Just getting back into air rifles. I shot mine using the chrony yesterday. I have the old style where you have to shoot over the chrony between the poles that holds the sunshades. Because I was shooting under the cover of a roof the chrony at the end of the bench a few feet from the muzzle would not record the shot. So I had to place the chrony about 5-7 yards into the range in the sunlight to get readings. When reporting velocity of the pellet the number provided by manufacturers, retailers and I assume owners is "muzzle" velocity. Question: Does the distance of 5-7 yards significantly impact the velocity number to be less than the number generally published by the above? I am not discussing different pellets producing different performance stats-just the chrony distance from the muzzle. Obviously if the chrony is 25 yards away the stats are the terminal velocity and you will probably have a "terminal" chrony at some point.
Using the Chrony
- Thread starter bowzette
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I would say that 5 to 7 yards would still be an accurate enough reading unless it is a very very light shooting gun .
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My 25 shooting 34 gr drops from 924 to 907 in the first 7 yards. Take that for what its worth
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I have springers. My LGV .22 (12 fpe rifle) with mid weight JSB 14.35 pellet was 576 fps average at say 6 yards. This is 10.6 fpe. From an alleged 12 fpe rifle.
I have a FWB 300s mini, and R7 in .177 and they each averaged 570/580 fps with 6.22/6.31 fpe. So compared to much higher performing air rifles 6 yards may be significant. Next time hopefully I can get closer to the muzzle, but my memory from years ago is I had to have some distance for the chrony to register the shot.
I have a FWB 300s mini, and R7 in .177 and they each averaged 570/580 fps with 6.22/6.31 fpe. So compared to much higher performing air rifles 6 yards may be significant. Next time hopefully I can get closer to the muzzle, but my memory from years ago is I had to have some distance for the chrony to register the shot.
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they are light shooting. Two are around 6 fpe and one is 10.5 fpe. So they start off slow and get slower, but seem accurate.
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Ya.... Look at this chart of fps for a distance . You see it drops fast .
I don't have a fwb . Maybe a lgv . ( No lgu) But here's a R7 to look at
I don't have a fwb . Maybe a lgv . ( No lgu) But here's a R7 to look at
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Move it another 6 feet and see if the difference matters to you. That should the difference between current and actual muzzle.
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A thing I like on that cheap china bolt on crony is it's about at the muzzle as one gets ..lol .
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The standard for a chronograph in firearms testing is 15' so 5 yds per saami standards of testing . I have no idea if airgun manufacturers use any standard when giving velocity specs.
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Because a chronograph is a tool to test consistency and speeds it doesn't matter where you place it, so long as you are at a measured distance from the muzzle and you're using the data correctly. I put mine 10 yards out from the muzzle when testing new ammo and tunes. This data is used to figure out the initial muzzle speed and energy as inputted into Strelok Pro. Sometimes I will shoot a shot or two directly behind the front of the chronograph will verify the initial speed is correct, but hasn't shown that it is needed.
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Mine is an older Shooting Chrony Beta. I generally place it about 6" from the muzzle. I do believe that is why I've never shot the darned thing. And the numbers match up well in Chairgun.
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I'm using one of these right now and I've tested a previous version against a labradar. They are good enough for what we need and cheap. They are far less temperamental than the traditional style.
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careful here - you need to make sure the LEDs are not driven by a PWM circuit (i.e. pulsing on/off really fast). Really cheap ones can be better - as cheaper ones can have less circuitry etc & be a little more wasteful on how they moderate the power.
Also depending on the Chrony - it could be HEAT & not light that is triggering it. This is something really different to work with.
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Maybe not if you're pushing close to trans sonic speeds.
If you're seeing 900fps at 10ft - *maybe* its over 1,000 at the muzzle & causing a lot of instability as it leaves the barrel before settling.
You're 100% correct that once you're in a good spot or adjusting from a known tune you'll be fine. Maybe that first tune or two could be a bit difficult to find out you're running too hot.
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True, but LED strips are just strips of LEDs. The power supply can be batteries, if needed (e.g. 8x1.5v = 12v). Cheap 12v power supplies could also do.
There are people who stick whole battery powered LED work lights but those do have PWM and would most often not work.
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True!
12v supplies will almost always be PWM - be careful, batteries (& a resistor/diode) would always be the best bet.
The cheap work lights used to be perfect when i used my old chrono - just had to find cheapies that didnt flicker
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These are some better quality, but still like $7 LED strip lights and a cheap USB power bank. Some power banks won’t work correctly, and will only show error. This works very well and I trust it more than my FX chrony.
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