FPS VS BARREL LENGTH

ok this is what i got
ics m4 with the stock barrel(does not count i pulled it out and added a 14"barrel so i could cut it down)
this is not a range test only fps.




after first cut

after second cut

this is the total i cut off


ok test was the same gun,same crono,the gun was not pulled down between shots,
same .20 bbs,and the mag never was pulled from the gun,and it was tested in less than
five min.,10 shots each high fps reading( because fps will vary between shots after the 10th shot i fired the gun a few more times to show the high fps reading on the crono for the pics)
i.e.
shot one 404,shot two 405,shot three 410,shot four 400,and so on.so after the 10 shots i fired the gun to get a 410 fps pic.
3"= 14 fps(on my gun)
so is this airsoft law?? NO!!!
but from what i have found it looks like you should be able to mod your barrel
and not your gun to drop fps.so acz is 420 fps but sw is only 400 fps
i say call airdog and get a barrel and just swap it out.
if you do not trust yourself to pull your gun down DO NOT DO IT!!
airdog has some of the best airsmiths around and they can do any mods you want
and will do it right the first time.
thanks for your time
BOB

So did you fire the gun several times after each cut? What were the averages between each?
A test of volume of air in the cylinder vs. volume of air within the barrel would also be worth while.

the barrel tip was cleared and 5 shots fired before crono.
this was not a air volume test
this was barrel length and fps-plain and simple.
i have been told that barrel length does not affect fps
so i used one gun,one barrel and this is what i got.

The reason the fps is decreasing is because most likely your gun has type zero cylinder in it which is ment for longer barrels. When you put a shorter barrel on it thats why the fps is lower. Generaly guns with short barrels have ported cylinders. Thats why you are seeing an increase in fps

poopdaddy wrote:the barrel tip was cleared and 5 shots fired before crono.
this was not a air volume test
this was barrel length and fps-plain and simple.
i have been told that barrel length does not affect fps
so i used one gun,one barrel and this is what i got.

I was merely commenting to the fact that we only have 1 chrono reading after the barrel was cut that doesn't really tell us much. Anyone who has chrono'd a gun before knows that fps can vary 10 fps shot to shot, or it can even vary 20fps. The variable is not about barrel length it is about volume of air within the barrel vs. volume of air within the cylinder, much like the point that trent brings up.

so no matter what there is no way that the barrel length will change fps.
not on the ics
not on the m4 sniper
not on the jg s-system
but i have seen the same thing on all of them
and again i chose 10 shots and thats the high fps reading
i could have put up 30 pics but i dont think it would have changed the responses
but if i am wrong do the same test and post up your pics
thats what this is for.
all i wanted to do was show my findings
not get all of the variables as to why i am wrong.

I'm not saying that your findings are not worth anything I was simply looking for more information on your test. I am not taking a stance on the issue, or saying you are wrong about anything but correlation does not mean cause. For example it is a proven fact that if you talk to your plants they will grow larger. So because there is more sound in the room your plants grow and you should leave your radio on when you go out of town so your plants will grow bigger. Of Course Not! It is the fact that you are expressing more carbon dioxide in your breath when you exhale not that you are talking, you could achieve the same results by just blowing air on your plants. Ergo, correlation does not mean cause. Again I am not saying your findings are bunk all I am saying is that I wish I had more numbers to look at, and another good experiment that needs to be done is to compare volume of air within the cylinder vs. volume in the inner barrel. If I were to take your findings for what they are I would achieve amazing results with an inner barrel 1 mile long. Of course this is preposterous and I cannot imagine that you would think that is correct. There has to be a happy ratio and it all comes back to volume of air.

i'm convinced. changing barrel lengths on my previous experiments (with everything else constant) also affected fps.

-a|ex

sniper2525 wrote:The reason the fps is decreasing is because most likely your gun has type zero cylinder in it which is ment for longer barrels. When you put a shorter barrel on it thats why the fps is lower. Generaly guns with short barrels have ported cylinders. Thats why you are seeing an increase in fps

+1

That's the whole reason why they make ported cylinders.

-a|ex wrote:i'm convinced. changing barrel lengths on my previous experiments (with everything else constant) also affected fps.

-a|ex

word

Electioneer wrote:

sniper2525 wrote:The reason the fps is decreasing is because most likely your gun has type zero cylinder in it which is ment for longer barrels. When you put a shorter barrel on it thats why the fps is lower. Generaly guns with short barrels have ported cylinders. Thats why you are seeing an increase in fps

+1

That's the whole reason why they make ported cylinders.

so if i pull it down and check and its a zero thats why
and if its ported thats why


how bout you post up a pic of both cylinders and i will let you know
now i saw gains in fps on my sniper with a longer barrel
and on my ics pistol(and unless i am wrong both are ported)
i do not have a long barrel i can cut down for my sniper
but when i get a chance i will do some tests on my new project
its a jg s-system with a m130 ported cylinder
it shoots 468 now so we will see

maybe some cheap barrels at the swap meet
ps
i have cut down about six barrels so far and all my tests have come out the same
as far as my knowledge i have only been working on my own guns for a few months so i am still learning
but my guns shoot hard and so far good
i do not think i am a know-it-all but if it walks like a duck,quacks like a duck and swims like a duck
most of the time its a duck
but so far most of what i hear is its a chicken
and it could be a chicken,if it is i will let you know-but so far i see a bill not a beek
thanks for your input but show it dont just say it

Bro nobody is attacking you we are just looking for more pieces to the puzzle. Do I think that tightbore longer inner barrels have their place? Absolutely. But it's not just end all be all for every application. Looks like you ride bikes so that would be like me saying okay so bigger engine and you are going to have a faster bike. While on one hand this does make sense it is not the final say. There are several different things that are going on here that just a longer barrel.

it was a simple experiment. varying the length of the barrel without altering anything else to record a change.
the cylinder volume remained the same. the mechbox was untouched. the hopup was not changed either.

ported cylinders does affect fps. but it is irrelevant in this experiment. the cylinder was a contant and not a variable. i can understand poopdaddy's aggravation. avoiding the obvious can be disturbing.

-a|ex

its ok
it was just a simple test
one gun one change
nothing else matters
and it was only 14 fps
but that took a gun from acz legal to sw legal
and that was the test
no springs
no changes to the mech box
just a hack saw
and some time
thanks for the support
-alex

-a|ex wrote:it was a simple experiment. varying the length of the barrel without altering anything else to record a change.
the cylinder volume remained the same. the mechbox was untouched. the hopup was not changed either.

ported cylinders does affect fps. but it is irrelevant in this experiment. the cylinder was a contant and not a variable. i can understand poopdaddy's aggravation. avoiding the obvious can be disturbing.

-a|ex

Well you actually are wrong sir. A port in a cylinder actualy does affect fps in barrel length. A m16 for example has type o cylinder which means it has not ports what so ever. This is to compensate for the long barrel allowing the bb to go through the barrel at the same time the air does so the piston reaches the cylinder head at the same time the bb is traveling through the barrel. IF you where to have a short barrel on a type 0 cylinder the bb would leave the barrel early before the piston hits the cylinder head. If you dont beleive me this is backed by my 6 years gun teching reeds 3 years and ryans 6 plus years along with russ's 6 years as well. Giving a total of 21 years in experience against what you guys have to back yours up. Im not trying to bash on anyone but im just saying that making statemants that you may think are true and saying they are right may not actualy be all that entirely true. If you really want to make your test conclusive i would do the tests again with the same gun but with two different cylinders to prove our point.

you know what the barrel i used was longer than the stock barrel
and if you look at the pics you wil see that it is longer still
stock the gun shot 360
the longer barrel put it up to 410
2 dif barrels so it does not count
all that said you compare this with that
ok
i can do things on a motorcycle that most think cant be done
i have been riding since i was 13 thats 24 years
and there are guys out there that make me look like i need training wheels
so i always judge people by how they talk about other people in there line of work
and you know what know-it-alls don't know crap about 90% of the time
so take this at face value
i said this is not airsoft law
but you seem to think it is not true at all
but you see pics and i see words
so pop off with somthing else
i do not care
this works for me
there have been more than a few threads where people say i dont want to get shot by poopdasddy's guns
cause they shoot hard
so if this does not work just enjoy the fact that i am a idiot
but remeber bumble bees cant fly
there body is to big and wings are to small
and thats it

im not bashing your tests im just saying what alex said was incorect about the port in the cylinder. I was simply stating that the port in the cylinder plays a big role in fps increase with a barrel increase.

sniper2525 wrote:

-a|ex wrote:it was a simple experiment. varying the length of the barrel without altering anything else to record a change.
the cylinder volume remained the same. the mechbox was untouched. the hopup was not changed either.

ported cylinders does affect fps. but it is irrelevant in this experiment. the cylinder was a contant and not a variable. i can understand poopdaddy's aggravation. avoiding the obvious can be disturbing.

-a|ex

Well you actually are wrong sir. A port in a cylinder actualy does affect fps in barrel length. A m16 for example has type o cylinder which means it has not ports what so ever. This is to compensate for the long barrel allowing the bb to go through the barrel at the same time the air does so the piston reaches the cylinder head at the same time the bb is traveling through the barrel. IF you where to have a short barrel on a type 0 cylinder the bb would leave the barrel early before the piston hits the cylinder head. If you dont beleive me this is backed by my 6 years gun teching reeds 3 years and ryans 6 plus years along with russ's 6 years as well. Giving a total of 21 years in experience against what you guys have to back yours up. Im not trying to bash on anyone but im just saying that making statemants that you may think are true and saying they are right may not actualy be all that entirely true. If you really want to make your test conclusive i would do the tests again with the same gun but with two different cylinders to prove our point.

?? didn't we just say the same thing? i mentioned that ported cylinders affects fps and you wrote a paragraph to prove it... i appreciate your years of experience and thanks to dedicated players as yourself, us newbies are learning quickly on repairing and upgrading our chinese AEG's.

no need to change cylinders, the experiment was about barrel length, not ported/unported cylinders.

-a|ex

i just think you guys missed the point of the test
this was not about ports,cyl,or piston
i took a gun with a 6"barrel that shot 360
i put a 14"barrel on it-shot 410
i cut 2" off-shot 400
total of 3" off it shot 396
so you see one gun-no mods other than the barrel
so no matter what you think it worked
will it work on all guns????who knows(other than you)
but it worked on this gun
thats the point
if your gun shoot over 400 and you want to play at sw
dont tear it down buy a used $10 barrel
get a hacksaw try it
if it does not work change the spring
if it works swap your barrel out when you need lower fps
its alot cheaper if it works-if not its a few buck
sure beats just not playing

thats all

i gotta let this go tonight
you guys have fun

Talk about getting carried away with something guys. Personally, i'm not going to go buy a longer barrel and suppressor to conceal it to gain a couple more fps, which in the long run will be virtually unnoticeable when playing. It's just not worth it to me and there are too many factors to consider anyways. Whenever I am upgrading a gun I have an fps range to shoot for and I buy the parts that will get me there the most efficiently and reliably. It just isn't worth the time and money to drop $60 on a decent longer barrel to gain a few fps or a few inches in accuracy.

There have been tests that prove AND disprove the effectiveness of tightbore barrels. But you would have to account for any variation in the hop-up bucking for the control test to the experiment test, nub, etc. There are just too many factors that can effect the results with barrels. You also have to account for the hindsight bias of a tester who just spent $60 on a piece of metal and doesn't want to prove he just wasted that $60.

Bottom line, if you want to put a longer barrel on your AEG to gain some fps, go for it (just make sure you have the right cylinder for the barrel ). I'm not one to judge what you do to your guns and that is that.

Have a great day

I love when we get all get worked up on MAA.

sounds like you are all right in your own way

Thank you, Harris!