FX FX Impact M4 - Velocity consistency?

[Xcaliber]

Just curious, when you left your FX Impact M4 overnight and shoot it the next day, the very first shot you took in the follow day does the velocity changed from the previous day?


If there's no change in velocity no matter how long the gun left unused, then it should indicate everything is working as it should.

If it's lower in the first couple of shots, then went back to the same velocity as previous day, then it could possibly mean there's a small slow leak in the plenum or the reg right?

If it's higher in the first or 2nd shot the next day, then drop back down to the same velocity as previous day, then that's possibly a sign of reg creep, when more air creeping into the plenum overnight


Not taking about POI or anything, just the velocity alone.

 

[2fast2furious]

It's something all fx impact does. It's called reg creep. Some will be very little. Some will be big. But all impacts I know does it. Even after a rebuild or even buying a new reg it will happen. Why is first shot slower? Cause over night or after few hours, reg creep cause plenum to be higher. You think higher pp means more power but no. The hammer doesn't have enough strength to hit the valve. That's why fps is slower. After 1-2 shots, it goes back to normal. This is normal on an impact. But not normal on other guns. I own an marauder rifle, prod, avenger, notos. After over night, they still shoot about the same speed as before. I believe only the impact does it cause the reg is very small to handle regulating that much pressure.

 

[Xcaliber]

It's something all fx impact does. It's called reg creep. Some will be very little. Some will be big. But all impacts I know does it. Even after a rebuild or even buying a new reg it will happen. Why is first shot slower? Cause over night or after few hours, reg creep cause plenum to be higher. You think higher pp means more power but no. The hammer doesn't have enough strength to hit the valve. That's why fps is slower. After 1-2 shots, it goes back to normal. This is normal on an impact. But not normal on other guns. I own an marauder rifle, prod, avenger, notos. After over night, they still shoot about the same speed as before. I believe only the impact does it cause the reg is very small to handle regulating that much pressure.

interesting..... could the effect be minimized when the reg is set closer to the fill pressure? say....reg at 160 bar, and only fill the bottle to 200 bar, with only 40 bar of pressure differential....would it still creep?

if the hammer is being set close to the max, then it should have more strength to hit the valve when the plenum has higher pp (due to reg creep) after sitting overnight, and that in theory should reverse the lower fps and end up getting higher velocity in first shot, right? So it sounds like having higher HS with lower reg pressure instead of the other way around maybe could at least minimize the velocity discrepancy in the first few shots after sitting overnight.

 

[2fast2furious]

interesting..... could the effect be minimized when the reg is set closer to the fill pressure? say....reg at 160 bar, and only fill the bottle to 200 bar, with only 40 bar of pressure differential....would it still creep?

if the hammer is being set close to the max, then it should have more strength to hit the valve when the plenum has higher pp (due to reg creep) after sitting overnight, and that in theory should reverse the lower fps and end up getting higher velocity in first shot, right? So it sounds like having higher HS with lower reg pressure instead of the other way around maybe could at least minimize the velocity discrepancy in the first few shots after sitting overnight.

I have not tested my impact to reg 160 and fill to 200. But would seem to minimize the spread imo. I tested my reg from 110 to 150 bar, but I always fill to 250 bar. So first 1-2 shots are always lower. As for 160bar reg, even power wheel on max wouldn't be able to be enough. Would need a heavy hammer weight. But you do not want to over power the hammer for the reg pressure. Example if your reg is set to 120 bar, you do not want to over power it by setting to power 16 on wheel. You are wasting air and it wouldn't be a good tune. You want your reg and hammer to match. From my experience, you set reg to whatever you want, and keep turning power wheel up each shot until fps no longer goes up. Then back off a turn.

 

[Xcaliber]

I have not tested my impact to reg 160 and fill to 200. But would seem to minimize the spread imo. I tested my reg from 110 to 150 bar, but I always fill to 250 bar. So first 1-2 shots are always lower. As for 160bar reg, even power wheel on max wouldn't be able to be enough. Would need a heavy hammer weight. But you do not want to over power the hammer for the reg pressure. Example if your reg is set to 120 bar, you do not want to over power it by setting to power 16 on wheel. You are wasting air and it wouldn't be a good tune. You want your reg and hammer to match. From my experience, you set reg to whatever you want, and keep turning power wheel up each shot until fps no longer goes up. Then back off a turn.

Makes sense, the lower velocity in the first 2 shots doesn't affect the POI or anything, just seemed a bit odd until you pointed out it was the HS didn't hit the valve hard enough that causes lower velocity in first shot or two, before it went back to normal. lol

 

[Airgunmann]

Oring stiction doesn't help either inside the plenum and then to top it off if the reg creeps it doesn't help

 

[Vetmx]

There was a giant topic about this problem with the FX Impact. And no, FX didn’t fix it with the M4. But a lot of us addressed it with our personal guns. I don’t feel like finding the topic but you can search slow first shots Impact.

 

[weevil]

Makes sense, the lower velocity in the first 2 shots doesn't affect the POI or anything, just seemed a bit odd until you pointed out it was the HS didn't hit the valve hard enough that causes lower velocity in first shot or two, before it went back to normal. lol

A lower velocity always affects the poi. You may not notice it if you’re shooting at short range. Read up on near and far zero for more insight. As others have mentioned, this is more a function of valve stiction than creep. I sold my M3 for this reason. It couldn’t be relied on to hit the mark on a cold shot. Rats at 80 yards were chuckling when it was pointed at them. The higher the reg pressure, the worse it got. Didn’t notice it so much with a mild pellet tune.

Once warmed up it was great. It went to live with a paper puncher who loves it.

 

[Xcaliber]

Damn, the impact is already on 4th generation, and FX still haven't figure out how to prevent the valve stiction and reg creep shenanigans after all these years? I'm diving deep into the search and reading up on them.

What have FX been doing all these years? and where did they invest their profits on if not on R&D? Are you sure these are made in Sweden and not from Nigeria? Even the made in China cheap Snowpeak and other low budget guns don't have these issues.....

 

[weevil]

I was really hoping for a fix with the M4 through addition of the Dynamic/Panthera valve. There were many things I loved about the M3. I’m still waiting to hear if the M4 actually has the stiction issue. Haven’t seen anything definitive.

 

[FastPellet212]

The first low shot is easy to overcome. Just put a couple clicks on the power wheel and there you go. Lol

 

[2fast2furious]

Makes sense, the lower velocity in the first 2 shots doesn't affect the POI or anything, just seemed a bit odd until you pointed out it was the HS didn't hit the valve hard enough that causes lower velocity in first shot or two, before it went back to normal. lol

Mine is off by about 50-60 fps from first shots to when it normal with what I set to. It may not affect POI if you are shooting close distance you will not notice the difference. But if you shoot further out, say 100 yards. 50-60 fps difference can be a hit or miss.

 

[Vetmx]

Damn, the impact is already on 4th generation, and FX still haven't figure out how to prevent the valve stiction and reg creep shenanigans after all these years? I'm diving deep into the search and reading up on them.

What have FX been doing all these years? and where did they invest their profits on if not on R&D? Are you sure these are made in Sweden and not from Nigeria? Even the made in China cheap Snowpeak and other low budget guns don't have these issues.....

If you don’t hunt with the gun in situations where you can keep it warmed up, it’s a big deal. But I believe the majority of Impact owners dating back to the MKl are accustomed to shooting dirt or “checking their zero” before they get down to business shooting. I also believe that FX knows this so why should they reinvent a critical part of the gun just to appease a small percentage of owners. They also are aware of that topic and the two ways we made our guns better. Notice I didn’t say completely fixed. If they address it, they admit that the boatload of MKll’s, M3’s and M4’s are flawed. Notice I didn’t say MKl. That gun had plenty of other issues. But wasn’t bad on first shot velocity. Not perfect, but better than its descendants.

 

[Xcaliber]

Mine is off by about 50-60 fps from first shots to when it normal with what I set to. It may not affect POI if you are shooting close distance you will not notice the difference. But if you shoot further out, say 100 yards. 50-60 fps difference can be a hit or miss.

yea i didn't notice any difference below 50 yards, but that sounds about right. lol

If you don’t hunt with the gun in situations where you can keep it warmed up, it’s a big deal. But I believe the majority of Impact owners dating back to the MKl are accustomed to shooting dirt or “checking their zero” before they get down to business shooting. I also believe that FX knows this so why should they reinvent a critical part of the gun just to appease a small percentage of owners. They also are aware of that topic and the two ways we made our guns better. Notice I didn’t say completely fixed. If they address it, they admit that the boatload of MKll’s, M3’s and M4’s are flawed. Notice I didn’t say MKl. That gun had plenty of other issues. But wasn’t bad on first shot velocity. Not perfect, but better than its descendants.

I can imagine it's not very convenient when the hunter couldn't (or simply didn't want to) run a pre-check prior, it can be irritating to some people for sure.

 

[FastPellet212]

yea i didn't notice any difference below 50 yards, but that sounds about right. lol



I can imagine it's not very convenient when the hunter couldn't (or simply didn't want to) run a pre-check prior, it can be irritating to some people for sure.

I’ve killed so many pigeons at 100+ yards without taking a few shots with my M3. I’m serious, just put a couple clicks on the power wheel. The issue has been widely overblown over the years.

 

[Xcaliber]

I’ve killed so many pigeons at 100+ yards without taking a few shots with my M3. I’m serious, just put a clicks on the power wheel. The issue has been widely overblown over the years.

It didn't create any issues for me, the M4 has everything i need and love about it, if it bothers me enough in the future then i'll put a few clicks up on the power wheel for the first 2 shots, or better yet...simply dry fire 2 shots, i don't store my PCP with mag in them anyway, always take it out and make sure it's unloaded when i put it away, no big deal.....otherwise i'll just leave it be.

 

[Vetmx]

It didn't create any issues for me, the M4 has everything i need and love about it, if it bothers me enough in the future then i'll put a few clicks up on the power wheel for the first 2 shots, or better yet...simply dry fire 2 shots, i don't store my PCP with mag in them anyway, always take it out and make sure it's unloaded when i put it away, no big deal.....otherwise i'll just leave it be.

And that’s why FX hasn’t fixed it.

 

[Xcaliber]

And that’s why FX hasn’t fixed it.

They still should though, found the 22 page thread from two years ago, it's definitely an annoyance to a lot of people

Tuning - FX Impact Mk2/M3 - slower first shot - no reg creep - quasi-scientific analysis

Hi guys, Welcome everybody. This is my first post here. I have a problem with my Impact Mk2 PP .30. The reg pressure is 145 bars. When I shoot shot after shot then my v0 is 260m/s. However, when the gun sits for a couple of hours then the first shot is 250m/s despite the exact same reg...

www.airgunnation.com

Unfortunately the valve stiction and reg creep issues aren't unique to the impact, i saw on that thread someone mentioned the same symptiom from wildcat, maverick, even from other brands beside FX.

 

[Dairyboy]

And that’s why FX hasn’t fixed it.

And why some of us simple won't own one. But we're haters if we say that lol

 

[Vetmx]

And why some of us simple won't own one. But we're haters if we say that lol

Come on. Don’t you want to sneak around the farm clicking your hammer spring up depending on how long it’s been since your last shot? You don’t know what you’re missing. Seriously though, besides that issue I think you would enjoy a compact with a light scope and no weight gaining accessories. The little 500m can be handled pretty rough and hold its zero. But like some of your other guns, I think you wouldn’t have it long. It would eventually make you mad about something. It’s what they do. But you learn a lot.