Air Venturi Newbie Question: Avenge-X .177

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drpietrzak

drpietrzak

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Jul 17, 2022
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While I have shot springer for about a year or more now I decided to try a foray into PCP. Just because. As the compressor thing is bit of a speed bump I thought I would start reasonable. I watched a lot of videos and decided to start with an Avenge-X in .177, For under $100 I can switch calibers later if I want to do so. In any event, I decided rather then try and get in over my preparation I would shoot it as it arrived for now. There are 2 or 3 videos I watched that suggested that the regulator would be "high" for the first couple of shots after a fill and then settle. Si I checked that out with mine and that appears to be the case. With the setting on "high" with AA 10.3 (4.52) unsorted pellets I saw this string. It was repeatable. After a fill it is at about 2000psi. After a couple shots it is about 1800 psi and then stays pretty stable.

967.9
959.9
954.5
953.1
953.1
954.5
954.5
950.2
951.6
956.0

Switching to low after a couple shots for transition I saw:

827.6
828.7
826.5
826.5

Question: What causes this to happen. Now this is just for educational purposes. I currently am not looking to do anything with the rifle, rather just better understand it.

Testing several pellet types at 50-yards saw several group in the 0.08" to 1" range. Benjamin Match 10.5s grouped the tightest at 0.69", 0.82" and 0.63" for unsorted pellets. No, I did not chrono those. This seems OK to me for a start.

ben 081824.jpg
 
Last edited:
Here's wh
Avenge X 25 cal 1800

Fx 25 25.4 gr

Weather: 95.6°F 3.0mph clear sky 1013hPa/mbar 29.91inHg 47%

Shot count: 32
Low: 867
Hi: 878
Avg: 874
STD Dev: 3
Spread: 11

8/17/24 2:48:14 PM,878,FPS,43.5,FT Lbs,
8/17/24 2:48:24 PM,874,FPS,43.1,FT Lbs,
8/17/24 2:48:49 PM,873,FPS,43.0,FT Lbs,
8/17/24 2:49:06 PM,874,FPS,43.1,FT Lbs,
8/17/24 2:49:15 PM,873,FPS,43.0,FT Lbs,
8/17/24 2:49:23 PM,873,FPS,43.0,FT Lbs,
8/17/24 2:49:49 PM,870,FPS,42.7,FT Lbs,
8/17/24 2:50:01 PM,872,FPS,42.9,FT Lbs,
8/17/24 2:50:33 PM,877,FPS,43.4,FT Lbs,
8/17/24 2:50:53 PM,874,FPS,43.1,FT Lbs,
8/17/24 2:53:12 PM,874,FPS,43.1,FT Lbs,
8/17/24 2:53:41 PM,875,FPS,43.2,FT Lbs,
8/17/24 2:53:51 PM,877,FPS,43.4,FT Lbs,
8/17/24 2:54:03 PM,872,FPS,42.9,FT Lbs,
8/17/24 2:55:21 PM,875,FPS,43.2,FT Lbs,
8/17/24 2:55:34 PM,869,FPS,42.6,FT Lbs,
8/17/24 2:56:02 PM,874,FPS,43.1,FT Lbs,
8/17/24 2:56:12 PM,875,FPS,43.2,FT Lbs,
8/17/24 2:56:32 PM,867,FPS,42.4,FT Lbs,
8/17/24 2:56:47 PM,874,FPS,43.1,FT Lbs,
8/17/24 2:56:59 PM,870,FPS,42.7,FT Lbs,
8/17/24 2:57:12 PM,868,FPS,42.5,FT Lbs,
8/17/24 2:57:22 PM,875,FPS,43.2,FT Lbs,
8/17/24 2:57:36 PM,874,FPS,43.1,FT Lbs,
8/17/24 2:58:11 PM,874,FPS,43.1,FT Lbs,
8/17/24 2:58:21 PM,877,FPS,43.4,FT Lbs,
8/17/24 2:58:30 PM,877,FPS,43.4,FT Lbs,
8/17/24 2:58:54 PM,874,FPS,43.1,FT Lbs,
8/17/24 2:59:27 PM,874,FPS,43.1,FT Lbs,
8/17/24 2:59:36 PM,872,FPS,42.9,FT Lbs,
8/17/24 2:59:43 PM,874,FPS,43.1,FT Lbs,
8/17/24 2:59:49 PM,874,FPS,43.1,FT Lbs,


at My Avenge X 25 cal, does with Fx 25.39 gr pelletts Regulator set at 1800 psi.
 
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drpietrzak said:
After a fill it is at about 2000psi. After a couple shots it is about 1800 psi and then stays pretty stable.

Question: What causes this to happen.
Click to expand...
It’s the imperfect nature of real-world regulators. They don’t hold the pressure perfectly consistent, especially when the reservoir is near max pressure and it has been idle for few minutes or hours. High pressure air continues to slowly work its way through microscopic imperfections in the valve seat until the plenum pressure eventually rises high enough to squeeze the seat hard enough to completely halt the flow of air.

In a typical shooting session, there’s not enough time for the pressure to creep up a meaningful amount. A reg will usually replenish the plenum to a pretty repeatable pressure within 1-5sec, after which it will creep up very slowly over a period of minutes or hours.

Adjusting the hammer strike to deliver about 97% of the maximum possible velocity will put the gun in a state of tune that is least sensitive to modest pressure changes.

If or when you want to research the topic in more depth, I have a few related threads linked in my profile.
 
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nervoustrig said:
It’s the imperfect nature of real-world regulators. They don’t hold the pressure perfectly consistent, especially when the reservoir is near max pressure and it has been idle for few minutes or hours. High pressure air continues to slowly work its way through microscopic imperfections in the valve seat until the plenum pressure eventually rises high enough to squeeze the seat hard enough to completely halt the flow of air.

In a typical shooting session, there’s not enough time for the pressure to creep up a meaningful amount. A reg will usually replenish the plenum to a pretty repeatable pressure within 1-5sec, after which it will creep up very slowly over a period of minutes or hours.

Adjusting the hammer strike to deliver about 97% of the maximum possible velocity will put the gun in a state of tune that is least sensitive to modest pressure changes.

If or when you want to research the topic in more depth, I have a few related threads linked in my profile.
Click to expand...


Thanks!
 
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