Edgun fps changing from day to day – hour to hour???
My Edgun came shooting @ 920fps (as recorded by my lighted chrony in the basement). A few days later, at the range, I felt like it was shooting more slowly. I didn’t have my chrony with me, but noticed that I had to hold over by an extra dot at 100 yards. When I got home, I tested the gun on my back porch in the shade – the chrony said 880 average. So, I upped the gun back to 910 average.
Today, I went to the range again, and the chrony said the gun was shooting at 950 average. I believed it because they pellets were laying down 1″ groups at 50 yards, and I know it can do better. When the gun got to 110 bar, and the chrony reported 910fps, the groups went back to MOA. I even went out to 100 yards, and shot two groups – one at 150bar (950fps) and one at 110bar (910fps). The one at 950 was just over 2″ – the one at 910 was my first sub MOA group with this gun.
When I got back home, I went to the backyard to dial the gun back down. I filled it to 180 bar and took a shot…912fps. Took another – 906fps….907…902…905…906….
What could be causing this? Batteries are fine in the chrony. I really think it is the gun. After you shoot it 500 times and make power adjustments, you get a feel for knowing the sound for each speed – or, at least I thought I had a feel.
The accuracy and chrony reading sure had a strong correlation. So, what could be causing this significant change in speed (40fps)?
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One more thing Ted, pull the stock off and check to see if the screw that
locks the hammer spring adjustment screw is snug… I had that screw come
loose on my Lelya and it threw me for a loop for a while…..
😀
You avatar is cracking me up…
“We have a high pressure system penetrating the middle of the Ohio.” 😆
Thank you guys. I will follow all of your advices, and report back my resolution. 💡
Last month the humidity where I live changed from an average of 60% to 45% in what appeared to be a weekend. Local speed of sound varies depending on elevation, temperature and humidity…
Don’t Chrony in different conditions and expect the same results.
1st Test- Basement (lightbulbs) 920
Feels strange at the Range.
2nd Test- Back porch (shaded daylight) 880@?bar
Changed power setting (UP).
3rd Test- Range (daylight?) 950 @150 bar/910 @110 bar
4th Test- Back Porch (shaded daylight) 910@180
Looks correct to me if you only look at the porch data and the adjustments… Reads 880 at back porch, you upped it, ignore range data, go back to porch, 910.
What’s the problem?
Your chasing your tail mixing up your location based chrony data.
Your readings appear slow on the porch when compared to your range readings, this would concur with the basement reading.
Try this:
Start in one spot, take readings (velocity, tank start and end pressure, temp, humidity and location elevation), set the power, take readings.
Go to the other spot and test, do not adjust.
Go back to original spot and take readings.
Verify original readings.
If a change happens then look at temp, humidity and elevation readings. If they are constant then problem may be gun related.
If no change happens then it’s location based.
Go to the other spot, adjust gun until it feels right.
Go back to original location and take all readings.
Compare notes…
Readjust as needed and take more readings (start at step one)…
😉
First of all try to clean the barrel carefully, 500 shots as you say can be lead in the barrel and you need to remove it. When you do it, give the gun about 30-50 shots to get barrel used to pellets again and then check the speed.
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Thanks, Mam. I made sure it was snug (but, not too snug – as Ed says in his videos “just to touch, and then a little more”.
I took the gun back to the range this afternoon. Whatever was causing that drift was seemingly gone. I dialed the gun in at 910fps, and proceeded to have fun shooting dime groups at 50 yards. As I burned through a 250ct tin of JSB’s, the accuracy started to waiver. The gun would stack 3 in one hole, and then send a couple an inch or more off at 50 yards.
I decided the barrel must be getting pretty dirty. I’ve probably put about 1000 rounds though it, and I’m embarassed to say that I never even cleaned it for the first time when I got it from Tony. So, this was my first cleaning.
I melted the end of a strand of 300lb monofilament and patted it on the table until the diameter was .22″. Then I poked a cleaning pad through the tip, slid it to the “butt” of the monofilament, gave it a drop of Otis cleaner, and pulled it through the barrel.
It was so dirty that it wasn’t even grey – it was shiny silver! And it had actual flecks of lead on it. Three or four more pulls looked the same, and I had to run about 20 through until the gunk finally stopped coming.
That filthy barrel must have been giving me the accuracy issues. The rifling was probably so “clogged” up that it wasn’t spinning every pellet the same. Does that make any sense? Or am I talking out my butt? 😆