Jump to content

Archived

This topic is now archived and is closed to further replies.

Airsoft-Ed

Putting a debate to bed.

FPS vs. Range.  

27 members have voted

  1. 1. Does increasing a gun's fps, increase its range? (Read the OP before voting)

    • Yes
      23
    • No
      4


Recommended Posts

Warning: Long technical read ahead. Alternatively, you may think of it as a "Tedious Ed Essay" in which case, you're a penis.

Grab your breakfast and get stuck in.

READ IT ALL BEFORE VOTING - I'm hoping to see every vote go one way, unless there's an epic flaw in my argument that I'm missing, but the number of times I've seen people argue about this until the cows come home and swear blind that they're right when they're arguing for the wrong side, it makes my brain cry. I'm arguing on the side of proven science fact, vs opinion. Don't get it wrong again people, I'll hunt you down, I swear to that bearded dude in the sky who may or may not be there... Let's not get into another debate...

 

If I were to count the number of times I've seen people have the fps vs range debate, then I would lose count, lose hope in humanity and then hang myself to get away from everyone's massive, unparalleled idiocy. What annoys me the most is that it's usually a new player posing the question, "won't increasing my fps give me more range?" and they're often met with, "no, you don't need fps for range"

The thing is, you don't need fps for range because you can still fire up to about 60m with a properly set up gun, firing at 330fps (*1) But, where people fall on their face revelling in their own moronity (totally a word btw, I know 'cos there's no red squiggle), is that should you increase that fps to something higher, adjust the hop to account for the speed difference, and then add an appropriately heavier weight of BB, then you will ALWAYS shoot further than before. So you don't need fps for range, no. But to get more range, increasing the fps would be a good way to go.

Though obviously, do not exceed your site limits under any circumstances, or use heavier ammo to cheat the chrono, we measure the energy output, not the fps. Fps is just a simplified way to look at it, that's why we either measure with a .20, or have a conversion chart handy - which can be wrong because of barrel bore and length, but I'll not go into that. (Just chrono with .20s, saves the hassle and keeps people safe and insured)

Step 1 is to understand physics.

Physics lesson 1:
Things that go faster, take longer to stop and therefore travel further. Simple. BBs aren't controlled by wizards, the same rules apply.

A .20 flying at 500 fps is always going to go further than one flying at 450fps, 400fps, 350fps - any, lower fps. It might be by an inch, but it's still further.

Physics lesson 2:
Heavier things also take longer to slow down - it takes more energy acting on them to slow them down to the same extent.

So it stands to reason, that the faster a heavier thing goes, the further it will go. The faster heavier thing will always go further than the lighter thing travelling at the same speed, and the heavier thing will even go further if it's travelling slower than the lighter thing, so long as they both started off with the same energy behind them.

If you did want to get the lighter thing to travel a greater distance than the heavier thing, then you would have to massively increase its speed in order to make it force through the air resistance that can so easily slow it down due to its lighter weight, in comparison to the heavier thing.

(2*)

Anyway though, moving on, step 2 is to apply physics to BBs. Making sense of the last paragraph.

Pretend there's a gun firing at 350fps measured with a .2 and the hop is set to give it a perfectly flat trajectory - the second this bb leaves the barrel, gravity and air resistance will act on it. Gravity pulling it down, air resistance slowing it down. Hop will resist gravity for a time, but this time depends hugely on deceleration, if the bb loses its speed, then it loses its spin, therefore losing its battle against gravity and by extension, killing its range before it can go much further.

Because it's a .2 and it's light, air resistance acts on it quickly and its speed bleeds off in no time at all. After 20m it will have lost a significant chunk of its speed and the hop will have become significantly less effective than it was over the first 10m.

Now fire a .25 from the same gun - it will leave the barrel at a slower velocity, depending on the barrel bore and length it could be travelling anything between about 310 and 330fps, but the point is, it's slower.
Now, because of physics lesson 2, the air resistance has to work harder to slow this BB down, so although it started off going slower, it also decelerates slower and it ends up travelling further than the lighter BB. Once this BB passes the 20m marker, it will be travelling faster than the .20 was at the same point, despite starting off going slower. Just the weight dragging it through the air and requiring more air resistance to slow it down, allows it to maintain the speed it started with for a much longer period of time, allowing it to maintain its hop effectiveness, and battle gravity for longer.

So what's this? More range from the same gun, with heavier ammo? (It's been scientifically proven - http://arniesairsoft.co.uk/?filnavn=/articles/fps_dist_time/fps_dist_time.htm) But you said more fps gave greater range?

Ah, well you see, the thing is, greater BB weight also gives you greater range, so long as the fps post weight increase is still high enough to propel the BB a decent distance anyway, you'll always see a range increase - it's all about balance. If you're only firing at 300fps, then anything more than a .2 is probably going to be too much. Why? Because gravity doesn't scale down like your fps does when you add heavier ammo, and your hop's effectiveness actually depends on the speed of your BB to cause it to spin and create the lift.

For 320 and below, I'd use .20s.

For 320 to 350, I'd use .25s.

For 350 to 420 I'd use .30s.

For 420 to 500 I'd use anything higher, depending on the effectiveness of your particular hop.

 

Things like .23s and .28s are kinda like intermediate rifle rounds in my eyes - The BB equivalents of 6.8mm ammunition, use them for greater punch at shorter range, in CQB. Or greater accuracy at shorter ranges in woodland, stuff like that. If you wanted to fit them into the chart I've just created, then I'd say to use .23s firing at around 340fps and .28s firing at about 360fps if you wanted a place to start to have them working best for your range and accuracy.

 

Of course, this is just me musing what would be best, based on my experiences with some of the BB weight at some of those fps levels. By all means experiment with all of it to find the best use of what weight with which speed for your style of play, I just thought I'd provide my own rough guide.

One thing is certain though, so long as you don't go too heavy for your fps, heavier ammo will always give you greater range than the lighter stuff.

So if we upscale to snipers firing at 500fps, they tend to fire .40s and higher out to 80 or so metres. A good 20 to 30m further than the effective range of most AEGs. If we apply the idiot's failed physical principles to snipers, then you'd assume people would be happy to run them at the same fps and use the same BBs as AEG, but just use an ultra pro hop unit and rubber to give them their advantage, right? But they don't, they use heavier ammo fired at a much higher velocity because that is how you get more range!

The reason they don't use .20s is because as mentioned before, lighter BBs bleed off their speed stupidly fast, the speed at which they decelerate increases exponentially the higher their velocity is. The faster they travel, the more air they hit, the quicker they slow down. So you use heavier BBs, they're slower with their increased weight, dragging themselves through the air, almost despite the air resistance, reaching out and hitting targets to a significantly greater range.

Although .46s come out of the 500fps sniper at around 330fps, they stay at 330fps for the majority of their flight time, and end up hitting with a much harder punch, even out to extended ranges of 50m or more. In my experience BBs are at their most stable when travelling at between 330 and 280fps, so I would say that if you use heavier ammo to put your gun's chrono reading within that boundary, post weight increase, then that will be your key way to get the most out of it.

I'd bet money on it in fact.

If I had the time then I'd get a proper tuned sniper, a DMR, an AEG and a pistol together, measure their fps readings at various ranges and then make a graph showing the points at which their fps readings match, you could visualise it by having a sniper at the back of the range, firing past the DMR, firing past the AEG etc, then the DMR would stand at the point at which the sniper's in flight velocity matches that of the DMR's muzzle velocity and then you'd have the AEG down range of that, standing where all 3 guns' fps readings meet, then the pistol at the end, with them all getting closer towards the end of the range as the deceleration caught up with the BBs.

You could also use the data gained from it to make a variable MED for snipers, working out the exact joule output for any given range. You could set a site's MED up so that a sniper never hit harder than an AEG, or whatever you wanted.

 

Does that make sense to anyone other than me? What about the rest of the post?

I just lack the mathematical knowledge to work out the rate of deceleration of each BB and each speed to put it all together.

TL;DR heavy BBs go further, especially if they're going faster. Range is increased by increasing fps.

 

1*

though you'd struggle to do that with .20s - .20s are the BB weight for noobs (just throwing it out there). .25s are the way forward. I would suggest that they become the standard weight, but then all the noobs still using .20s wouldn't be at a disadvantage anymore and it'd be harder to call them noobs...

 

2*
Adding to this, I don't think it would actually be possible to make a .20g BB in airsoft, travel further than any heavier weight airsoft BB, irrespective of the speed you made it go. If you had a sniper tuned to hit a target at 80m using .46s and firing at 500fps measured with a .20, then I'd bet you'd have to fire the .20 at around 800fps or more to make it travel that far, and you'd still need the hop present to battle gravity, otherwise the highly aerodynamic-less shape that is the BB would be grabbed by gravity and then just immediately nosedive into the ground, because it's shaped in a way that allows it to be pulled around by whichever force has the greatest effect on it, in this case gravity. But since applying hop to a BB travelling at that speed would be next to impossible without annihilating the hop in the process, or maybe even the barrel and/or the entire gun, it'd just be impossible to keep it flying true long enough to beat the heavier ammo.

Share this post


Link to post
Share on other sites

My breakfast just consisted of: 10 bowls of cereal, 23 slices of toast and 13 glasses of orange juice...

Share this post


Link to post
Share on other sites

I'm not voting, because whilst the answer to the question is 'yes' it just comes across too simplistically as a yes/no argument (particularly as most people won't read your whole argument).

 

If I have a sniper rifle that fires 400 FPS on .20s and I up the FPS to 500 then yes, it will increase the range (as long as the hop is adjusted correctly). But most of the time these arguments come up along these lines: "my stock M4 is firing at 320 FPS on .20s, if I up the FPS to 350 will it increase the range?" Now whilst the answer is theoretically 'yes' I'd tell this person not to do it. The range gained by doing this would be minimal and they would be far better off increasing their BB size, improving their hop and taking a look at their barrel (not to mention the fact that keeping your gun too close to 350 could easily see you failing a chrono).

 

But, if it makes you happy, yes, the answer is yes.

Share this post


Link to post
Share on other sites

Warning: Long technical read ahead. Alternatively, you may think of it as a "Tedious Ed Essay" in which case, you're a penis.

Guilty.

 

 

 

It does increase range, it can't be denied as it's basic physics. How much is the key factor, when people say FPS doesn't increase range, it's often in the context of someone asking if it's worth upgrading their gun from 330 fps or so to 350 etc and so they're told not to bother and spending money on other parts is a better thing to do- such as hop up bits.

It will make a difference, it's just not going to be a large increase unless a substantial amount is added, otherwise people with sniper rifles and dmrs would be wasting their time.

Share this post


Link to post
Share on other sites

If your RIF in inaccurate and built with sub standard parts and has BB's flying all over the place at 300fps at random then increasing to 350fps isn't going to gain you a lot of range if at all.

 

You yes/no answer is just to simplistic for an argument that has so many variables. Therefore I cannot vote.

 

But in a perfect world where every RIF has the best barrel, hop, air seal etc etc then increasing the fps will make your BB travel further as physics tells me so.

Share this post


Link to post
Share on other sites

I get that contextually it's often more a case of not being worth upping the fps, but most people don't go on to say, "just not enough to be worth it" so you get all these annoying people continuing to say that fps doesn't effect range until you end up with clueless people spreading it to other clueless people and the myth is born and immortalised in the souls of halfwits. If I bought a gun and it chrono'd at less than 300, I'd get a tightbore, or change the spring to get it into the 330 region, at the very least, 'cos you will notice it.

 

It also keeps the myth going around that TM have magic hop, they don't. They're nothing overly special about them at all, they don't have range any better than anything else; A CYMA AK on the chrono limit, using the correct weight ammo, will outrange any TM firing at 280 every single time, I've seen many a TM user try to boast about their range, only to see it and be woefully unimpressed, especially on the TM57 and SCAR L recoil, though I do think that both users had no idea what they were doing with either of them, the TM M4 recoil I tried was pretty impressive.

It's like buying a TM doth descendeth a mist of illusionary superiority - based on a myth. 20-30fps is enough to make a difference, I found out at Anzio when I had to drop my L85 from 353 to 328, a difference of merely 25fps, but it made about 10m of difference, especially noticeable when firing from an elevated position. If you're used to the same gun with the same performance week in week out for more than a year, then every little change will catch your eye, and my ability to hit people changed a lot.

I'd argue that when new players ask about upping the fps, they often suggest buying a new spring - I think that might be part of why people say not to bother, 'cos for a new player it's effort and a risk, they might screw the gun up or something. If they're new people aren't going to know what their technical skills are like, so it's just easier to say, "oh don't do that you'll not notice a difference" - getting a new barrel would effect their range and accuracy, as well as boost their fps and oddly enough, it boosts it by about the same amount as I noticed can make a difference.

This is actually genuinely intriguing me now...

Perhaps TBBs actually increase performance by subtly upping the fps, decreasing the BB's time to deviate by making it reach the target faster, thus giving the illusion of accuracy and as a result, better effective range/range in general.

I wish I'd done maths at A-Level and Uni, I bet you could get a doctorate for studying this shit in depth lol. "The ballistics of BBs" PHD

You'd be a bullet Dr. :P

Share this post


Link to post
Share on other sites

I think a better way of putting it would be more energy = more range. Increasing FPS with .20g BBs so you can use heavier ammo at lower speeds to get more range as that ammo carries it's speed for much longer.

 

Also, your point about the 280-330 fps region being the sweet spot for BB flight speed (irrespective of weight) I think is absolutely correct. As I'm sure everyone knows, the faster something goes the more air resistance it encounters (exponentually so, double speed doesn't equal double wind resistance, it's way more!). 2 objects of the same size/shape displace the same amount of air so have the same wind resistance acting upon them and will lose energy to that resistance at the same rate. The heavier BB travelling at the same speed as the lighter BB will therefore retain its energy for longer and travel further.

 

Hop up is still the most important factor though. A 500fps sniper with no hop will be outranged significantly by a 250fps pistol with a properly set hop. In the end, gravity trumps wind resistance!

 

In short; I vote yes, but with a big caveat that if your hop up is shit then all the FPS in the world won't help!

Share this post


Link to post
Share on other sites

I think a better way of putting it would be more energy = more range. Increasing FPS with .20g BBs so you can use heavier ammo at lower speeds to get more range as that ammo carries it's speed for much longer.

 

Also, your point about the 280-330 fps region being the sweet spot for BB flight speed (irrespective of weight) I think is absolutely correct. As I'm sure everyone knows, the faster something goes the more air resistance it encounters (exponentually so, double speed doesn't equal double wind resistance, it's way more!). 2 objects of the same size/shape displace the same amount of air so have the same wind resistance acting upon them and will lose energy to that resistance at the same rate. The heavier BB travelling at the same speed as the lighter BB will therefore retain its energy for longer and travel further.

 

Hop up is still the most important factor though. A 500fps sniper with no hop will be outranged significantly by a 250fps pistol with a properly set hop. In the end, gravity trumps wind resistance!

 

In short; I vote yes, but with a big caveat that if your hop up is shit then all the FPS in the world won't help!

Pretty much what I was trying to say, but worded in a more understandable, eloquent way, James ^_^

Share this post


Link to post
Share on other sites

This is literally A-Level physics. Some even GCSE. It's just the laws of momentum.

 

1. Momentum = Force x Velocity

2. Velocity or speed = distance / time

3. Force = Mass x Acceleration

 

So firstly lets explain the Momentum equation, So the force that is initially put on the BB x the max Velocity will be the max momentum of the BB. Hence, Force x Velocity = Momentum

Now as the BB leaves the barrel air resistance begins to take effect. Which is a force being put on the BB. So then we have a conservation of Momentum situation. Essentially momentum is being transferred to the air and the BB's momentum decreases causing Deceleration and the BB eventually stops.

 

So we can conclude that a greater Momentum will give you a greater range as the drop of will take longer

 

 

So, an FPS increase is essentially a higher Velocity. Now if we apply this to the 1st equation it will mean that a greater velocity will equal a greater Momentum. Therefor extending range.

 

Now Force = mass x acceleration. Here we assume that FPS remains constant annd apply it to the BB itself.

So, when we increase mass the force increases.

E.G.

1N of force = 0.20g BB x 5 m/s/s (acceleration)

1.5N of force = 0.3g BB x 5 m/s/s (acceleration)

All that changed was the mass (weight of the BB) which increased the Force.

 

Now if we have greater force we get a greater total momentum since momentum = force x velocity. Therefor an extended range.

 

 

Now Physics tells us that if you have a greater FPS or a greater mass BB that your range will increase. Anyone who disagrees is just wrong pure and simple. If they disagree I'm sure we can get everyone's favorite character for physics Sheldon Cooper to Bazinga you punks until you accept that FPS increase gives greater range.

 

Of course there are other factors but basic physics teaches us that FPS increase gives greater range and greater mass BB gives us greater range.

Share this post


Link to post
Share on other sites

It seemed like you were implying that we don't need fps at all and I was going to say that I could buy a cheap JBBG approved orange pistol with about 100 fps w/ .20g and expect it to shoot up to 60m if I replaced the hop...

 

But reading on to the other comments... It seems like you're now saying that you need fps....

 

Anyways, i'm only doing int 2 physics and I understand this.

 

 

Oh, and I voted yes

Share this post


Link to post
Share on other sites

Increasing FPS will always increase range, but this is a horribly worded poll question that puts no debates "to bed".

 

A better question would be: "Is FPS the only factor in the distance that a BB travels?" - then the answer is obvious.

Share this post


Link to post
Share on other sites

Warning: Long technical read ahead. Alternatively, you may think of it as a "Tedious Ed Essay" in which case, you're a penis.

You lost me early on, so I'll see what the poll ends up saying.

 

Looks like I'm a penis then.

Share this post


Link to post
Share on other sites

Increasing FPS will always increase range, but this is a horribly worded poll question that puts no debates "to bed".

 

A better question would be: "Is FPS the only factor in the distance that a BB travels?" - then the answer is obvious.

The poll question is: "Does increasing a gun's fps, increase its range?" What's wrong with that?

 

The question you pose doesn't answer anything. A lot of people claim that a low fps gun can match the range of a higher fps gun just by having a more effective hop up. My point is that this isn't true. Your question would be like asking, "Does a gun that shoots, fire further than one that doesn't?"

Share this post


Link to post
Share on other sites

Unfortunately the ballistics of spherical objects is an extremely complex subject and do not readily conform to the simple physics which we mere mortals can easily comprehend. Don't get me wrong, the answer to the poll question is without any doubt at all "yes" and i can only assume that whoever voted "no" did so out of sheer perversity, but there are a number of issues which i think you are either wrong about, Ed, or not grasping the importance of.

 

Firstly hop: the speed at which the BB spins is not a product of muzzle velocity, or FPS down range. Naturally the force applied to the BB by the air expanding behind it causes the BB to engage with the nub so, all things being equal, more force ought to mean more backspin. But all things are not equal.

 

The hop setting is variable; even with hop left alone once set, the compound of the hop bucking, like any substance under pressure, does not behave in a linear fashion, neither does the interface between the 'rubber' surface and the BB surface, and if the BB is forced to squeeze past the nub, it must also be squeezed into contact with the bottom of the hop unit, and the friction co-efficient of this interface will also not be linear.

 

Basically there are very good scientific reasons why all the variables within a hop unit combine into a system which is best approached with the 'artistic' part of the brain, rather than the 'analytical'. It's not ridiculous then to view hop up as 'magical', by which I don't mean that any eye of newt, toe of frog, or wand waving ought to help, just that it would cost tens, maybe hundreds, of millions to create an apparatus that could measure all of the variables accurately enough and simultaneously so that the interaction between variables could be analysed, so basically you are left with trial and error guided by experience. Therefore any freaky anomalies, such as for eg the hop effect in TM AK's, which does provide only a max 10m less range than a CYMA firing at 60-70 FPS higher (bearing in mind that CYMA AK range can be phenominal), or the range of the TM M14 Socom - easily matching average AEG's but firing at around 280FPS, have to be considered as important 'clues' in your own quest for a combination of parts and BB's that give you the best range in your climate.

 

You only need to watch BB's 'hop up' as they approach the end of their trajectory to know that FPS per se is not powering backspin. In fact what is happening is that forward momentum is running out whilst lift generated by backspin is still there. (Edit: and the vortex of air created by the backspin must have more effect at lower forward speed, since otherwise the BB would rise that much right out of the barrel - it doesn't, but this also demonstrates how it is that a slower moving BB could be getting more lift from its backspin than a faster one.)

 

It also needs to be pointed out that the air resistance is not acting purely against the BB. Although the density vs surface area argument for why heavier BB's travel further with the same initial energy is correct within its scope, I would bet another round object more precious to me that a mathematical model of how far a 0.25 ought to travel compared to a 0.2 would predict the heavier BB would go further than it actually does in practice. I'm sure that this would be because the air resistance is actually also interacting with the air turbulence created by the BB both in flight and spinning, which also creates an extremely complex system when it comes to analysing drag and the angle at which its vacuum effect affects the BB at various speeds and rates of spin...

Share this post


Link to post
Share on other sites

Oh common now, let's not be hyperbolically obtuse. I acknowledge the fact that, as an avid TM fanboy, FPS isn't anything near to everything when it comes to shooting further and more accurately.

 

But all the poll question seems to ask is: "Does gun A shoot further than gun B if A has a higher FPS?" - which in every case (assuming gun A is identical to B in every way - which I am not saying it would be) would mean a BB from A would travel further.

 

I just think the question has been over-simplified; I entirely agree with the fact that a decent hop and barrel is equally as important as the speed at which the BB leaves the barrel, but that's exactly what your question isn't asking.

Share this post


Link to post
Share on other sites

A lot of people claim that a low fps gun can match the range of a higher fps gun just by having a more effective hop up. My point is that this isn't true.

Ah, but that is true - or at least it could be. I'm agreeing with what Ian (I think) said in this regard.

 

I also see proffrink's point on this too, which is why I abstained from voting first and won the early abstainer award of excellence in abstaining.

Share this post


Link to post
Share on other sites

Can this thread get largest amount of writing and possibly the most boring award?

Share this post


Link to post
Share on other sites

Can this thread get largest amount of writing and possibly the most boring award?

Warning: Long technical read ahead. Alternatively, you may think of it as a "Tedious Ed Essay" in which case, you're a penis.

Nuff said.

Share this post


Link to post
Share on other sites

FPS Does have an effect on range to a certain extent,something around 380 but past that the wind resistance just flings the BB around unstably.

 

I remember seeing this claim on an old ASSF thread which I will attempt to dig up..

Share this post


Link to post
Share on other sites

OK, massively over simplified. The answer is, what you state as "basic physics" isn't necessarily correct.

 

If you are talking an ideal situation, then yes, a similar weight BB starting out at a greater MV will travel further than its slower brother. Also, a heavier BB started out with a similar MV will travel further than its lighter brother (given that the backspin caused by the hop is sufficient to create the lift required to overcome gravity)

 

There are all sorts of aerodynamic equations involved with this stuff, it's not "basic physics" by any means.

 

The rate of backspin (rpm) required to provide the lift needed to overcome gravity is much higher for a heavier BB. Lift comes at a cost (called lift drag) so a heavier BB, which requires far more lift than a lighter one, will actually experience more drag and therefore MIGHT (it's a trade off type thing which requires a fair amount of maths to work out the best compromise) actually slow down faster!

 

Also remember that applying more backspin requires a much tighter hop (and therefore a much higher initial energy input) to achieve. This means that your gun has to work a lot harder to accelerate that BB up to the same energy. This means that your gun will almost certainly not achieve the same energy level with a higher BB weight, unless it's specifically tuned to do so.

 

So, in answer to your poll, the answer is "it depends".

 

If you want me to go through the lift/drag equations I can, though it would mean dragging up some old uni work.

Share this post


Link to post
Share on other sites

Hey Scoob, you must be the person who can tell us exactly why the lift effect of backspin produces that hop up as the BB slows down...?

Share this post


Link to post
Share on other sites

Hey Scoob, you must be the person who can tell us exactly why the lift effect of backspin produces that hop up as the BB slows down...?

the back spin produces a area of high pressure, behind and above the bb, as the bb slows, the area of high pressure moves closer to the bb, increasing air resistance further, and "hopping" ;)

Share this post


Link to post
Share on other sites

If people know all this stuff, then why isn't it documented?! There needs to be genuine studies done on this sort of thing.

Share this post


Link to post
Share on other sites

×