Maximum fps

[The Disavowed]

I don't want to open a can of worms with regards to what is legal where or how friendly or unfriendly it would be to be shot with it, I was just curious for some input from more knowledgeable people. With all the talk about the Weagle shooting at a pretty high fps for a pistol, mention has been made about downgrading the fps, but that has made me curious about going the other way, ONLY in theory.

 

What I wondered was if I wanted to bump up the fps, how would I go about doing it properly, and at what point would the gun theoretically fail? I assume that if someone was stupid enough to make it shoot 1000fps then it would just blow itself apart, but could someone feasibly make a sniper rifle type pistol shooting 500fps without eating the slide when it shoots?

 

I know that valves and springs and gas all will also play a part, as red or black gas or c02 or hpa could be used, but I was thinking using green gas and not having to replace everything on the standard gun.

 

Again, this is just something I was wondering about and therefore wanted to understand more about, not something that I actually think would be a good idea to do.

[renegadecow]

Stick in a very tight bore (>6.03), Maple Leaf autobot hop rubber, and shave down the inner diameter of the floating valve some and you could possibly get 420fps on it, maybe more on green gas. A 10" barrel would bring it to 500 and up with higher pressure gas. More fps won't necessarily break anything like "eating the slide" unless maybe you do that by using CO2. However it's still possible to make a CO2 gun to shoot hot but not blowback too hard or enough to break anything as muzzle energy and blow back can be controlled/restricted separately.

[The Disavowed]

Thanks for the reply. I might try shaving the floating valve down on my browning hi power I am working on as that is rather meh, how much should I shave before I ruin it and it becomes ineffective?

[Guges Mk3]

You should try this on a better platform than a replica Browning HP.

[3vi1-D4n]

I had a Gas Tanaka M24 outputting on a warm 25*C day's first shot FPS of around 700fps, dropping to 550fps on the 2nd shot.  I didn't know this at the time.

 

My squad was on patrol game and we were contacted by a small hit and run group of 2-3 eny pers (were friends of mine on the opposite team), I had the bolt action and really shouldn't have rushed forward to try and get my team out of trouble. 

 

The enemy was hiding behind little obstacles of dense bushes around 5m diameter spread on a hillside, too thick to see through but you can hear the enemy hiding behind somewhere.  I fired 2 shots through one of those bushes.  I was around 15m/50ft away, was just trying to keep heads down.

 

First shot, first guy screamed in pain, 2nd shot the other guy fell backwards.  The first guy got hit in the shoulder and the bruise was the size of an egg, the 2nd guy got hit in the thigh but thankfully he had BDUs so it was baggy.  

 

We were working on assumptions of delivering suppressive fire and enemy location wasn't clearly identified, my mates knew I wasn't out to cause them harm.  Straight afterwards I took the M24 back to the car, came back with an AEG.

 

Normally, we do skirmish with rather high FPS, but nothing as high as 700fps.  I would say, anything exceeding 600fps is getting to too much damage to both the receiving people and the parts on AEGs and bolt actions.

[icolater]

Also high flow valves in the mag will alow more Gas to hit the bbu

[DarkLite]

I've built 1.9J (approx 450fps on a 0.2g) GBB pistols before for customers in HK.

 

WE G17 in one of those HERA glock-in-a-box kits with a fake suppressor to cover a 6.01x303mm barrel, 150% hammer spring and recoil spring, with an aluminium flute valve with a stronger flute valve spring. Running on green gas magazines with high-flow valves.

 

It's possible, and in the UK it's legal as long as the pistol is not capable of burst or full auto.

[Guges Mk3]

Also high flow valves in the mag will alow more Gas to hit the bbu

 

This is completely subjective and not a major factor in letting more gas to the BBU for all valves.  In some cases it is less.

[icolater]

This is completely subjective and not a major factor in letting more gas to the BBU for all valves.  In some cases it is less.

What do you mean?

[NonEx]

The thinking behind high flow valves being "useless" is that the amount of gas passed through the pistol before cut off is controller by the blow back and valve reset knocker.

 

But, IMO, a high flow valve will give you a more "forceful" release of gas and perhaps a snappier action, and possibly a slight bump in FPS.

 

Think of it like pouring 1L of water through a straw vs. a garden hose. The same amount will pass but at different rates and with different "force".

 

What he means by sometimes less is that if the gas enters more forcefully, and due to vapor action and whatever, the cycling of the gun and cut off of gas might happen sooner than with a normal valve, thus release overall less gas. Right?

[Dimitri MdP]

I've actually tried high flow valves in many guns, and most of them had no significant difference vs OEM, some had 10-15 FPS more, and some actually had 10-15 FPS less. 

The FPS is controlled by the nozzle's floating valve that cuts the flow towards the front as soon as enough pressure is built behind it, so a higher flow from the output valve will not affect FPS at all. Just like using higher pressure gases.  Furthermore, the overall flow is controlled by the valve locker, so again, no significant difference in recoil or gas consumption either.

To increase the FPS you need to either:

- Allow more gas to the front of the floating valve, which some people say can be achieved with a stronger floating valve return spring (I've failed every time I tried that mod), or try a 
- Make better use of the gas that went forwards, i.e. using a tighter and/or longer inner barrel so the same gas provides a better push to the bb.

[3vi1-D4n]

FPS in gas guns is a fascinating topic.

 

High flow valves in guns don't always work because its not just about the window of the gas valve body which lets gas through, its also about the gas flow through the main O-ring area.  If you bored out the window, but don't increase in the valve diameter, you won't get the necessary gas flow anyways.

 

Playing with the flute valve and flute valve spring tension to increase FPS has different effects on different barrel lengths.  For rifles, increasing flute valve spring tension works really well to increase FPS because the gas volume has time to be harnessed by the long barrel, but for pistols, you are just purging gas into space as the BB has already left the barrel.

 

The other detrimental effect of having a strong flute valve spring is sluggish recoil and vaporisation of gas on rapid fire, particularly in cold weathers.  On WEs I normally cut the flute valve spring by 2 rungs and chop the recoil spring a fair few rungs to make sure it works well in colder conditions.

 

Putting the flute valve resting position also has less effect on pistols, than on rifles for the same reason as above.

 

For pistols there are two things you can do to increase FPS:  1)  A new flute valve design (KSC or KJW style flute valve) which allows more gas flow in the initial flow, 2) Increase the hammer tensions, so more gas is released quicker (release impulse).

 

There is another way to increase FPS output, and that is by extending the length of the gas release striker of the firing pin.  This opens up the initial release period of the gas from the magazines for a lot longer.  I did this to a WE P90 (I lengthened the gas release pin on the release valve), WE MP7 (created a metal insert into the firing pin) and WE P228.  More kick and slightly more FPS.  P90 was getting from 380fps to 460fps.  MP7 from 370fps to 430fps, and P228 from 270fps to 310fps.

[Guges Mk3]

Adding to the discussion.

 

Gas in itself is a whole random set of factors.  Gas properties at various temps and pressure will affect performance.

The release valve will NOT always add FPS.  Gas pressure out of the mag due to ambient temps is another factor.  Many of these "High Flow" valves are nothing more than "another" type of valve that are just tossed in a bag that says "High Flow". 

I say this because,I know ( I have been/worked in the industry since the 20th century) some of these parts makers.  There is absolutely no quantifiable standard that would make one valve a "standard" valve and another a High Output/Flow Valve.

 

Operationally the other posters has touched on the factors that says HFV add or does not add to FPS.

 

And then you have operational issues.  When you release to much gas, your shot efficiency goes down.  So, there is a trade off.  FPS or shot count.

 

For cold weather play in MN where the temperature is ~10C in the winter.

 

The only option I have found that is a compromise is to lengthen the barrel and install a Ice Pick Valve.  Adding 20mm gets you a ~35psi boost with Propene (Not a spelling error) and the Ice Pick valve allows operational efficiency to drop down to 15 psi.  So you use all the gas and the pistol never vents.  But, you lose about ~20 fps due to it it's operational sensitivity to to less gas being used.  Nupro Black has similar properties to ET2200 and that averages about 25fps bump overall with an Ice Pick Valve.

[icolater]

I have them in my meu mags and they work great with a stronger hammer spring. IMO they work.

[Dimitri MdP]

For cold weather play in MN where the temperature is ~10C in the winter.

Just use Map Pro (propylene). At 10ºC it has the same pressure as Propane at 20ºC.

[Guges Mk3]

 

"Posted 18 November 2017 - 03:03 PM

Also high flow valves in the mag will alow more Gas to hit the bbu "

 

I have them in my meu mags and they work great with a stronger hammer spring. IMO they work.

 

Well, that is an additional factor.  The stronger hammer spring.  You left that bit of detail out in supporting your statement that the valves adds FPS.  By all factors it was a stand-alone comment about the valve adding FPS. 

 

Have you tested your stock valves with just the stronger hammer spring?  I surmise you will see a similar performance.

 

Dimitri,

 

Propene = Propylene = Methyl Ethylene (we are referring to the same thing under different nomenclature)

 

But, the Ice Pick Valve is an additional parameter that ensures full operation, increased efficiency and no venting due to chill down.  

Also high flow valves in the mag will alow more Gas to hit the bbu

 

[Dimitri MdP]

I'm really confused by why are you guys using stronger hammer springs. Gas flow is controlled by the valve locker, and the valve can only open so much. So it's more of a on/off switch. 

Striking the valve harder will not cause any difference at all, as long as the spring has enough tension to actually actuate the valve vs the output valve's own spring + gas pressure. 

 

Propene = Propylene = Methyl Ethylene (we are referring to the same thing under different nomenclature)

Yup... read that wrong and thought you were saying propane. That's why I choose to call it propylene, to prevent the confusion.

[renegadecow]

A stiffer hammer spring does make a difference. An easy example of this would be revolvers and NBBs but also applies to GBBs. The stroke length of the knocker is the same but the quicker the valve is opened, the higher the pressure spike behind the bb at rest. If you have a long enough barrel though this increase becomes less and less pronounced as the bb is able to accelerate fully from the expanding gas.

[Guges Mk3]

In addition, the heavier hammer spring will hold the valve open a bit longer too, letting more gas out.

 

Like the old J-Spec KSC M9, back in 2002.  The Valves would only allow a FPS around 288fps with .20g due to ASGK requirements.  Adding a 130% hammer spring resulted in a ~28fps boost to about 316fps.

 

I also got the pistols up to 333fps with .23g bbs with a M93R barrel. 

[renegadecow]

Nah man. Duration is all in the knocker and knocker lock. In most pistols the hammer is already being pushed back by the slide before the lock starts to disengage the knocker.

[Dimitri MdP]

The stroke length of the knocker is the same but the quicker the valve is opened, the higher the pressure spike behind the bb at rest. 

 

But a stronger spring won't cause any noticeable difference in valve aperture time. It's practically instantaneous, and will be with every spring you can toss in. Except in cases when the spring is severely below the required tension for the given valve / gas. 

 

Besides, and the key point in all of this discussion, the floating valve will compensate for anything that happens before

 

-----------------------

 

Like the old J-Spec KSC M9, back in 2002.  The Valves would only allow a FPS around 288fps with .20g due to ASGK requirements.  Adding a 130% hammer spring resulted in a ~28fps boost to about 316fps.

2002... was that even a modern-design GBB? (i.e. with reciprocating nozzle, floating valve, valve locker, etc)?

 

In addition, the heavier hammer spring will hold the valve open a bit longer too, letting more gas out.

It will certainly not. As soon as the slide releases the valve locker, the firing pin will go instantly back, allowing the output valve to cut the gas.

Stronger hammer springs will not make any difference in the time it take for the slide to release the locker, therefore, it will not affect the time it takes to cut the gas flow

 

------------------------------------------

 

 

the Ice Pick valve allows operational efficiency to drop down to 15 psi.  So you use all the gas and the pistol never vents.  But, you lose about ~20 fps due to it it's operational sensitivity to to less gas being used.  

I'm totally lost on what you mean by "operational efficiency / sentitivity"

[renegadecow]

The difference, while imperceptible can be significant. It's just like how you get a significant fps boost with hop up vs without.

[icolater]

You know your stuff Dimitri, it's so annoying when people try to explain something they know little about, LOL @ operational efficiency, that made me giggle, got to love Arnies sometimes.

[Guges Mk3]

If hammer springs do not account for any FPS gain?  Why do the even make them?  Why do they even work?  Why?  Because it release more gas Before the flute valve shuts and sends the slide back to reset the knocker.

 

Have you ever seen an Ice Pick Valve?  

What happens when you have a partially filled Gas mag and the temp of the mag is ~9C?  It will most likely vent in a puff of gas and you are out.

Watch this video.  Mag is ~1/3 full, it is ~9.4C and it fires several shots before we run it "Dry".  No puff, consistent ~270fps.

 

Icolator,

 

Just because you don't know me doesn't mean I haven't potentially been seeing airsoft in the 20th century ( I am actually published for modding and reviewing a Maruzen MP5K on Arnies - This is just to help you get to know me better).  My first Airsoft springer was in 1982.  A shell ejecting Daisey Model 59.  When did you get your first airsoft gun?  This is just a reference question.

 

And Operational Efficiency is a very valid term.  It's like MPG - Mile Per Gallon, but instead of miles and gallons.  It's BB's Per Mag.  So if you have a pistol and you are playing in 15C degree temps.  You may get about 20 shots out before your mag vents the excess gas due to low pressure not working the action and disengaging the knocker.  Thus that is your Operational Efficiency - 20, under that Operating Condition.  Now if the temp was say 35C, you may empty the whole mag of 26 bbs and fire an additional 12 bbs without adding more gas.  Now your OE is 38, for that Operating Condition.

 

This is Operational Efficiency of an Ice Pick Valve - All gas used for operation, none wasted in a gas cloud.

 

Operational Efficiency is quite high.

Being that this is Airsoft where the industry has no "standards", do not be surprised that in some parts of the world.  There are other terms and technology that you may not have seen or heard.  I wish to thank the Canadians that developed Ice Pick to extend operational efficiency in low temps.

[icolater]

Hey Guges, I meant no disrespect. I was 1 in 1982 LOL. Quick question about the ice pick, if it's so good why don't marui or any other gbb manufacturer use a similar design?