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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Kazz, you may be correct. I shot those groups not under “perfect conditions” (about 5-7 miles winds in the wood). Human errors and other factors always need to be considered because I have obtained much better, as well as worse, groups in that range of distance before. I admit that I am not a good (=consistent) shooter. What I can say at this time is 5.47 mm JSB heavier pellets “consistently” did worse within a shooting session. Of course, I also had some groups from heavier pellets, which did well but are just not consistent enough to convince me to use it if I have a choice. I would say that I will have a better luck if not using 5.47 mm heavier pellets. On the other hand, 5.50-5.51 mm pellets are more consistent in grouping (e.g., hole in hole as you said at 30 m) than 5.47 mm ones, regardless the weight of the pellet (17.9 ~ 18.2 grains), for my Matador. I don’t know why the variability is increased with smaller head size. I also should say all my comparisons are relative and empirical, not absolute.
Yes, the differences would be easier to tell at 50 yards. Unfortunately, I have to do that when my neighbor is on vacation (I need to “borrow” part of his backyard for that distance). 🙁 I envy you having that “tunnel bunker”… .:wink:
Is there any new competition coming up to make us proud as Matador owner? 🙂
Regards,
Endo
All have to do with the time the pellet leaves the barrel (so time to make trigger pulls, heartbeats, … is much greater) and the rotation of the pellet giving it a good flight together with the BC of the pellet at a certain speed.
Idd, at lower speeds it is more difficult, but do not forget they shoot almost hole in hole not supported with a 5.5FPE or 7.5Joule gun. I know this gun will shoot benchrested hole in hole at 30m!
I’ve seen that too………..
But I’ve never been able to measure their group sizes though…..
Based on my own experience, – it is much more difficult to get really tight groups with a sub 12 ft/lbs gun than with a full powered one at 30 mts…. 😉
I watched a guy at the FT Nationals knock down a bunch of targets in a strong wind with a 12fpe pcp that the 20fpe guys couldn’t even knock down… 😯
Kazz, not that they are uninteresting, it’s just…..I……what was I doing again? 😆 Must not….stare…..that…..face….. 😆
Kazzz,
Thanks for bringing this up before I did……
As you say, – most any FAC PCP would be able to deliver much better groups at 30 yds almost regardless of pellet. That is if conditions are perfect…
For sub 12 ft/lbs PCPs, – the story may be different though……… 😉
Cheers 😀
Synopsis… you telling me my posts are not interesting enough?? 🙂
ps. the best about this pic is its not all about her tits, her face is even …. as requesting as her tits 🙂
Endo: if I have to be honest, I think these good or bad results at 30 yards are due to your fault.
I don’t know any pcp that shoot that bad at 30 yards. If you bring it to at least 50 yards, you start seeing differences. I bet if I gave you a tin of 5 pellets not telling which are the worst and the best, you will shoot good and bad groups with both at 30 yards 🙂
Kazz, every time I try to read a post your avatar makes it impossible… Please don’t remove it. 😉
Zocoloco,
I agree with you. I used a lot, I mean a lot, of pellets and had to do the tests in the calm days to identify the problems and causes. I envy that Kazzz has the “bunker”…
Kazzz, I couldn’t do any shootings right after reading your posts because your avatar makes me dizzy and I couldn’t stabilize my eyeballs for 10-15 minutes.
I did more tests on the effect of pallet weight on 30-yard shooting, all with 5.47 mm head size and 5-shot group, 30 min after reading Kazzz’s post to eliminate his avatar-syndrome. It appears that the heaviest pallets (>18.20 grain) did worse. The accuracy is 18.10~18.15 grain ≥ ~17.90 grain > 18.20 grain.
Regards,
Endo
And by this you’re invited to come and shoot in my ‘bunker”… 🙂
So we can test our Edguns next to each other together with the cricket.
Great respect for you investigations!
This is sometimes the most interesting aspect of airgun shooting, but sometimes the most frustrating too!
+ 1, – very interesting reading !!! 😀
Key word: equal conditions from one shoot to the next, Impossible to achieve if you’re not indoors and in an environment that is stable….
Unfortunately not too many long range facilities like that around……..
And yes, I don’t know what happened to JSBs these days…… 😥
😀
Mike, thanks for the comments. This is great about this Forum to share info and experience. Have you decided to get a .25 Edgun?
Kazzz, totally agree with you. The most difficult part is to rule out variables one by one, it takes a lot of time to do so since shooting condition is different each time. It is a long journey like the way to Mordor. Consistency is what I am looking for and it will reach accuracy sooner or later, I hope.
I forgot to mention that the Edgun pellets are more consistent in head size than JSB ones (the bad batch I have).
Endo
Endo,
Great respect for you investigations!
This is sometimes the most interesting aspect of airgun shooting, but sometimes the most frustrating too!
Endo,
You have come a long ways Pilgrim! GREAT Post. Should inspire others to try their hand in tuning their own EDguns. The benefit of a fine tune EDgun along with the satisfaction in bestowing confidence in one’s ability to work on his own air gun – it just doesn’t get any better!
Must give credit where credit is due. Hats off to the man himself, ED, for engineering a Great gun that can be easily tuned/balanced. For Endo and others willing to take the time to share posts and experiences and to our own in House Guru (Oldgoat) who has given of himself to any and all to further this sport and the EDgun itself. OK I’m done.
It has been a while not posting report on my Matador R3 .22 standard since adjusting the regulator and speed a few months ago (see my earlier posts). I have been shooting the gun on and off for several months focusing on the accuracy.
In late June, I found the POI was shifted to either right or down by ½” or a little more (30-yard target). There were 2-3 shots with good grope in one point and 2-3 shots with good group in another point. I also found the barrel was pulled toward air tube by a few mm when tightening the trigger guard screw to the stock.
These are what I have done in the past 4 months:
1) Tried to eliminate the barrel shift by shimming the stock in-let (with washers in different locations) and/or the Air-Tube band (with thin plastic film) between air tube and barrel. Tedd was very helpful for providing information on how he shimmed the air tube. The shimming improved (reducing some horizontal shift or some flyers) but did not solve the problem of POI change.
2) Changed the scope rings to Burris Signature Zee rings (X-high) since I thought that the reticle might be floating (using too much elevation/windage for zeroing) and caused the problem (i.e., not optically centered). This is not the cause.
3) Checked the possibility of clipping by painting white marker on the baffle inside the shroud. There was no evidence of clipping.
4) Sorted the pellets (JSB heavy, 18.1 grain) based on the head diameters. The POI did change with different head sizes. The smaller head size shifts the POI down and left and to up and right with larger head size. So, this may be pellet related issue. I found the pellet size is not consistent (5.45 mm to 5.56 mm) in the batch of pallets I used. I have 12 tins of this batch of pellets… sad. I still have an old tin with 5.52 and 5.53 mm size (more consistent size) and it groups much better. What is going on JSB?
5) Found the gun lost speed by 30 fps. Adjusted the HST screw to bring back the velocity to 890 fps. Cleaned the barrel really well (almost spotless). Ordered new pallets (around 5.50-5.51 mm head size in this batch). The gun groups well with sub 0.5” (0.35±0.09”) at 50 yds. The POI change is significantly reduced (with occasional flyers).
6) The barrel cleaning shifted the POI by 3-4 clicks on both elevation and windage in my Hawke 4030. It gradually moved back to the original zero after ~200 shots.
This is a long journey. The stock Edgun is quite accurate but I think it can be better by tuning the regulator, speed and trigger to your need if the pellets (and my finger) are cooperative. Hopefully, this info is helpful to some of you who have experienced a shift of POI in your Edgun, but the cause of yours might be different from mine.
Have a great hunting season!
Regards,
Endo
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Endo,
I went last night training.. and results where shit. Why?
I don’t know. It was around 10°C in the bunker, quit cold. Is it because of that?
Because I was wearing a jacket against the cold? Me not concentrated enough? Barrel not clean -> cleaned and same results.
Scope was loose? -> checked and was not the issue
Parralax wrong? -> Not the case
Started clipping? -> Cannot investigate because of I can’t remove the shroud!
So, let it be.. maybe a bad day, next week new session.
BUT, i hope it has nothing to do with the cold……….
And, I want new pellets.. I want that AA’s shoot as good or better then JSB’s.. because they are sooooooo ugly..