FX How to get higher velocity??

[PCPGUY]

I have original impact and just installed the 750 power plenum and power block. I can’t get higher than between 850-860 for some reason. I dropped reg down to 100 maxed hammer spring all the way, knob and fine adjuster and have the air flow to line 4. If I try to increase reg pressure fps drops. Am I doing something wrong here?

 

[ChuckHunter]

Most likely need a heavier hammer and spring! Not enough to open the valve at higher pressure's.

 

[6gun]

Hammer to handle more reg pressure. What caliber and what weight projectile? What length barrel(just my curiosity)

 

[PCPGUY]

Hammer to handle more reg pressure. What caliber and what weight projectile? What length barrel(just my curiosity)

.30 shooting 44.75 atomic and 600mm barrel. I guess I’ll order heavier hammer and see. Go with tungsten or huma?

 

[greenbeans]

.30 shooting 44.75 atomic and 600mm barrel. I guess I’ll order heavier hammer and see. Go with tungsten or huma?

Huma. Tungsten is for very high pressure, like 150-160b. Otherwise your just smacking your valve to bits.

 

[PCPGUY]

Huma. Tungsten is for very high pressure, like 150-160b. Otherwise your just smacking your valve to bits.

any specific weight?

 

[delooper]

I think the other answers are more to your point. But in general if you want higher velocities you want a longer barrel and/or more air pressure and/or lighter projectiles. Depending on your current setup one might be more relevant than another, for example if you don't have enough air pressure, extra barrel length won't do anything for you.

 

[greenbeans]

No idea tbh, depends on what pressure/speed your target is I guess. To be honest sounds odd that you’re valve locked at 100bar but based on speed dropping with more reg it seems like it… I’d get the huma set with the two weights. Also make sure that the internal hammer adjuster screw is safe at home.

 

[PCPGUY]

No idea tbh, depends on what pressure/speed your target is I guess. To be honest sounds odd that you’re valve locked at 100bar but based on speed dropping with more reg it seems like it… I’d get the huma set with the two weights. Also make sure that the internal hammer adjuster screw is safe at home.

What do you mean by the internal screw?

 

[JimD]

I would first go back to the settings you used before you made the changes (regulator and hammer spring). Just adding the bigger plenum should add fps with no other changes. I presume the power block means bigger internal passages and those two would add fps with no other changes. If that does not happen, I would try lowering the hammer spring force. It seems a bit counter intuitive but either two much or too little hammer spring force can lower your velocity. Sometimes less is more. Once you see a logical impact of your changes (maybe 100 fps more than before?) then if that is not enough, you would increase the regulator and the hammer spring and find the right balance (usually 3-5% below the peak velocity for that regulator setting). If your velocity is low with an increase in the regulator and with the hammer spring as high as it can go, then and only then I would go to a heavier hammer.

If you change too many things at the same time it is possible to get lost and just make it more difficult to find a good tune. Adding a hammer change might be a somewhat lucky guess and help but it might also just mess things up more.

 

[ChuckHunter]

I would first go back to the settings you used before you made the changes (regulator and hammer spring). Just adding the bigger plenum should add fps with no other changes. I presume the power block means bigger internal passages and those two would add fps with no other changes. If that does not happen, I would try lowering the hammer spring force. It seems a bit counter intuitive but either two much or too little hammer spring force can lower your velocity. Sometimes less is more. Once you see a logical impact of your changes (maybe 100 fps more than before?) then if that is not enough, you would increase the regulator and the hammer spring and find the right balance (usually 3-5% below the peak velocity for that regulator setting). If your velocity is low with an increase in the regulator and with the hammer spring as high as it can go, then and only then I would go to a heavier hammer.

If you change too many things at the same time it is possible to get lost and just make it more difficult to find a good tune. Adding a hammer change might be a somewhat lucky guess and help but it might also just mess things up more.

It's a first gen impact and .30 cal.
It definitely needs more hammer to go above what he's already getting.

 

[greenbeans]

What do you mean by the internal screw?

The screw holding the indicator for the hammer setting in place. There’s a screw in there that holds it and screws into the actual hammer adjuster. If it’s loose you’d probably have noticed but if it is your actually not adjusting anything when moving the micro.

Man… sorry, didn’t realize you’re talking about first gen impact… In my mind we were talking m3/m4. Forget what I said, sorry.

 

[PCPGUY]

Oh okay yeah it’s there and all the way out, I turned clockwise

 

[greenbeans]

It's a first gen impact and .30 cal.
It definitely needs more hammer to go above what he's already getting.

You’re the man… for whatever reason I didn’t realize gen 1…

 

[coastal drifter]

I would start with more reg 130-140 bar and max hammer wheel also has the allen adjustment on the older Impacts. We used to port the trasfer port on the barrel with a Dremel to get more air flow.

 

[PCPGUY]

Figured it out guys! It was my barrel placement. It was not fully seating through the new power block. I had to fine dremel the notch in the transfer port to make it be able to fully seat. Basically the air was not fully being able to make it through the transfer port

 

[Airgun-hobbyist]

Figured it out guys! It was my barrel placement. It was not fully seating through the new power block. I had to fine dremel the notch in the transfer port to make it be able to fully seat. Basically the air was not fully being able to make it through the transfer port

@PCPGUY what are your velocities now? Back five-plus years ago us "First Gen" Impact owner's did a lot of porting and polishing of the transfer port, block, and valve body, added hammer weight, and added plenums of increasing size to get the airflow and hammer strike acceptable to sling heavy lead at decent speeds. All those modifications eventually have made it to the new FX model's. If you search "Gen 2 Impact" and look at the threads from around 2016-2020 you'll see a lot of the work we did.

 

[PCPGUY]

@PCPGUY what are your velocities now? Back five-plus years ago us "First Gen" Impact owner's did a lot of porting and polishing of the transfer port, block, and valve body, added hammer weight, and added plenums of increasing size to get the airflow and hammer strike acceptable to sling heavy lead at decent speeds. All those modifications eventually have made it to the new FX model's. If you search "Gen 2 Impact" and look at the threads from around 2016-2020 you'll see a lot of the work we did.

With the reg around 130 I’m at 900fps with the 44.75s I still have room to go on the hammer spring fine adjustment and valve adjustment so I’m sure I can get to 1000 with all things adjusted up. I was thinking of getting the huma transfer port and pin probe

 

[Airgun-hobbyist]

With the reg around 130 I’m at 900fps with the 44.75s I still have room to go on the hammer spring fine adjustment and valve adjustment so I’m sure I can get to 1000 with all things adjusted up. I was thinking of getting the huma transfer port and pin probe

The split transfer port is good for additional power. The pin style of probe's don't always cycle in ammo well because it allows the back or front of the ammo to shift as it pushes. (Making for inconsistent loading.) A lot of folks didn't have good luck with them, myself included. I ported out the original FX hollow probe to match the brass transfer port and it worked out great, getting more airflow and still seating the ammo squarely into the brass port because of the flat front.