Edgun FPS Change "SOLVED". Edgun Owners Read

A week or so ago, I noted how it seemed that my Edgun was changing fps from day to day. Ed suggested I clean the barrel, and I did, and that seemingly fixed the issue. But that was not the cause…

Yesterday at the range, I was tinkering with the hammer spring adjuster; trying different pellet speeds to see which speed grouped the best. I settled on a very fast speed – 940-950fps. I was shooting 20 shot groups to make sure I wasn’t just getting lucky.

So, here’s how the events played out. I adjusted the hammer sping to maximum minus one half turn. I filled my Edgun to 205 bar. I then shot 20 pellets over the chrony. The average was around 948 for 20 shots. I didn’t keep firing pellets because I was afraid I would run out before I had a chance to do all the testing I wanted.

I did this for multiple hammer spring adjustments, and noted in my log what the first 20 shots were for each hammer adjustment (one half turn increments). Each 20 shot started at 200 bar and ran to about 170 bar.

Then when I was ready to do the accuracy testing, I simply adjusted the hammer spring to each known FPS setting. (note, I could not simply do the chrony testing while I was doing the accuracy test because the range was shaded too much for the chrony to work properly). But, by the time I started with my accuracy testing, my 4500PSI tank was starting to dip below 200 bar. I was only getting fills up to 190bar. No big deal, I thought. The gun will hold the FPS to at least 140 bar.

But, there was an unknown element at play….

When I tested my gun over the chrony earlier today (filled to 194 bar – the most I could “squeeze out of my tank) it was shooting at around 930fps (down to about 135 bar, where it then dropped off steadily). That is about 20fps lower than yesterday’s chrony readings. I scratched my head, and chalked up the difference to the idea that my chrony was malfunctioning. Which reading was the “real” one, yesterday’s or today’s – I did not know.

But, this could mean that my best group may have been in the 930fps range yesterday (not 950fps). I need to know what was going on…

I was planning to figure it out at the range on Sunday. But, to do that, I would need more air. So, I went and got the 4500PSI tank refilled. I came back home, filled the gun to 204 bar and tested it again. This time the gun was shooting at 950fps right out of the gates. And it held that speed until about 170 bar, when it suddenly returned to the 930fps range. It held high 920’s until around 135 bar (like it had earlier), and then steadily dropped off again.

I was starting to see a pattern. I filled the gun back up, but only to 188 bar (not 200+). This time, the fps locked right in at 930 fps, and held there until 135-140 bar where is started to drop off.

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So, in summary:

At my current hammer spring setting (which is high), if I fill my Edgun to 200 bar or more, it seems to fire “hot” for about 20 shots, before returning to the “normal” speed at around 170 bar. But, if I fill to around 190 bar, the fps starts at 930fps and stays there until the gun pressure reaches 135-140 bar – giving me around 40 very consistent shots at around 930fps. I was able to repeat both shot strings by filling to 200 vs. 190 bar.

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So, I put this information in your hands. See if this same phenomenom happens to your Edgun. It may be specific to my gun. Or, it may be because of the high-energy setting I am using.

Whatever the answer, this seems like VERY useful information for Edgun owners.

I want to make clear that this is NOT a complaint. I simply like to understand my guns inside and out, so that I can more effectively ring every last bit of accuracy out of them. And I have opted to share what I have learned about my gun, in hopes that it could potentially help other Edgun owners.

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And of course, I welcome the thoughts of the manufacturer. 😉

Ted 🙂