Edgun R3 .22: Shot String, Air Efficiency, & Trigger
This will be a long post, sorry about that. Ran into the dive shop to fill up the scuba tank yesterday. The shop owner put on a pressure gauge to show me how much the tank was filled, because I was “hinting” at him that I could only fill the gun to 180 bars (~2610 psi) last time with a full tank. The tank was indeed filled to the maximum pressure around 3100 psi in this new fill. Interestingly, again, I only could fill the gun up to ~180 bars based on the gun gauge; but the gauge in the fill adaptor showed 3050 psi (~210 bars). It seems that the pressure of my Edgun was somewhat under measured by 440 psi or 30 bars. 🙄
I tested a shot-string using Combro Chronograph, which is a very small and handy chronograph installed at the end of the muzzle area. The starting pressure was 180 bar (based on Edgun gauge) and JSB Heavy (18.1 grains) was used. The first shot was low in speed (878 ft/sec), but the subsequent 35 shots were consistent with average 916.5±4.5 ft/sec (minimum 910 ft/sec and maximum 926 ft/sec). The regulator came off around 130 bars (I think) because of a little rise in speed for several shots and then the speed dropped to around 840 ft/sec for about 13 shots in parallel with pressure drop. The POI (at 30 yards) started to drop slightly (~0.2”) at shot #37 (or the regulator was off at this point?) The POI didn’t further drop until pressure went below 105 bars. I got 35 good shots consuming ~800 psi (from 180 bar to 125 bar) from a 289-cc air tube with average 33.8 foot-pound muzzle energy, which is about 13.1 bar-cc/ft-lb efficiency of air usage. If using Zoco’s data – green-line shot string, 220 bar to 130 bar for 57 shots, ~32.5 fpe (http://talonairgun.com/forum/viewtopic.php?t=19488&postdays=0&postorder=asc&start=520), I got the number 14 bar-cc/ft-lb efficiency.
Based on the data from a shot-string of Royale 400 (without regulator; average 868 fps with 37 fps extreme spread) (http://www.network54.com/Forum/79537/thread/1318702313/FX+Royale+400+.22+-+90+shot+string+with+chart-target), which consumed 0.94 bar/shot (220 to 135 bars for 90 shots) with ~30.3 fpe from a 400-cc bottle, the air efficiency is 12.4 bar-cc/ft-lb. Using another shot-string (http://airgunadvice.net/viewtopic.php?t=12183), from 220 bars to 179 bars with 36 shots (average 954 fps with 28 fps spread) at ~36.6 fpe, I got the same number (12.4 bar-cc/ft-lb) for air efficiency. Using the data from the FX Royale 400 review video of Ted in Youtube, average 33.53 fpe and 20 fps extreme spread with high power, I got 11.1 bar-cc/ft-lb efficiency. If the medium power is used (884 fps with 31.4 fpe and 13 fps extreme spread), the efficiency will be higher at 9.6 bar-cc/ft-lb. It seems Royale is a little bit better than Matador R3 (standard length) in air efficiency without much sacrificing speed variation in the un-regulator gun.
I think Edgun can be optimized by adjusting the combination of regulator and power to reach max efficiency, but it will need a lot of trial. Or this is already at the optimal condition when Ed designed and set up the gun. What do you think?
p.s
I also installed a Harris bipod BRM-S model 6”-9” in late afternoon, and ran a few shots under high-gust wind (>20 miles/hr) before dark. It seems to improve the unstable sitting of the gun and increase the shooting accuracy. 😛 Will test more tomorrow if weather is good.
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😯 😯 😯
2,5 K per month since last May is veeeery impressive !!!! 😀
I’m not even halfways I’m afraid……. 😳
Yeah, I’ve been slinging ALOT of lead at targets and game. I have appx another 30k JSB 18s on shelf now.
I may break it down before the Western States match for thorough internal cleaning and inspection. But then again it’s running perfect so I may not.
😯 😯 😯
2,5 K per month since last May is veeeery impressive !!!! 😀
I’m not even halfways I’m afraid……. 😳
endothelium
I did mark the reg with the factory setting. I will give it a try and will let you know what happens. Can you elaborate on why this might work?
Strietwise,
Give this a try to see if it helps. Turn the reg screw counterclockwise passing the stock setting (I hope you do have marked the location) by half-turn, then turn the screw clockwise to 5:00 location. Hopefully 5:00 is the place close to where you need for the speed. Make sure there is no blockage on the air passes in the reg. It should reach the level as described by Dennis if the gun is stabilized.
Please keep us updated on this.
Endo
How many shots do you have on that new 22 long?
Wait until a couple thousand before you start messing with reg. Let it break in. Mine didn’t settle first couple thousand and it really locked down past 5k or so pellets.
My reg is at appx 1/2 turn down and HST almost full turn off from stock. JSB 18s came at 950 fps stock.Now JSB 18s @ appx 880fps with 2.66 SD , 9fps max spread for appx 115 shots. I’ve got little over 25k pellets through it now.
Any idea of what might be wrong? I have been adjusting the reg and HST and max fps does not change. It is a new M3 long in .22. I want to shoot JSB 15.9 about 940 fps. Out of the box it was shooting 1050 fps. Turned the reg to 3:00 and was getting 980. Turned reg to 9:30 and got 800fps. Then 6:00 and got 870fps. 4:30 and got 870. Then 3:00 and still 870 fps. Each time I backed out the HST 2.5 full turns and then worked it back in to find max speed. What gives? Why am I stuck on 870? A six pack to anyone who can help. Thanks.
…you can also find it on Ebay.
You can order it from their website:
http://www.chronoscopes.com/
IMHO, the Combro is excellent for indoor usage since it is not affected by lighting conditions. Combro is small enough to be put into the pocket and bring it to anywhere you want to shoot. Since it is installed right in front of the muzzle, this may change POI slightly. Once installed, I re-zeroed the gun. I can easily get the relationship between speed and accuracy of the gun. Several months ago (more than one year after purchasing), I found my Combro was off by more than 30-40 fps. I contacted Chris in Combro and he asked me to send it back. He checked the sensors and found one of them was slightly off in calibration. He sent me a new Combro, including batteries, right away free of charge – outstanding customer service.
Endo
Where can we buy one of these gizmos? Thanks.
Thanks a ton Endo. It’s kind of ironic, but I am sitting here now reading about them and just found one on ebay that ships from Canada. Looks like a good fit for my shooting conditions.
HookEd,
IMHO, the Combro is excellent for indoor usage since it is not affected by lighting conditions. Combro is small enough to be put into the pocket and bring it to anywhere you want to shoot. Since it is installed right in front of the muzzle, this may change POI slightly. Once installed, I re-zeroed the gun. I can easily get the relationship between speed and accuracy of the gun. Several months ago (more than one year after purchasing), I found my Combro was off by more than 30-40 fps. I contacted Chris in Combro and he asked me to send it back. He checked the sensors and found one of them was slightly off in calibration. He sent me a new Combro, including batteries, right away free of charge – outstanding customer service.
Endo
Thank you endo…I was wondering because I have some green/white chrono f1 and I haven’t gotten it to record consistently enough to get a good solid string without all sorts of errors. I have to be able to use it indoors. I hung a long light above it and tried it with and without the shades several different ways. I get a good string going, then I get all sorts of errors lol. Just frustrating so I may get a different one that I can use inside better…or, maybe I need a different light?
Tedd, thanks for the instruction. This is what I thought too, and is on my “To-Do List”. Just need to find a time to do it.:)
Hooked: Regarding chronograph, I use Combro MK4 and ProChrono Digital. Combro is very easy to use and not affected by lighting conditions. The speed measurement is very comparable between these two, with <3 fps difference in my set up. ProChrono can record 9 strings with 99 shots for each string, and you can review the string easily with statistics in SD, Extreme Spread, as well as mean, highest/lowest velocity.
Endo
May I ask , “what chrony are you guys using for your shot strings”?
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endothelium
Well a gave your suggestion a try and no luck. I am still stuck on 870. I just read something OldGoat wrote about checking the brass nut the valve stem goes through to make sure it is not loose. So I will check that and if that is not it I will set the reg back to 12:00 and see what happens. What ever it is when I figure it out I will post it here.