• The AGN App is ready! Search "Airgun Nation" in your App store. To compliment this new tech we've assigned the "Threads" Feed & "Dark" Mode. To revert back click HERE.

Tuning FX Impact M3 Dwell time and accuracy or do I just Stink ?

Jump to latest Follow Reply
E

E_Welch

Member
Dec 31, 2021
58
2
PA, United States
Hello everyone , here in PA it has been pretty chilly so I haven't done much shooting my FX Impact M3 compact in .22 outdoors. However I have spent some considerable time with it indoors shooting into a pellet trap and playing with and learning the system and tuning . 

I recently started shooting the JSB .22cal 18 grain pellets and after some time I have really been able to get my spread and standard deviation into what I consider a really good place .Over a 28 shot string I am somewhere around a spread of 5 and an STD of less than 2, normally around 1.5 (this is the best I've been able to achieve) 

Well it finally got above freezing today and the sun came out for a bit so I went out to see how its grouping . To my disappointment my groups are worse than when I wasn't worried about any of the numbers(shooting @50 yards) .It got me thinking , in my attempt to chase the numbers I turned the second regulator pressure way down , from 110-ish to around 85 . To achieve the same FPS (shooting for around 860) I in turned turned the micro adjuster up from below 2 to around 3 . I am new to airguns and come from powder burners where dwell time is very different. 

Finally to my question , am I that bad of a shot ? Or has lowering the regulator pressure and increasing the micro adjuster increased my dwell time and while not actually effecting the accuracy of the gun has made the gun "harder" to shoot accurately? 

I'm going to spend some time over the next couple of days tuning back with a higher regulator pressure and a lower micro adjuster setting and see what effect it has. However I'm not sure when ill be able to shoot outdoors again so I figured I would ask for some guidance from you all here . 

Side note : If anyone has a heated warehouse in PA where we can shoot 50 yards or more I'm not above paying for the privilege lol 




 
You’re just wasting lead chasing those numbers in your house. What you can do is open the valve all the way then follow the proper procedure for finding a good second reg setting. You want to wind up around 900fps when you back the hammer wheel down to the knee of whatever reg setting you found that gave you around 930fps maximum speed. Then you can go outside and test accuracy. Maybe turn the valve in a little at a time to see if it tightens your groups. The valve adjustment is what changes dwell. Dwell is how long your valve is open. Once the gun is shooting great, then you concern yourself with ES and SD numbers if you feel it’s necessary. If you don’t understand any of what I wrote then it’s time to put the gun in its case and do some research and reading. 
 
Upvote 0
85 is pretty low and 18 is a pretty light pellet right? Before getting too frustrated I’d try increasing both.


Heated warehouse ? I live in Shippensburg and between the MD border and Harrisburg there should be a distribution center that would work. Gotta be hundreds along the 81 corridor.
Click to expand...

85 is pretty low but I am pushing the 18 grain pellets at about 875 FPS on average which from what I've seen and read should be a good speed for a diablo shaped pellet . I am going to mess with turning the regulator pressure up and see what effect that has. 

I live in New Oxford PA which is pretty close to the MD line , I know exactly what you are talking about . I am trying to find away into one of those hundreds of distribution centers , but knocking on the door and asking if I can shoot inside probably isn't the best approach lol 
 
Upvote 0
85 is pretty low and 18 is a pretty light pellet right? Before getting too frustrated I’d try increasing both.


Heated warehouse ? I live in Shippensburg and between the MD border and Harrisburg there should be a distribution center that would work. Gotta be hundreds along the 81 corridor.
Click to expand...

85 is pretty low but I am pushing the 18 grain pellets at about 875 FPS on average which from what I've seen and read should be a good speed for a diablo shaped pellet . I am going to mess with turning the regulator pressure up and see what effect that has. 

I live in New Oxford PA which is pretty close to the MD line , I know exactly what you are talking about . I am trying to find away into one of those hundreds of distribution centers , but knocking on the door and asking if I can shoot inside probably isn't the best approach lol
Click to expand...

Get a part time job as a night watchman. Have the gun, pellet trap and a rag in the car for when everyone goes home. The rag is to hang on the security camera while you shoot.
 
  • Like
Reactions: mohidris017
Upvote 0
You’re just wasting lead chasing those numbers in your house. What you can do is open the valve all the way then follow the proper procedure for finding a good second reg setting. You want to wind up around 900fps when you back the hammer wheel down to the knee of whatever reg setting you found that gave you around 930fps maximum speed. Then you can go outside and test accuracy. Maybe turn the valve in a little at a time to see if it tightens your groups. The valve adjustment is what changes dwell. Dwell is how long your valve is open. Once the gun is shooting great, then you concern yourself with ES and SD numbers if you feel it’s necessary. If you don’t understand any of what I wrote then it’s time to put the gun in its case and do some research and reading.
Click to expand...

Thank you Vetmx , I'm pretty sure I know what you are describing . When you say "valve" are you referring to the knob under the barrel that can be turned in our out by hand revealing the lines on the stem ? 
 
Upvote 0
You’re just wasting lead chasing those numbers in your house. What you can do is open the valve all the way then follow the proper procedure for finding a good second reg setting. You want to wind up around 900fps when you back the hammer wheel down to the knee of whatever reg setting you found that gave you around 930fps maximum speed. Then you can go outside and test accuracy. Maybe turn the valve in a little at a time to see if it tightens your groups. The valve adjustment is what changes dwell. Dwell is how long your valve is open. Once the gun is shooting great, then you concern yourself with ES and SD numbers if you feel it’s necessary. If you don’t understand any of what I wrote then it’s time to put the gun in its case and do some research and reading.
Click to expand...

When I was tuning my MKII I was aiming for about 950fps (slugs) so I tuned it to 1000fps (max) and then used the valve to decrease the velocity instead of the hammer spring to get to the 950fps. I'm guessing by your post I did it wrong?
 
Upvote 0
Corvid, you will want to watch the end of your shot string as you approach refill time when you do a generic tune like that. Having your hammer strike for a given reg pressure set at max then trying to control things with the valve only will make the gun damn near impossible to stay accurate from a fill all the way down to a refill. All those numbers on the hammer wheel are there for a reason. The way you’re tuning your gun the wheel is useless. I’ve tried the “Internet” tune on my gun just for the hell of it because I saw guys doing it on more than one occasion. You will not get away with it with slugs. Get that gun close to the knee with the hammer wheel if you want a chance at accuracy across a full fill.
 
Upvote 0
I had a simular exp tunning my compact with 18s.

The way my gun came tuned from UA was dead on accurate and super quiet. but had a poor spread and std dev. I started tuning up from my 100ish bar 870 fps to get better chrony numbers. I achieved great numbers but gun shoots lil rougher now. had more of a ping (to the shooter) and some recoil. still accurate but defiantly had to follow thru more on my part.

I actually lowered macro (was on 16 to 10) and slightly went up a couple digits (from 2 to 4)on the micro. i left the 2nd reg alone. this increased fps to 920ish. then i adjusted the valve knob to lower my fps to just under 900fps on avg. still dead nuts but required more effort on my part.

Still new at this as this is my first pcp but i think i need to come up on the reg 5 to 10 bar maybe to give more resistance to the hammer. not sure.



I haven't been able to shoot as i didn't listen to Ernest Rowe. I didn't use the box end of my wrench when i removed the valve housing and it deformed. New one should be here tomorrow tho.

Dont know why your accuracy would be suffering?

Try to follow your pellet and watch the impact in the scope. Concentrating on that helps your hold follow thru the shot!
 
Upvote 0
No you don’t stink! But, Yes! It’s important, especially with shorter barrels, compacts will require a very different tune, quick and snappy! I would highly recommend less hammer and more reg, this will help you close the valve faster and before the pellet leaves the barrel which is a total waste! Right?

the 18’s are not light for a compact, they are after all called heavy’s? If you just hit the hammer harder? (Which opens the valve more/longer) you will need to oppose that with the valve spring adj to control dwell.

Higher regs create a lot of friction on the valve closing it faster and usually making them significantly more quiet and usually consistent, if you have a dwell issue? It can make significant improvements in accuracy! Unfortunately, heavy or max hammer and low regs are popular right now? I really don’t know where it originated? Bad,bad. I hope this helps, I wish everyone struggling with this could have samples of both, so they could see, feel and hear the difference👍🏻 Just my opinion? Do with it what you will, I loved Spam until I tasted a good ribeye. 
 
Upvote 0
Exactly! I never even touch the valve adjuster. I let a little higher reg pressure create the back pressure to close the valve faster. Low regulator pressure is not efficient at all. Yes, you get more shots because you’re at a lower pressure, not because it’s efficient. Need to find the sweet spot for both. A quick “sip” of high pressure air is more efficient than a longer “burst” of low pressure air. Bob Sterne has written some great articles on this stuff.

Stoti
 
Upvote 0
Corvid, you will want to watch the end of your shot string as you approach refill time when you do a generic tune like that. Having your hammer strike for a given reg pressure set at max then trying to control things with the valve only will make the gun damn near impossible to stay accurate from a fill all the way down to a refill. All those numbers on the hammer wheel are there for a reason. The way you’re tuning your gun the wheel is useless. I’ve tried the “Internet” tune on my gun just for the hell of it because I saw guys doing it on more than one occasion. You will not get away with it with slugs. Get that gun close to the knee with the hammer wheel if you want a chance at accuracy across a full fill.
Click to expand...

Thanks. I'll use the Power Wheel to bring the velocity down with the valve wide open.
 
Upvote 0
I'm still new to this too so give me some slack.:)

It is my understanding that the valve is adjusted last by turning out until the velocity stops increasing. Otherwise, the valve is staying open unnecessarily long wasting air and possibly affecting turbulence behind the pellet/slug. 

Also, I was confused at first with the micro/macro wheel purposes. All that matters is what the sliding scale reads near the micro barrel adjuster. No surprise if you dial down the power wheel to 10 from 16 but increase the micro adjuster to from 2 to 4. Mathematically, you doubled the hammer tension and velocity will increase. 

Again, just trying to help with things I've learned in the past 6 months. 




 
Upvote 0
I'm still new to this too so give me some slack.:)

It is my understanding that the valve is adjusted last by turning out until the velocity stops increasing. Otherwise, the valve is staying open unnecessarily long wasting air and possibly affecting turbulence behind the pellet/slug. 

Also, I was confused at first with the micro/macro wheel purposes. All that matters is what the sliding scale reads near the micro barrel adjuster. No surprise if you dial down the power wheel to 10 from 16 but increase the micro adjuster to from 2 to 4. Mathematically, you doubled the hammer tension and velocity will increase. 

Again, just trying to help with things I've learned in the past 6 months. 



Click to expand...

I welcome all input. I'm learning as i go.

No matter how much reading or how many videos watched one really doesn't get things till they do them. Videos, reading, and advice can shortn the learning curve a great deal though.

It took me more than a few macro adjustments to realize the micro wasn't static and moved with the macro. lol Because of this even moving the macro from 16 to 1 the micro increased and so did velocities. from 870s to 890s fps. So for other newbs like me to really compare macro shot strings you have to keep your micro constant as well. Meaning returning it to a chosen micro setting after moving the macro. 

My understanding of the valve wheel is to tune for a higher velocity with the valve all the way open then slowly bring it in to your desired fps there by ensuring the valve was closing before the projectile left the barrel.

Stoti suggested articles by Bob Sterne. I read a few. They do shed light on hammer spring air pressure dynamic. The only thing is one has to keep in mind with the adjustable valve everytime you change it (or your 2nd reg) your shot string would change. The sterne articles were with a set reg and valve setup.

I'm assuming the reg creep issue on double reg guns wouldn't be applicable?

Way more testing is required to even shoot what and how i want to shoot let alone complete shot strings at varying valve, reg, barrel length parameters to find ultimate efficacy....lol Baby steps :)

Ughh i cant shoot till my valve stop gets here! :(

To cold anyhow i suppose.
 
Upvote 0
As Vetmx eluded to.....leave the valve adjuster on the fourth line and forget its even there. It's there for the finest adjustment after you have a reliable tune.

No other gun on the market has or needs one to shoot consistent groups and numbers. 

Tune with the reg pressure and hammer strike. Correcting a bad tune with limiting valve travel is just .....putting a band-aid on a bad tune. 



6000 pellets went through my mk2 of various weights. Never had to touch the valve adjustment. High reg pressure and slugs is where it may need fine tuning. 
 
Upvote 0
As Vetmx eluded to.....leave the valve adjuster on the fourth line and forget its even there. It's there for the finest adjustment after you have a reliable tune.

No other gun on the market has or needs one to shoot consistent groups and numbers. 

Tune with the reg pressure and hammer strike. Correcting a bad tune with limiting valve travel is just .....putting a band-aid on a bad tune. 



6000 pellets went through my mk2 of various weights. Never had to touch the valve adjustment. High reg pressure and slugs is where it may need fine tuning.
Click to expand...

From my limited exp (only1500 pellets through my m3 compact) valve adjustment may be more necessary on a short barrel high power tune due to the op dwell time concerns. And even that may be a result of your aforementioned higher reg pressure required to get high power in a short barrel configuration. Lots of variables to consider which maybe your advice of leaving the valve alone until the gun is tuned be prudent.

When my valve stop gets here i will proceed to tune for mid weight slugs in the compact and find out for sure. One of the reasons i got the impact was to tinker anyhow!.

I have only really tuned for the 18 gr jsb pellet. After i upped the fps the valve ended up at just less than 4 lines....wish they had hash marks on that thing!



P.S. I dint just set my hammer high and then adjust my valve. I went through the micro at a couple macro settings hash by hash and found the fps apex (knee) at round 920 avg then adjusted the valve in a lil at a time. just thought id clarify.




 
Upvote 0
All this micro and macro crap is not helping newbies understand the gun. Your valve adjuster is not a wheel, it’s a knob. You don’t measure the valve setting by lines, you measure it with digital calipers. It just gives a generation of airgunners who like numbers and are lazy a drain to circle. If you want to understand what a micro and macro really are and what they truly do, watch Impact and Impact MKll videos. It’s becoming very obvious that these supposed shortcuts that FX provided with the latest gun isn’t helping guys, it’s hurting them. And wasting lead.
 
Upvote 0
All this micro and macro crap is not helping newbies understand the gun. Your valve adjuster is not a wheel, it’s a knob. You don’t measure the valve setting by lines, you measure it with digital calipers. It just gives a generation of airgunners who like numbers and are lazy a drain to circle. If you want to understand what a micro and macro really are and what they truly do, watch Impact and Impact MKll videos. It’s becoming very obvious that these supposed shortcuts that FX provided with the latest gun isn’t helping guys, it’s hurting them. And wasting lead.
Click to expand...

Yep super lazy airgunner here , I sold my Impact M3 and bought a Red Wolf . What's easier than Low/Medium/High.
 
Upvote 0
All this micro and macro crap is not helping newbies understand the gun. Your valve adjuster is not a wheel, it’s a knob. You don’t measure the valve setting by lines, you measure it with digital calipers. It just gives a generation of airgunners who like numbers and are lazy a drain to circle. If you want to understand what a micro and macro really are and what they truly do, watch Impact and Impact MKll videos. It’s becoming very obvious that these supposed shortcuts that FX provided with the latest gun isn’t helping guys, it’s hurting them. And wasting lead.
Click to expand...

Yep super lazy airgunner here , I sold my Impact M3 and bought a Red Wolf . What's easier than Low/Medium/High.
Click to expand...

For Real?
 
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu