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06 April, 2013

QB78 Repeater First Test Target

Here's some initial performance data for the QB78/QB79 Repeater.

During our functionality testing, we've seen strong muzzle velocities and good accuracy with all QB78 Repeater and QB79 Repeater test "mules". However, Paul made a first controlled "Gold Service" test this week and the test target is shown here. The gun was .22 caliber QB79 Repeater "mule" number 3 and the pellets, Crosman Premier Lights. Double click the target to see a bigger view.



As you can see from the test target above, the muzzle velocity achieved was 621 fps at just 60 degrees F. Given other experience of QB78 performance, this allows us to predict possible muzzle velocities for the QB78 Repeater and QB79 Repeater.

Based on this data, we would see a muzzle velocity for this gun of about 630 fps in .22 caliber at 65 degrees F (our normal testing temperature), climbing to 660 fps at 80 degrees F.

The equivalent muzzle velocities in .177 caliber would be about 730 fps at 65 degrees F and 760 fps at 80 degrees F.

This is a first "hard" data point for the QB78 and QB79 Repeaters. We'll make more tests before deciding on specific muzzle velocity specifications for these new models.

And one other point. Please look at the Standard Deviation. It's just 2.00 fps. Paul fired at a steady rate and wasn't timing, but he certainly completed the string in less than a minute. This indicates that the QB79 Repeater may not be seriously troubled by falling muzzle velocity with rapid fire which is, of course, inherent in all CO2-powered air rifles due to the high capacity of the 9-ounce tank.

Accuracy is proving to be excellent, as you can see with this 10-shot group. The longer breech with twin - and much longer - barrel setscrews is the probable cause for this.

We'll publish more test results as they become available.

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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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