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Ideal ES for shot count

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Point1Seven

Point1Seven

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Sep 29, 2018
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What is your ideal ES? What range do you like to stay in and why? .177 caliber and .22 caliber only



I have always done 50fps ES for managing my shot counts in my PCPs so that I see almost no POI change at all. Recently I have been fiddling with one of my redoing my shot string and power levels and noticed at 80fps ES it was essentially the same results as 50fps ES, but instead of getting 27 shots I achieved 41. Quite a huge difference especially if your like me and hand pump only 💪.maybe input will help me change my mind and please not I only shoot out to 60 yards Max.

Rifle used was a Xisico Sentry in .177 caliber shooting 15fpe. (It won't go lower 😭)
 
Maybe I get it now. Are you asking how much to let the velocity drop before refilling the rifle? If so, those numbers look a little high if you are interested in precision accuracy. I would think at a 50 fps drop, you would see a POI change at 60 yards. Also, if you are going to count shots before filling, you need to build in a cushion, because I don't think you will find that it is consistently repeatable. 
 
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At 50 I notice no difference out to 60 yards yards as of now but maybe I'm slowly compensating for it lol. So if it's 20fps I'm yeilded like 3 shots then. But wow you guys are strict. I had a kral mega that did a 30fps ES over 90 shots and I shot it regularly out to 100 with no issues so I'm sure 20 would be great. I think I'll stick to getting a high end springer and shoot my PCPs for giggles lol
 
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Really depends on multiple factors... for example: The BC has an effect on the drop, lower BC with same ES will have higher drop. Starting FPS will also have an even bigger impact, meaning if you start off at 900FPS down to 850 VS starting at 800 down to 750.

Just some real examples:

Assumption: Shooting JSB 18.13gr zeroed at 45 yards

BC effect (950FPS start, 900FPS end): at 60 yards assuming a 0.035BC the pellet will drop 1.72in at 950FPS, once at 900FPS the pellet will drop 1.93in, a total of 0.21 in POI shift. Now assuming same as above but BC of 0.014 at 950 the drop will now be 2.95in and at 900FPS that drop will have increased to 3.26in, so a total shift of 0.31in or roughly a 50% increase

Initial FPS effect keeping BC constant at 0.035: We already know from above the info for the 950 to 900 spread, now lets start off at 850 down to 800.. At 850 the drop is 2.20in and at 800FPS that drop increased to 2.53in or a total POI shift of 0.33in.

Bottom Line: The ES can be as much as you want it to be as long as you are able to achieve the accuracy and consistency you are after. If your gun is capable of a 1/2 MOA group at 60 yards (~0.3in) at consistent FPS then a 0.3in shift in POI would open that group to 0.6in or a full MOA.


 
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Wow great info guys! The percentage thing makes sense and so does the FPS I totally forgot about it. My old gun shot at 905 on the regular so dropping 30fps probably made little difference. Now I'm shooting in the 830fps mark with this rifle so maybe I do notice it more but just don't pay attention as much. My PCP pretty much shoots squirrels at 10 to 30 yards that's it. Target shoots out to 60 lol. But I love the info and food rule of thumb
 
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