The first shot is faster than average velocity
I currently realized that the first shot is about 893 fps and then go to average 883, 885, 886 fps. Is that meant that some orings need to be replaced? It has shot about 3 or 4k pellets.
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The bobbin has two o-rings to separate high pressure side and low pressure side from the pressureless chamber where the belleville washers reside. This chamber has a vent hole to atmospheric pressure. That is how regulators work. If one or the other o-rings would leak. the gun would loose pressure altogether. When the o-rings on the outside of the reg leak the gun will loose pressure.
When the seal against the white sealing material of the bobbin and the small sharp bumb in the regulator adjustment screw leaks pressure will creep up slowly till enough force acts on that seal to stop the leak.
A valve hammer combination always has a bellcurve and an optimum where a difference of some PSI doesn’t make a large impact on velocity. You just use the reg to cut of that pressure range where you need it.
For instance your valve and hammer have max velocity at 1800PSI and you set your reg to say 2200 PSI you will start to see velocity rise when the system goes off reg. When you set it at say 1750-1700PSI you won’t even notice the gun going off reg for quite some time till the system gets to say 1600PSI. That is in my point of view a well balanced system.
Same goes for a reg set to low. You’ll notice a sharp decline in velocity once the gun goes off reg. Also not the place to be at
In my experience the best place to be is just a tad bit after max velocity.
Here’s a pic with arrows of the bobbin o-rings and seals I mean.
As for poi according to chairgun means not to much to me. Real world experience does. In my unregulated stealth a velocity drop of 5m/s ege 15ft/s does very little to poi at 50 and 100meters. Not enough for me to notice anyway.
Cheers,
Marc
Mark, the 2 O rings that I am talking about are inside the regulator. If either of the 2 O rings on the outside of the regulator housing are leaking, they will bleed out of the regulator vent hole. A leak there would cause the Matador to lose pressure overnight. A leak there wouldn’t cause a figher speed first shot.
A tuned Matador shouldn’t have a higher speed first shot and it won’t have a bell curve.
As far as not being able to see a 10fps difference in POI, Chairgun shows a .325″ POI difference between 880fps and 890fps at 100 yards using JSB 25.4 grain pellets.
Your regulator is bleeding air past it and sending the regulated plenum space with a higher pressure than what the reg set pressure is. One or both of the regulator’s “bobbin” O rings needs to be lubed with silicone grease and/or replacesd.
If I see a higher first shot fps and then a good shot srting, I replace the 2 O rings on the regulator shaft “bobbin”.
You should be able to shoot a Matador that has sat for weeks/months withoout having the first shot being higher than the next shot.
I’m not completely familier with the edgun regulator, but here’s my thought on the matter.
This leackage probably has nothing to do with the o-rings on the bobbin. If that were the case your regulator would leak through the regulator bleed hole(the part that is between the 2 o-rings). It’s most likely the seal between bobbin and the part it has to seal against at the end of it’s travel. A little leackage is not uncommen. You probably won’t even notice the 10ft/s on your POI. What it does show is that the working range of your valve/hammer setup isn’t matched to the regulator set pressure. A valve/hammer setup give you a bellcurve where a bit more or less pressure won’t impact the velocity so much. The middle of that range is where you wan’t to be with your reg pressure.
Brother Charlie,
Please post the results & let us see the differences, ,,,,,
Thank you all. I just ordered oring kit from Ernest. I’ll replace some orings and ajust reg. to 1530 psi and try again.
The first shot should not have a higher speed over the next shots.
Your regulator is bleeding air past it and sending the regulated plenum space with a higher pressure than what the reg set pressure is. One or both of the regulator’s “bobbin” O rings needs to be lubed with silicone grease and/or replacesd.
If I see a higher first shot fps and then a good shot srting, I replace the 2 O rings on the regulator shaft “bobbin”.
You should be able to shoot a Matador that has sat for weeks/months withoout having the first shot being higher than the next shot.
yes, just the first shot is different. The most of them are all good, from 882 to 886 and get about 86 shots per fill.
I’d like to know if other r3m owners have the same situation.
I forgot to put this in R3M thread.
Brother Charlie,,,,
how about the rest of the shot counts ,,,velocity? are they near from each other ? is your string is nice and only your 1st shot is faster!!? if yes,,,then what is wrong with that??!! you can don’t aim your 1st shot toward the target ,,,make a dry fire or shot to the safe place and keep going …. for the rest ,,,
how many shots will you get now?
i was surprised when you told me that i have a STD edgun and getting a 80 shots for an average of 885 fps ,,,, that is really really awesome,,, if still your gun is performing like this ,,,just don’t touch it … it is very good …
It usually takes overnight. The first shot is faster. Is that normal? or need to replace orings?
I think that depends on how long its been since it was shot last time. I think the manual says that a little seepage is normal and thwt it should be shot every week or something like that. I’m sure someone can chime in as to how long is acceptable. However, I would think u would see a much higher fps on first shot if u were getting a full 210 bar at the valve.
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Hi Hemn,
I’ll post the result after I replace the orings and set the reg. to 1530 psi (from Ernest’s posts, this is the best pressure to set).
I”ve never lube the orings(inside the reg.) since I got it, I did on 2 orings outside reg.
Brother Charlie,
Please post the results & let us see the differences, ,,,,,