FX FX Impact M4 - Velocity consistency?
- Thread starter Xcaliber
- Start date
It's true.,...lol Absolutely love my Notos, it's my backyard pesting workhorse, this little gem simply works every single time without fail. it doesn't even need tuning, absolutely zero dramas! lol Only thing i did to it is a couple of 15rd magazines and a moderator insert for like $40 to make it mouse fart quiet.
Same goes for my Avenge-X, it has been consistent and predictable, zero problems or dramas from it, only dislike is the super long footprint at well over 4ft long, nowhere near as agile as the Notos and M4 though.
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That does help a lot. What I did with my m3 when I had it. I had the tune sweet spotted at like 13 on the wheel so I could put it on 16 when it was a cold gun. Cut that early shot fps deviation down a lot.
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Oh wow is me, wow is me!
I cannot properly and correctly tune or accurately shoot my M4 like Mr. Adam Migel.
I look in the mirror and see perfection created in the image of the God in which we trust ..... so it cannot be me.... it has to be that spawn of Satan M4.
I cannot properly and correctly tune or accurately shoot my M4 like Mr. Adam Migel.
I look in the mirror and see perfection created in the image of the God in which we trust ..... so it cannot be me.... it has to be that spawn of Satan M4.
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No not because there is a leakage on the reg side. If there is a leakage and pressure drop on the reg side. The pressure side will only fill the gap to achieve the same equilibrium.
BUT temperatures can change. Just after the plenum or regside fills with new air it will be cold because of the pressure drop.
The air will expand when getting warmer acc.to pV=nRT "Ideal gas law"
V,n,R are konstant so the pressure will increase with
Temperature change in Celsius / Plenum Volume
T/V
There could be other reasons for the first shoot to be slightly different. Like friction in hammer pin, Friction in the barrel, and orings due to grease setting etc.
I have no idea how much this plays. But you cant loose pressure in just the reg side like you described.
But the pressure can increase in the regside because it cannot go back in to the bottle
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i came across a thread when i was researching this subject last night and decided to re-tune my new M4.
www.airgunnation.com
I've tested a few combination of settings, I ended up dropping the reg down to 70 bar, increased the Macro wheel to 6, opened up the valve to about 4.5 line , and able to maintain the same velocity as the default 100 bar reg, Macro 3, and Valve line 4. After leaving the gun overnight, the discrepancy from the first few shots seems to be so much better now.
This is the first magazine run of the day, much tighter spread and first 2 shots isn't too far off from where i had it tuned. Usually i would get 890 to 900fps in the first few shots after the gun sat overnight before it normalized back to around 950fps, the new tune seems to have mitigated the slow first shot symptom, i think it would get a bit better after a few more mags for the valve, HS, and reg to stabilize more. Here's the ProChrono DLX Chronograph reading:
Can't speak for the older M3 or someone else but at least in my case with this new M4, the slow first few shots seems to had been tuning related, the stock tune is no bueno. I would re-tune again if and when i need to up the power to propel much heavier slugs to find the balance again.
Tuning - Frustration With the FX Impact M3
Just got my M3 back from getting its valve replaced. It started leaking through the transfer port after a shot and I figured the bad valve is why I had very inconsistent shot strings. Got it back from Utah Air (which they did a great job of quickly repairing for me) and go to shoot .25 mk1...
www.airgunnation.com I've tested a few combination of settings, I ended up dropping the reg down to 70 bar, increased the Macro wheel to 6, opened up the valve to about 4.5 line , and able to maintain the same velocity as the default 100 bar reg, Macro 3, and Valve line 4. After leaving the gun overnight, the discrepancy from the first few shots seems to be so much better now.
This is the first magazine run of the day, much tighter spread and first 2 shots isn't too far off from where i had it tuned. Usually i would get 890 to 900fps in the first few shots after the gun sat overnight before it normalized back to around 950fps, the new tune seems to have mitigated the slow first shot symptom, i think it would get a bit better after a few more mags for the valve, HS, and reg to stabilize more. Here's the ProChrono DLX Chronograph reading:
Can't speak for the older M3 or someone else but at least in my case with this new M4, the slow first few shots seems to had been tuning related, the stock tune is no bueno. I would re-tune again if and when i need to up the power to propel much heavier slugs to find the balance again.
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I'm not sure, going to have to tune it for higher reg pressure for slugs to see if i could replicate the same issue, 70 bar certainly is not enough to drive the AEA 25gr i just received today, the tune is mainly for 18gr and below.
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I’m curious about something. The next time your gun is at 90b in the tank, do another shot string until you hit your 70b reg setting. We can run what I call full throttle tunes with our M3’s because we have two regs. I would like to see if a M4 can do it. When I tried it with my single reg MKll’s, the guns only shot slugs well in a certain pressure window. Another thing you’ll need to know. If you are going to use your valve knob to trick the valve lift into thinking you’re using less hammer spring tension, keep an eye on the rubber balls in the valve knob. As you smash them flat, things change. Velocity goes up. If you are doing an extended shooting session and notice your velocity rising, you are abusing those rubber balls. Not good.
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Sure, you mean when the bottle pressure get down to 90 bar, record the shot string run down to 70 bar? to see what the velocity look like within that 20 bar range before it drop off of the reg?
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This is the shot string, things seems to stabilized a lot more after it burned through about 7 mags worth of pellets since this afternoon, getting tighter ES and SD, which isn't too shabby. I get 1 mag worth of shots going from 90 bar down to 70 bar on this 480cc stock bottle, velocity looks stable, nothing look out of the norm other than i'm running it a bit hot with an average of 941 fps with these CPHP pellets, pretty much the cheapie stuff for breaking in and stabilize the tuning.
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Another tiny educational tip: The micro HST value is the one to reference and document. The macro simply jogs the micro by several clicks, serving to allow presets for different speeds/ammo for fast and repeatable switching.
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Your average speed when your bottle is full is 960fps. Your average speed when your bottle is not in its upper range is 940fps. That might not work when you switch to slugs. A 20fps swing is a decent harmonic swing. I just noticed your posting about your macro. Macro is irrelevant, the micro is the one you need to keep track of for your notes.
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Impact M4 is more for competitive shooters, not for hunters.....there I said it....this is why they don't care to fix it because the valve break away friction is fault of a design that benefits competitive shooting.
There is NO part to 100% completely fix this due to the nature of balanced valves for the entire slope of the tune, only mitigation or a non-balanced valve. Period.
-Matt
There is NO part to 100% completely fix this due to the nature of balanced valves for the entire slope of the tune, only mitigation or a non-balanced valve. Period.
-Matt
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Micro at 2 1/4 when Macro at 6, it's at 2.5 when Macro moved to 8.
CPHP seems to fly better between 890 to 900 so i'll dial it down further to get it closer to 900. The Macro wheel allows me to jack up the power quicker when i load heavier pellets going from 14gr to 15.8 or 18gr, i leave the micro wheel alone when the macro one gave me what i needed, and will adjust the micro one on as needed basis.
CPHP seems to fly better between 890 to 900 so i'll dial it down further to get it closer to 900. The Macro wheel allows me to jack up the power quicker when i load heavier pellets going from 14gr to 15.8 or 18gr, i leave the micro wheel alone when the macro one gave me what i needed, and will adjust the micro one on as needed basis.
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I disagreed.
There are many competent hunters who use these Impacts primarily for hunting, be it the SA boys, Utah Airgun crew, or HunterOne Productions dude from youtube who smoke squirrels out to hundred yard. A good hunter will make the tool worked for them, whichever rifle they have access to in their arsenal. They don't seems to be obsessed with chasing after numbers, none of them even care about the "slow first shot" type drama or ever care to mention it, i highly doubt it ever affect what and how they use the impact for, and the impact is just another tool for them. Ultimately that's the only thing matter to a lot of those hunters, whether they get the kill or not. Hunter kills, while Measurebator chase after numbers.
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Any and every hunter concerned with results and ethical hunting cares about the potential for an errant first shot of the day. They may have worked out a solution or workaround for it, but they most definitely care about it.
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That's funny when the SA boys like Matt Dubber is on FX payroll. They're paid to promote those guns. Of course they are going to be using them and heavily edited videos. UA is also heavily involved with FX being the importer and distributor. Those aren't good examples.
As a hunter myself numbers are not what matters, it's where that first cold shot hits after a few days of sitting compared to the rest. Alot of my cold shots are 80yds. It does matter to me.
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