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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Same setup, another string.
I’ve learn 2 things from this string. The regulator DOES need time to settle. How many shots, I’m not sure, but once it does, it manages air consumption a lot better.
A pretty steady fall in velocity. I will increase HST 1/4 of a turn and make a new string which will be the last for today because it’s getting late.
I wish OG would share his opinion, or better yet, share his new .25 tuning process.
This is after 1/4 clockwise turn on the regulator. The first 20 shots were erratic. Maybe the regulator is settling with the new setup. I just don’t know how to adjust further. The 70th shot was at 105BAR.
I’ll make another string with this setup just to see what happens. First tin of Kings is gone…
Don’t sand it down yet. I put 1-2 pieces of X-ray film, about 1″long, and 1/2″ wide, between the tank and the barrel, inside the ring that holds the tank. The tank and barrel are now parallel but I didn’t confirmed yet that it’s a good mod because I’m afraid that forcing the 2 apart will not seal properly in the brass ring area. More to come.
Tedd, your thought is more convincing. How do you reshape the in lead? Any video? Hopefully, you catch “Flash” tomorrow and get your gun. Don’t oversleep.
Didn’t have a chance to shoot today. My index finger is really itchy.
Dvdrw, you just confirmed Tedd’s pellet/barrel issue. Thank you.
Is this a new mod showing the “reshape” of metal o-ring to solve barrel-tube touching? I though it should be sanded down.:roll:
How’s the new string look like? I bet it would improve a lot by turning down the reg. Please keep us informed.
Endo
Well, there’s your problem :
I really don’t know how the ring got like this. I seat it well and I mount the barrel carefully. I’ll try and fix it .
Later edit: I rounded the ring and flatten it on a plane surface and I got back to 909. I don’t know how long it will hold but the paper sheet on the breech didn’t move during the shot. I shot just once as it’s 20:30 here and my kid and neighbors are sleeping. I just had to shot once so I can go to sleep in peace. More to come tomorrow. But first, a mail to Ed for 5 brass rings order 😀
Well, this sucks. I adjusted the regulator clockwise 1/4 of a turn and left HST as it was. Refiled to 200BAR and the first 3 shots were 423 439 421 😯
I screwed up somewhere and I don’t know how. I’ll take down the regulator to see the position I left it, and what can I do to fix this.
Ed feel free to help if you know what’s going on.
Now we start getting into the area of how pellet head size effects accuracy……..? Anyone know how to go about getting one of those fancy head sizing instruments.
The extra effort to push it in doesn’t bother me at all. Tight is better than loose in this case and a couple others I can think of………
Here it is olgoat:
In the mean time I de-gased the gun but I ruined my hexagon key on the tanks screws. Off I go to buy a Vanadium set.
If only I could de-gas the damn thing. Boy, the .22 was fairly easy to press the valve, but the valve in the .25 is a monster.
In the mean time I filed the plate for the ball bearing and also discovered the barrel touching the tank mod.
I wanted to file the brass oring but found something easier. When I’ll reassemble the gun I’ll see if it works. Now back to de-gasing.
Endo, to me anyway, that string looks like you need to turn the reg down a little and use more HST. The higher HST will flatten out the first 50 shots and you shouldn’t have the big speed increase after the gun comes off of the reg. That is what I would do IF the gun had the old air valve.
The new air valve might be changing the whole ball of wax when it comes to tuning a Matador! I hope that after I track my UPS driver down tomorrow my 25 standard shoots in the 885 range and gives me 60 regulated shots while doing so. If it does, I can just sit back and be happy that I don’t have to tune it! Hey Wait! 😯
Endo, Dvdrw, JDR and Gabe, I didn’t think that the probe O rings were causing the bolt to be hard to push in for the last ½” when loading a JSB pellet. Both of my 25 Matadors took a lot more effort to seat the pellet than my 22 Matadors take. I think that the extra force is a combination of the 25 cal JSB having an over size head/skirt to bore dia compared to the 22 head/skirt bore dia. AND:
I also think that LW doesn’t put the right taper on the in lead on their 25 cal barrels. I had the same problem on both of my 25 long Matadors. I reshaped the in lead and crown on both of them and then polished the reshaping. I can’t leave air gun stuff alone, I have to modify it. I have bought 5 barrels from LW and they all needed the in lead and crown redone also.
After reshaping and polishing the in lead, the probe will seat the pellet like it was made out of butter. There is a night and day difference in the before and after pellet seating! It is one of the modifications, like rounding off the square edge on cocking probe plate that, doesn’t really need to be done but, I really like the “snick” that the bolt makes as it easily seats a pellet and then rotates down.
If my 25 standard shoots in the 880-890 range, I will leave the reg alone but, I will redo the in lead and crown because I just can’t leave Matador stuff alone!
I can’t say that reshaping the in lead produced any increase in accuracy. The first times shooting either of my 25s at the range were on a breezy day and I didn’t get very good groups. I did the barrel mods before I went back.
Guys; if you think that I am full of shit about redoing the in lead, how about a little show and tell here. Seat a pellet, remove the barrel and push the pellet back out of the breech end of the barrel, take a pic and post it here. I am willing to bet money that the pics will show that the stock LW barrel will leave a lead ‘tail” where it has been forced into the bore. A reshaped in lead followed by polishing reduces the tails.
Here is the only pic that I could find of the before and after reshaping and polishing on my R3 25 long. Left is before, center is after and right is the JSB in the BSA barrel before the BSA barrel got the reshaping and polishing.
endothelium,
It seems that your reg is set exactly like mine. If you increase the HST 1/4 of a turn so you can start around 890, you will have the same string as I do.
In your graph, if your string would of started with 890 and developed the bell curve towards the last third of the string, that would suggest decreasing the regulator, but in our settings, I can only see an increase of the regulator to resolve our problem. If I’m wrong I will go the other way and post my results in a few hours. My plan is at least 60 regulated shots at around 890 with maximum 15 fps ES.
I think with a different diameter pellet you may find it is easier to load. I know in my USFT the CPH pellets are far harder to load than the JSB pellets…
Damn computer won’t load PhotoPhucket vids… 😡
Two more days!!! 😀
Synopsys, I don’t think this is it because I have to push the bolt really hard to load the pellet, once it is loaded, then the bolt probe moves freely in and out. This only happens during loading the pellet into the breech. Without pellet, the bolt also move freely (effortless) in and out from the breech.
Mrnewbie, my 22 does not behave like this at all. It is as smooth as silk when loading the pellet, including CPH. There is only a slight resistance that you can feel when the o-rings plug into the end of the breech. As Ed described “they touch it for few last mm. of the movement.” It is a nice feeling as you described – sense of security of a complete pellet loading. I am not saying this is a “problem” as I put a quotation in there. I just don’t know why it is so hard to load the pellet in my 25 in the last 0.5″ push. If you have seen Jdr’s video, I have to double his effort to load the pellet in my gun.
Endo
Send it to me. I can sort out that regulator! 🙂
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Have you fellas not seen what a good regulator string looks like?
Confused over here!