Today Doug Wall explores unregulated Barra 1100z performance in .177 Caliber. He’s using the Gen. 1 gun that started-out in .22 caliber.
Having made the caliber change, Doug’s testing follows the same methodology as he used for Part One of this saga. This enables to compare the performance of the same gun in different calibers. It’s also a new baseline to compare with the gun’s regulated performance in a future installment.
Today’s Testing
In this part, I’ll go through a similar set of shot strings as in part one, to see the effect of hammer spring adjustments on velocity, shot string, and energy. As mentioned before, my goal is to get the gun set up at just under 20 Ft/Lbs energy.
As in the previous article, I will be starting the pressure at about 3,000 PSI, and going down to about 1,500 PSI.
Again, for as much compatibility as possible, I’ll be using H&N Baracuda pellets. This time it’s the 8.44 Grain Baracuda 8. These were also a HAM Gold Award winner for their manufacturing consistency.
There’s no point in testing with low quality ammo!
I like these pellets and have found them to be accurate in many of my personal air rifles. For that sub-20 Ft/Lbs requirement, we’ll need to have these pellets traveling with a maximum Muzzle Velocity of 1,030 FPS.
Barra 1100z Performance – Power Tune
Shot string one is at the previous “power tune” setting of about eight turns in. Again, we see a relatively small number of high-powered shots with a constantly-dropping velocity.
As with the .22 caliber testing, now we’ll take the same graph and add pressure gauge readings to it (the purple bars). As we can see, both pressure and FPS drop together.
Although this may be a reasonable hunting tune, it’s clearly unsuitable for my 20 Ft/Lbs Field Target goal. No surprise there!
Barra 1100z Performance – The Field Target Setting
The second series was shot with the hammer spring adjustment screw three turns in from flush.
Here we see an absolute maximum Muzzle Velocity of 1,025 FPS. That’s 19.69 Ft/Lbs Muzzle Energy and definitely Field Target legal. Hey, we got lucky first time. I’ll take it!
In HAM testing, we consider an Extreme Spread of 40 FPS to be “acceptably consistent” Muzzle Velocity for an unregulated air rifle. That’s because there’s no perceptible elevation difference in impact at 55 Yards – maximum Field Target range.
That means shots below 1,025 FPS and above 985 FPS count as “consistent”.
As we can see from the chart, this tune gives 23 “consistent” shots, starting at shot 38 and running to shot 61 in this string.
The Muzzle Velocity/fill pressure graph above shows that our unregulated Gen. 1 Barra 1100z performance is “Field Target ready” with a fill of 2,400 PSI on this tune setting.
However, that number of consistent shots means that we’ll need to re-fill three times during the typical 60-shot match. I’m hoping to find this level of power but with a lot more consistent shots after installing the regulator.
Barra 1100z Performance Best Overall Performance
Now for the “five turns in” setting – approximately the factory setting.
As we can see, this is definitely a good general-purpose tune. Again, we have 23 “consistent” shots, from shot 6 to shot 29. But this time the fill pressure would be 2,800 PSI.
However, it’s too powerful for Field Target.
1100z Gen. 1 PCP Performance Comparison .177 Caliber
Again, we’ll take the Muzzle Velocity curves for the three hammer spring settings and plot them together, we have a graphic comparison of what’s happening.
1100z Gen. 1 PCP Total Power Comparison
Now let’s compare the same tune settings for our gun in .22 and .177 calibers.
Here, I calculated the Muzzle Energy for every individual shot in these tests. Adding them together for each of the tunes we can compare the total power produced for each fill of the gun from 3,000 PSI down to 1,500 PSI.
| Hammer Spring Setting | Shots Per Fill .22 Cal | Shots Per Fill .177 Cal | Total Energy .22 Cal | Total Energy .177 Cal |
|---|---|---|---|---|
| 3 Turns In | 53 | 72 | 1,070 Ft/Lbs | 1,166 Ft/Lbs |
| 5 Turns In | 50 | 46 | 1,135 Ft/Lbs | 912 Ft/Lbs |
| 8 Turns In | 28 | 31 | 728 Ft/Lbs | 629 Ft/Lbs |
So what happened with the “five turns in” tune in .177 caliber? There’s less shots per fill than when the gun was in .22 caliber!
I don’t know. But – hey, that’s why we test this stuff in a consistent manner at Hard Air Magazine!
In the next episode of this saga, Doug Wall moves on to install a regulator.
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Barra 1100z Air Rifle
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