is my own cutomised QB78, with a re-finished and extended stock, muzzle brake and other modifications.

Here’s some more, never previously published, “hard data” on the performance of the QB57 air rifle from Shanghai Airguns. It’s derived directly from Archer Airguns “Gold Service” testing of these guns and summarises results from a large number of tested guns.

Part 1 covered muzzle velocity testing. In this second part we’ll cover accuracy and trigger pull results.

The factory spec for accuracy is a grouping of 30mm - that’s 1.2 inches - CTC (center to center) at 10m (32 feet) for just 3 shots. This spec is not impressive (in fact it’s terrible), but performance is hugely better in practice. In “Gold Service” testing, we see an average CTC of around 0.6 inches for 10 shots at 10 yards - 2X better than the factory spec - as this chart shows.

This compares very well with the tested accuracy of QB78 family air rifles - it’s about the same CTC as “Gold Service” testing produces with these accurate CO2 guns. And I’m emphatically NOT a good shot with a springer, I just can’t manage a completely consistent hold time-after-time, so good spring rifle shots using pellets the gun “likes” will undoubtedly be able to improve on my accuracy results.

Average accuracy is slightly better for .177s over .22s (just as with the QB78 family), but there’s actually very little in it. It’s too close to call without an even larger population of guns to test. Just give me more time, I’m working on it...

Most of these accuracy results are obtained using a basic Leapers red/green dot scope. Where customers specify our QB57/Leapers Scope Combo, the test results were achieved with that combination. I’ve not differentiated between sighting options in this graph, but you can understand that most of the “tight” groups were sighted with the 4 x 40 scope.

As I measure CTC only to the nearest 1/8-inch, that accounts for the steps in the graph. But, as you can see, here we have an accurate little air rifle!

The QB57 has a long, creepy trigger pull - as you might expect from a cheap bullpup-style air rifle. But it’s actually not that bad and is surprisingly light and consistent. There’s also an adjustment screw, but I never touch that so this data represents completely “stock” trigger performance.

The factory spec provides a very generous range from a maximum pull weight of 5 lbs 10 oz (itself not unusual in a cheap spring-powered air rifle) down to a minimum of 2 lbs 4 oz. But the actual results are much better and are shown in this chart.

The good news is that trigger pull weights are all very close to the minimum factory spec and - as you can see - a reasonable average figure is around 3.0 lbs. Again, a very good performance for such a low cost air rifle. And the trigger is adjustable via a setscrew, so there’s the potential to improve these pull weights beyond the stock factory settings.

So, that’s the QB57! It’s an unique little air rifle and the performance is really very good for such a low cost air rifle. And - being made of real “tree wood” and steel, there’s much potential for tuning and customisation.

I hope that you’ve enjoyed this review of the QB57. Try one, you may find it a lot of fun :-)

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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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