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17 October, 2010

Stop Jawing About It and… Just Do It!

By Ron Robinson.

Recalling how excited I was to discover organized airgun competition and how quickly I jumped at the chance to enter my first silhouette match, it seems strange how many airgun enthusiasts procrastinate and/or are intimidated to enter their first silhouette or field-target competition. Perhaps it’s performance anxiety (fear of a poor showing), but many airgunners simply cannot seem to “pull the trigger” (so to speak) when it comes to entering their first match. Many are attracted enough to these airgun games to participate in on-line forums with posts and questions, yet are apparently repelled by some unexplained force.

While I can see why one might be hesitant to attempt such a demanding discipline as ten-meter competition, reactionary-targets like silhouettes and field-targets hardly lend themselves to structured venues or up-tight participants. And while I’ve heard field-target shooters referred to as “elitist”, truth is the only “elite” thing about them is their shooting skills.

After years of field-target and decades of airgun silhouette experience, I can state unequivocally that neither discipline attracts a pretentious following, and the term “discipline” is in fact a misnomer for either game. A much more accurate description than the “elitist” comment mentioned above was overheard from a spectator at a Texas State Silhouette Championship, “It’s a bunch ‘a grown men shooting BB guns at little metal animals!” How intimidating can that be?

To the silhouette and field-target-curious out there in Airgunland procrastinating their first competition out of whatever misguided fear one conjures to avoid discovering some of the best airgun fun to be had with like-minded individuals, I feel compelled to give one piece of advice.

"Try it... you'll like it!"

A pretty up-tight bunch - just look at those scowls!


11 October, 2010

Keep Powerlets in Your Pocket, Gain 20fps Muzzle Velocity With Your QB78

Here's some test results that show why you should keep 12 Gram CO2 Powerlets in the pocket of your jeans before loading them into your QB78 family air rifle. Oh yes, and then wait for 3 minutes before beginning to shoot. It can make 20fps difference to muzzle velocity!

I made 10 tests, each time loading a QB78 air rifle with two full standard 12 Gram Powerlets. In every case, I had warmed the Powerlets in the pocket of my jeans for about 30 minutes beforehand.

The table below shows (from left):
1) The ambient (room) temperature.
2) The initial temperature of the gun before loading Powerlets.
3) The temperature of the gun immediately after the warm Powerlets were loaded.
4) The temperature of the gun immediately after piercing the Powerlets.
5) The temperature of the gun after waiting 3 minutes.

On average, the guns started at approximately room temperature - 67 or 68 degrees.

After running this test a few times, it occurred to me that I should be recording the temperature increase of the gun after I loaded the Powerlets that had been in my pocket. Duhhh...

So, we can see that the temperature of the gun rose by about 7 degrees F immediately after loading with the warm Powerlets.

Piercing the Powerlets caused the temperature of the gun to fall by 10 degrees. Gun temperature stabilized at about ambient temperature again after 3 minutes in ambient temperatures of 65 to 70 degrees F.

So, what do we learn from this data?
- Keep Powerlets warm before use.
- Wait for at least 3 minutes before starting to shoot your gun.

The reason for all this interest in gun temperature is that the muzzle velocity of QB78-family air rifles - like all CO2-powered guns including the Crosman 160 - changes with temperature. For the QB78, this change is 2fps per degree F. So we see that just piercing the Powerlets in your gun causes the temperature to fall by 10 degrees F. That represents a FALL in muzzle velocity of 20fps!

For those of us wanting the best performance from our Q78s, that 20fps makes a big difference, not just to muzzle velocity, but also to the point of impact.

Doubtless, the results would be different in higher ambient temperatures (and the differences less marked), but 70-ish has been about the best we have been able to manage in Up-State New York recently. Conversely, I would expect the effect to be more marked at lower ambient temperatures.

The gun temperature readings were made using the Archer Airguns Temperature Monitoring Kit for QB78.


07 October, 2010

Spring Air Rifle Test Results - Stoeger X50 and QB57

As several folk sent emails saying they found previous "Gold Service" test targets interesting, here's a couple more that have just gone through the shop.

The first shows the test target for a .177 caliber Stoeger X50. Here we can see the excellent accuracy out of the box - if I do my part! - displayed by all the X50 guns I've tested so far. As with almost all of these guns, there was no dieseling at all and the Standard Deviation (muzzle velocity variation) is excellent for a brand-new springer.

The X50s shoot at approximately 1100fps with CPLs, giving 20+ ft/lbs of muzzle energy. The trigger pull weight on this Stoeger X50 was a little above average, most show less than 5lbs pull weight, but it still felt fine and gave predictable let-off.

By way of a comparison, we have a test target for a QB57 Deluxe in .22 caliber. As is Archer Airguns practice, the gun was tested with my trusty Leapers red dot scope.

Some QB57s can be very "wet" from the Shanghai factory and show considerable dieseling when first fired, but this one was nicely dry and gave outstanding figures of only 5.38 ft/sec over 10 shots. This is QB78 territory!

Trigger pull was very light, too, at only 3 lbs 3 oz. QB57 triggers have a long pull, but a little experience makes them quite predictable. And nearly 10ft/lb of muzzle energy in an accurate, controllable package is pretty good for such a compact air rifle that sells for less than $75.00 and has so few plastic parts.


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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