FX .250 42gr H&N only going 700 fps

[Waiker]

Hello there,
First of all nice to be here.
Now the problem.
I was shooting with my FX Impact M3 today.
Trying out the 30gr from H&N in cal .250. Those were not exiting. So i switched back to the 42gr. same caliber.
But what i recognized was that i only was shooting the 42gr with 700fps.
The setup of my gun is:
700mm barrel
Slug powerkit
Tungsten hammer
1:18 STX Superior Liner FX Heavy
Powerblock from factory (was bought with it)
Pinprobe
Also on it is the barrel carbon sleve and the barrel tensioning kit.
The front reg is about 200bar
The rear reg is 165bar ish.

I am doing something wrong with the tune or is 700fps the maximum speed for that caliber in this gun setup

I tried turning out the valve as far as i can. The fps go up to 1000+ but a shoutgun would shot with less spread
Shoud i add a 800mm barrel to the setup. To get an increase in speed and accuracy?

 

[Impact701]

Hello there,
First of all nice to be here.
Now the problem.
I was shooting with my FX Impact M3 today.
Trying out the 30gr from H&N in cal .250. Those were not exiting. So i switched back to the 42gr. same caliber.
But what i recognized was that i only was shooting the 42gr with 700fps.
The setup of my gun is:
700mm barrel
Slug powerkit
Tungsten hammer
1:18 STX Superior Liner FX Heavy
Powerblock from factory (was bought with it)
Pinprobe
Also on it is the barrel carbon sleve and the barrel tensioning kit.
The front reg is about 200bar
The rear reg is 165bar ish.

I am doing something wrong with the tune or is 700fps the maximum speed for that caliber in this gun setup

I tried turning out the valve as far as i can. The fps go up to 1000+ but a shoutgun would shot with less spread
Shoud i add a 800mm barrel to the setup. To get an increase in speed and accuracy?

Sounds like you need some fine tuning.
Please post pictures of your macro, micro and valve adjuster settings

 

[Waiker]

Sounds like you need some fine tuning.
Please post pictures of your macro, micro and valve adjuster settings

Thanks for your reply. I will send the fotos later. And i also have to check if i have the weaker valve return spring built in.

 

[Floridaman2005]

Thanks for your reply. I will send the fotos later. And i also have to check if i have the weaker valve return spring built in.

It sounds like it’s just improperly tuned. If you can get it to 1000 with the valve full open, what exactly are you doing to limit yourself to 700fps? Are you taking it from 1000+ fps down to 700 with the valve adjuster? You need to find a hammer/regulator combination that works and use the valve to trim excess air off the top for a tighter spread. It sounds like your regulators have plenty of power. You’ll need to provide information on what your quick tune is set to (macro/micro wheel)

 

[Waiker]

These r the current settings i am running
cant upload the fotos so
macro is on 16
micro is on 3.6
and valve is at 12.85 mm open

 

[Impact701]

With those settings is your rifle shooting 700fps or 1000fps ?

 

[Waiker]

With those settings is your rifle shooting 700fps or 1000fps ?

700fps

 

[Impact701]

700fps

How far open do you have to open the valve to get 1000fps?

Did you get part 52 set to the correct length when you put in the tungsten hammer weight

The Viking Airgunner has a great video about tuning the M3

 

[Waiker]

Yes the part 52 is correct installed just checkt it.
also just whatched the video you sent i will give it maybe tomorrow a try and see what i get.
thanks for the replies and i will let u know whats going on

 

[bigHUN]

The tungsten hammer - was this your upgrade on 25 cal M3 ?
What is a weight?

 

[Waiker]

The tungsten hammer - was this your upgrade on 25 cal M3 ?
What is a weight?

I bought the 25 cal regularly. i wanted to shoot heavier slugs line the 42gr. So i took the tungsten hammer in the softer spring and the pinprobe

 

[bigHUN]

That tungsten hammer weight, I cannot remember the weight maybe 16 or 18 g, it is back in a box...I tried it as well...I put back the original hammer weight.
The tungsten was designed for 30 and 35 cal heavy projectiles with a combination of what spring.

 

[Waiker]

I dont know the exact weight of the tungsten.
i think for a .25 cal a 42gr slug is pretty heavy.
as far as i know the 42gr slugs from h&n

 

[Waiker]

short update of mine. Just shot again a view rounds after i reassembled my gun. I think the pocket chrony from fx gives me wrong speeds. The shots fired dont feel like below 900fps. So i gonna buy a new one and test it.

The Chrony is set to air power rifles in the settings.

The settings of my gun are now
Macro: 16
Micro: 3.7
Valve: 1,5 turn after line 4

Those settings come from ernest row his youtube video where he sets up a .35cal to 1000fps

I tried those settings out.
So the recoil and the sound of the gun doesnt feel like its below 600fps.
Its pretty accurate for now.
I think i gonna see what a other chrono says.

 

[Impact701]

I have the tungsten hammer weight in my M3. With the reg at 165 bar with stock hammer weight, you would have the hammer spring tension almost maxed out.

Keep the tungsten hammer weight.

With the valve adjuster 1.5 past the 4th line you are probably wasting some air.

When you get your new chronograph, you can fine tune that adjustment.

 

[Impact701]

The goal is to get the smallest burst of high pressure air, to achieve the best velocity and accuracy.

The tungsten hammer weight allows you to do this without excessive hammer spring tension.

 

[Waiker]

I turned the rear reg back to 150bar. I will keep the tungsten hammer in. Cause i think those heavy slugs with 42gr need it. Sure i also think i am waisting air, but this is a story for the new chrony i just orderd.

I also read something about the FX Pocket Chronograph. My thoughts about it are those: Maybe the FX Pocket divides the real velocity of my slug by 2 or something. my thoughts behind the divinding is, if there are built in 2 radar units and one dies so only one is measuring would it divide the real velocity by 2.

that would explain why the velocity mesured of the chrony is below 600. what i didnt do today was to
change the velocity on my FX App. so i can see where the velocity is.

As said the gun and the air that pushes the slug down the barrel and leaves it doesnt sound like below 600fps.
when i turn out the valve adjuster as far as i can the FX shows 700fps but when you shoot you defenetly hear the crack when the slug goes past the speed of sound

i measured my Walter Dominator back in the days the velocity i remember was 600-700fps. and the sounding and recoil was diffrent to the fx now.

but the real result will show the new chrony i orderd

 

[Waiker]

The goal is to get the smallest burst of high pressure air, to achieve the best velocity and accuracy.

The tungsten hammer weight allows you to do this with excessive hammer spring tension.

yes true. as i know the the hammer and the reg should be in harmony to each other. the valve adjuster is just to close the valve when the slug exits the barrel so there are no turbulences behind the slug.
as far as i know the tungsten is just the handle higher reg pressure easier then the standard one.

correct me if i am wrong

 

[Waiker]

So now i know a lot more. The fault is not the chrony or so. Its zhe barrel itself. I just measured the walter dominator where i knew its shooting at about 700fps. And it shoots at 700fps as my chrony said.
So now the fault could be the barrel.

Edit:
Checked my o-rings they r fine
Shooting again with those settings
Macro: 16
Micro: 3.7
Valve: 1,5 turn after line 4
Again i am under 700fps
Switched the liner from the 1:18 to the standard liner
Again under 700fps
Can the oring in the dual transferport be the problem?

 

[Pysiths]

What tranfer port are you using, slug or pellet marked on the barrel assembly. Check your probe and projectile for alignment \ cleance of the transfer port. I had my probe in my slug kit move causing the pellet/slug to partially cover the tranfer port.