Fx impact plenum

[bucketboy]

we all know that a larger plenum allows the gun to breathe more easily but here in the uk the legal limit is only 12fpe. Although popular there seems to be more than a few issues with the impact running at sub 12 levels, most commonly, poor shot to shot consistency and too many flyers.

There are some other differences between the high power and low power versions namely different vp size, different tp size, the power of the hammer spring and the weight of the hammer but I can’t see those as being the cause of the problems as almost all other guns govern the power the same way without any detriment to the consistency or accuracy.

Does anyone think reducing the volume of the plenum will help? 

Also , even though the reg is stable with no creep, when stored for even a short period, the first one or two shots are all over the place, what could be the cause of that? X ring gripping valve stem maybe?



Bb

 

[edosan]

Hi, imo

1 - yes, less volume will make fps slow down a bit

2- an incorrect hammer spring tention is one if the reasons for low fps on first shots

Not a clue about sub 12

 

[Airgun-hobbyist]

Though I have a high-power (USA) Impact I too had the same issue with first shots being off due to regulator creep. Because your power settings are so much lower it may be a different issue, but to remedy mine I cleaned and de-greased the valve rod and hammer spring assembly. Then greased the o-rings, spring and rod portion only. I also added weight to my hammer with a brass bushing. Because you have different laws regarding power, the additional hammer weight may be a problem, but cleaning the hammer and lubing the spring and valve stem o-rings should definitely help keep things more consistent.

 

[Darren]

we all know that a larger plenum allows the gun to breathe more easily but here in the uk the legal limit is only 12fpe. Although popular there seems to be more than a few issues with the impact running at sub 12 levels.



Bb

Sorry to go off topic for just a second Bucketboy, but I am not aware of the UK laws. What is required to get the full powered version in your country? Is it so hard? Or don’t they allow them at all? I though I read something about FAC? (Firearms certificate?). 

What are the differences between the two? 

 

[bucketboy]

we all know that a larger plenum allows the gun to breathe more easily but here in the uk the legal limit is only 12fpe. Although popular there seems to be more than a few issues with the impact running at sub 12 levels.



Bb

Sorry to go off topic for just a second Bucketboy, but I am not aware of the UK laws. What is required to get the full powered version in your country? Is it so hard? Or don’t they allow them at all? I though I read something about FAC? (Firearms certificate?). 

What are the differences between the two?

You can get high power airguns but you need to apply for a “ fire arms certificate ‘ FAC, you have to be vetted by the police, you need a note from the doctor to say you have no mental issues, you need to have the house inspected to ensure it is secure including an approved gun safe, a letter from the land owner giving permission where you intend to shoot and the land has to be approved for the type of weapon being used. All in all, a royal pain in the ar$e. 

My circumstances would allow me to get an FAC with little or no issues but I have been shoot/hunting with sub 12fpe airguns for so long now, I can’t see much of an advantage ( other than range) an fac airgun has over a sub 12fpe.

Fac does have some disadvantages, decreased shot count (600 shots from one fill of an impact in .22 sub 12) ifac are louder, much louder, I see long range shooting on YouTube hitting birds at 100 + yards, one hit an the others fly off. With a sub12 @ 40 yards I can hit 10 or more before the birds realise something is wrong ( same goes for rabbits, squirrels and rats don’t even move even after you shoot 100) Then of course the safety aspect, I live in a small, heavily populated country, the distance an fac pellet can travel is significant, a slug even more so, no responsible shooter in the uk would ever shoot at a animal that was high in a tree or building with a slug, the potential consequences of a missed shot could be grave.

Obviously, in unpopulated vast areas the risk of accidental injuries are much less but to be honest, shooting at extreme distances with an airgun does not appeal to me, I would rather precisely place a pellet at 20 yards than take pot shots at 200yards.

Bb

 

[bucketboy]

Though I have a high-power (USA) Impact I too had the same issue with first shots being off due to regulator creep. Because your power settings are so much lower it may be a different issue, but to remedy mine I cleaned and de-greased the valve rod and hammer spring assembly. Then greased the o-rings, spring and rod portion only. I also added weight to my hammer with a brass bushing. Because you have different laws regarding power, the additional hammer weight may be a problem, but cleaning the hammer and lubing the spring and valve stem o-rings should definitely help keep things more consistent.

Thanks.



bb

 

[bucketboy]

Hi, imo

1 - yes, less volume will make fps slow down a bit

2- an incorrect hammer spring tention is one if the reasons for low fps on first shots

Not a clue about sub 12

Thanks



bb