KWA M16 OR M4

[wake.joe]

Jester, it's painfully obvious that Sig doesn't want to argue. Yes, you are correct. In every way, an M16 will out perform an M4. Every time, hands down. Wether it's real steel (Round depending) OR airsoft. Longer barrel is always better. (Size, maneuverability, weight, etc. all put aside.)


So stop trying to make yourself feel superior with these dumb posts. For fucks sake.

[LiquidSnak]

Well, noone likes to be proved wrong, but if you start an argument, you should be prepared to finish it, especially on a mil-sim based forum.

[Jester316]

I'm not trying to feel superior, I'm trying to figure out why he believes the things he does. I also want to hear his justifications. I am truly curious as to why he is sticking to his point so fiercely.

[Amos]

Alright guys, I've remained quiet for long enough.

The point he makes regarding gas guns is a valid one, the gas is stored in a liquid state in the magazine, when it is released it changes into an expanding gas, it *generally* continues to expand until it exits the muzzle.

On an AEG, X amount of air is stored in the cylinder in its uncompressed state, when the spring is released, it forces X amount of air through the nozzle and down the barrel. When the air is completely expanded (as it was in the cylinder before the spring tension was released) there is no more pressure behind the BB, and after that point the BB will start to decelerate. This is why some cylinders are ported, and some are not. Guns with shorter barrels generally have porting farther forward and the porting is moved farther back as the barrel gets longer. The porting is cut in the cylinder in a place where theoretically, when the piston head crosses the line where it begins to create pressure (the blue line in my 'diagram') matches the volume of the barrel.


My apologies for the terrible artwork, but it shows my point.




A stock M14 will shoot farther due to it's longer barrel, but you (theoretically) cannot make a stock MP5K shoot farther by just putting a longer barrel in it due to where the cylinder is ported.

[Haloeclipse]

Jester, it's painfully obvious that Sig doesn't want to argue. Yes, you are correct. In every way, an M16 will out perform an M4. Every time, hands down. Wether it's real steel (Round depending) OR airsoft. Longer barrel is always better. (Size, maneuverability, weight, etc. all put aside.)


So stop trying to make yourself feel superior with these dumb posts. For fucks sake.

Jesters comments seem legit. Many people come to this site for information on airsoft, and we have a scientific debate going on about it. At the least, proving the point one way or another is information for other people to learn from next time this comes up.

Theres a side benefit of teaching people to back up an argument more thoroughly before arguing against the laws of physics....

[Jester316]

Amos, you make a great point. But what if your cylinder isn't ported? My m14 and my mp5 don't have ported cylinders, and I have no idea about my SCAR (CA SCAR anyone?). I think the porting is another topic altogether. Porting just looses valuble compression. If your cylinder isn't ported, I would think that since more gas is compressed, you would get a higher velocity. Yes, it is designed to "perfectly" match the barrel volume (or come as close as they can), but I would think that you lose some power. Has anyone tried this? Taken a stock gun, and just switch cylinders? I would be interested to see the results.

Yes, GBB's and AEG's are different, but they still operate on small amount of compressed gas pushing a bb down a barrel.

[allizard]

I have the same question about non-ported cylinder on shorter barrel gun. I don't think it's a matter pushing the air out and I honestly think this have something to with a combination of ROF and suction affect when the piston retracts.

Take this for an example. Use a non-ported cylinder assembly and non-ported piston head. We can tell if the piston head gives a good compression by closing the nozzle at the bottom and drop the piston in. If it's got a good compression. There will be resistance and the piston will either drop slowly or doesn't drop at all.

Now take that in reverse direction. Drop piston in first, then cover the nozzle. Try pulling the piston back. With a Non-porter piston head you can feel it's resisting to pull back.

So what's all this about.... imagine if your gun have one of this setup and combine with a high ROF and combine with a non-ported cylinder. You are sucking in same amount of air that you are pushing out. I think this is why the engineer to limit the amount of air sucking back in by porting the cylinder.

Now.... that said. This was the original design on the old TM guns. Now a days we have ported piston head and that solve most of the suck back issue.

BTW, This thread is extremely fun to read.

[Jester316]

I think the reason we don't see a suck back effect is because the bb is already out of the barrel. That is why it is prevalent in longer barrels. I don't think there has been much actual testing on this, other than, "I have a 520mm barrel, and the bb's don't get sucked back..." type of testing. If I had the parts and time, I would be doing all these tests. Ported vs. non-ported for FPS, length of barrel to see suck back with and without ported cylinder. I find this stuff very fascinating.

Side note, why is this thread "extremely fun to read"? I'm just curious.

[Nocte]

Please do an advanced search for 'barrel suck' and set the author to Nocte. Barrel suck doesn't exist, please don't make me go into it all over again.

[CommieHunter]

A quick and easy way to show that barrel suck is unlikely is to watch your tappet plate and air nozzle. EVEN IF there was a high likelihood of barrel suck occurring, your air nozzle has already moved to the rear by the time the piston starts to draw back. The air nozzle is no longer sealed to the hop-up unit and most air will come from the surrounding area. But that's off topic for the current discussion.

Porting in the barrel is used for efficiency. A short barreled AEG only needs X amount of air, a carbine needs XX, and a rifle needs XXX. XXX is the most air a cylinder can compress. When you fire a rifle, the piston head begins to compress the air in the cylinder. It continues to compress the air, some air leaves, the pellet begins to travel down the barrel. The design is such that the pellet leaves the end of the barrel right at the moment the piston head hits the cylinder head. The back-pressure that the bb provides allows the piston head to land somewhat gently on the cylinder head.

However, if you were to fire a carbine with a full seal cylinder, the air would begin to compress at the beginning of the cylinder. The bb would exit the barrel when the piston was not fully landed, and the piston head would then strike the cylinder head with no back-pressure. This is slightly inefficient, as more air than is needed is being compressed.

The one other factor is that when you fire a gun with a ported cylinder, because of the port, the piston will drop faster and encounter almost no resistance until the piston head reaches the port. This means that there is no energy wasted because the gun is only compressing exactly the amount of air that it needs.

Conversely, if porting were to reduce barrel suck, it would be most necessary in longer barrel AEGs, and nearly unnecessary in short barrel AEGs. Because the opposite is true, it stands to reason that ports are not for reducing barrel suck, but are more relative to air compressed.

[DMitri]

Amos, did you miss my first post?

He was saying that a longer barrel requires more energy for the bb to make it through. Which is true, however there's enough energy not being used that you don't need to compensate. (Unless you're sticking an M14 barrel on an MP5K with a ported cylinder.)

Ported cylinders are one of the first things I scrap in new replicas, along with plastic bushings.

While it's true that if you don't NEED the increased volume of air in the cylinder, it actually will lower FPS slightly*, we have a cap anyway, and there are plenty of ways to reach it.

*The piston moves slower at the beginning, the port serves both to reduce the volume of air to what is needed, and in turn allows the piston to gain full speed before affecting the bb.

I like the increased chance of unjamming my gun with an extra trigger pull.

But really I don't like the idea of the O-Ring sliding over a port 25+ times a second.

[Bush Killer]

But really I don't like the idea of the O-Ring sliding over a port 25+ times a second.

I was just thinking about that...I don't really want my o-rings getting trashed every 5k rounds...

[CommieHunter]

So you get taper cylinders like those in G&P and available from some manufacturers. They are larger ID at the back and they close to the proper ID at the point where a port would be.

[Bush Killer]

Sounds sexy...

But now we're super off topic.

Blah blah blah, M16 is better. Blah blah.

Get the M16.

Blah blah.

[Danger Corp.]

... interesting... I'll have to agree with jester and all the other people supporting the longer barrel= more accuracy and range theory; cause its true. Its not that to hard to grasp, I'm only 15 and i get it( mostly from common sense):). but whatever.. .. .. . blah blah blah blah, get what you want, blah blah blah, i think the M4 is a good choice, but thats my opinion, blah, ... .. .