Airsoft Sniper Forum banner

61 - 70 of 70 Posts

·
Registered
Joined
·
624 Posts
Can confirm about g&G here too, I see almost guy doing upgrade have to "replace" mosfet after a while.
 
  • Like
Reactions: Zero Roaster

·
Registered
Joined
·
48 Posts
Discussion Starter · #62 ·
Ported barrel vs Full barrel
Based on equal comparsion, where:
1) Ported barrel has enough air volume to push the barrel.
2) All other items are the same.

For example, same piston, M110 spring, 0.28g bb and 380mm 6.03mm inner barrel. So a 3/4 ported or a full cylinder can be used, coz a 3/4 cylinder produces enough air volume and a full cylinder does not over produce too much air volume.

Based on the above-
Same M110 spring pushing the same piston.
1) In the 3/4 ported system, the piston will travel faster from the point of release till it hits the back of the cylinder head.
2) In the full cylinder system, the piston will travel slower but compressing more air volume.
So far, I believe this is correct.
3)Same inner barrel and bb. If the 3/4 system is already slightly over air volume, the faster piston will push the 0.28g bb out of the barrel faster, right?
4) In the full barrel system, the slower piston will push the bb slower. And since the barrel is only 380mm long, the same 0.28g bb does not have enough barrel length to fully make use of the larger air volume to accelerate more, so in the end, this bb will exit the barrel at a slower speed.
I believe this to be correct, by science theory.

Of course, if the barrel is much longer than 380mm or the ported barrel is 1/2. Then the result will not be like this.

I am asking this coz if I start my build with a "standard" length M4/16, the barrel is about 363 to 380mm. Normally, stock cylinder will be ported 3/4. For target shooting that is not affected by weather, 0.28g bb will do fine (easy for me to buy and 0.28g is cheap). I also plan to change to a full cylinder, as I believe that it will be more consistent than a ported one. I also believe that a full cylinder will not produce extreme over air volume that will negatively affect a 380mm barrel and 0.28g bb combo. Agree?

That brings me to another question or situation, what if I do my build on a 303mm, 245mm or 205mm barrel? I am quite sure that a full cylinder is extremely over for 245mm and 205mm. Do you think a full cylinder can still be used for a 303mm barrel, combo with M110 spring and 0.28g bb?

Last question, I was told that a barrel of 200mm is enough for accuracy purpose (at short range). Longer barrel will not improve accuracy anymore. On top of that, if a barrel is over 300mm, it is actually harder to control, as other factors affect it more. Do you guys think it is true?
 

·
Registered
Joined
·
1,585 Posts
At short ranges, a good pistol will be accurate. It comes down to the shooter. hehehehe. No, really... I have a red dot on my revolver and it's quite accurate..and it doesn't even have a hop up in it. But, it is shooting at 440 fps. Now in the case of my 1911, it has an upgraded rocket valve/nozzle, and a few other tricks making it very accurate to 100ft with .3's as long as I hold it steady. Tied to a bench that takes out the kickback, it's spot on. Just for comparison's sake to a rifle...

Ok, that aside, on to the questions...

Yes and no on the cylinder thing. In my book, a ported cylinder allows for a faster rate of fire. Less resistance on the system...but of course, less usable air. Now, a full cylinder may not be of any real advantage in a reasonable fps build with a short-ish barrel (360mm or so). You're moving air for nothing.

The ported cylinder will allow for faster piston movement because there is less initial resistance on the piston, however, it does move less air than the full cylinder so the potential for the full cylinder is greater. I've experimented with both in the same rifle where the barrel, hop, everything else was the same except the cylinder. Using semi auto fire (for accuracy), no appreciable difference in fps and more than likely just wasting good air. In something with a long nose like an M14, the full cylinder really makes a difference as the BB is in that barrel longer and really accelerates from the full shot of air. The ported cylinder with a long barrel is really lacking.

So let's say you're building an M4 with a 363mm inner barrel. A 3/4 cylinder will be fine, so will a full cylinder. The only appreciable difference may be with full auto fire where the 3/4 cylinder has a quicker recovery time, so say you want a rate of fire of 20 or higher, the stability with the 3/4 cylinder should be better. On semi auto, none of this really matters except for system efficiency whereby you're just wasting air with the full pull.

In my latest CM project (M4 carbine) I have a stock 363mm aluminum barrel, a metal hop up, top secret hop and nub configuration, but the gearbox is using an M110 spring, ball bearings, a stock motor, stock gears, plastic piston (stock weight) and a 3/4 steel cylinder. The fps is rock solid at 394 fps (with a .2) and the rate of fire is 11 rps (I also use a 9.6v nimh nunchuck and a mosfet). The biggest things that affect the rifle's performance are the ability of the gearbox to deliver a predictable, consistent shot of air every time and the hop up's ability to replicate the spin every time.

Honestly? The inner barrel is of no consequence. I've tried a 6.02 stainless, a 6.04mm brass, and now the stock aluminum CM barrel, and other than the change in fps from the varying volume of the barrel, it hasn't affected accuracy in any big way.

If you can keep the fps between 350 and 375 (with a .2) it should be quite good with .28's. Oh and about long barrels, I love them. A pain on the field when there's lots of action, but the shot stability is terrific when you have it properly propped up. The weight keeps it stable. My EBR was brutal to haul around, but when you had it settled in, it was rock solid. The long barrel also kept it quiet to some degree and there was certainly a degree of stability with it I just can't get from a shorter rifle. I just treated it like an electric sniper rifle...slow steady shots, and keep the movement to a minimum.

Now, keeping in mind that the ammo is all the same, the added convenience and light weight of the CM makes it a much more versatile rifle....even if I do lose a little performance over the EBR...but not much, really.
 

·
Registered
Joined
·
48 Posts
Discussion Starter · #64 ·
Hi Zero... happy Good Friday
When you said that you love long barrel.... being more stable? How so? EBR is above 450mm, right? I doubt you are using 0.28g bb, right?
So far, I see all the longer barrel using 0.45g upwards. So i think that 0.28g won't match any long barrel.
There won't be weather affecting the bb in the range. There isn't much advantage for me to use 0.45g or heavier bb. Am I correct to say that only heavy bb benefits more from a long barrel?
 

·
Registered
Joined
·
660 Posts
Hi Zero... happy Good Friday
When you said that you love long barrel.... being more stable? How so? EBR is above 450mm, right? I doubt you are using 0.28g bb, right?
So far, I see all the longer barrel using 0.45g upwards. So i think that 0.28g won't match any long barrel.
There won't be weather affecting the bb in the range. There isn't much advantage for me to use 0.45g or heavier bb. Am I correct to say that only heavy bb benefits more from a long barrel?
When talking about cylinder to barrel volume, heavier bbs are generally better in a shorter barrel. Heavier bbs (I believe) also are less effected by minor hopup imperfections, which will keep the bb straighter, at least from my observations.
 

·
Registered
Joined
·
1,585 Posts
Hi Zero... happy Good Friday
When you said that you love long barrel.... being more stable? How so? EBR is above 450mm, right? I doubt you are using 0.28g bb, right?
So far, I see all the longer barrel using 0.45g upwards. So i think that 0.28g won't match any long barrel.
There won't be weather affecting the bb in the range. There isn't much advantage for me to use 0.45g or heavier bb. Am I correct to say that only heavy bb benefits more from a long barrel?
I was firing .3g BB's in the EBR, and the BAR, and in everything else AEG at my place. Even the last AEG I kept (the Combat Machine) is running .3's.

A long barrel allows the BB to accelerate to its full potential from the air in the gearbox so you don't need as much 'push' behind it to get it to go. It makes for a nice, stable shot delivery as it exits the barrel. If there's one rifle I shouldn't have sold it's the EBR-L and I still hate myself for doing it. hahahaha. It was SO good. Luckily the guy who bought it gave it to his kids to fool with and now the rifle is completely destroyed...I don't ever have to worry about facing it on the field. :tup:

Yeah, by a solid balance between the cylinder and barrel it made for a very quiet rifle with a very consistent and even temperament.

Y'know, as I read your comment you have to realize that the rifle is a combination of ALL the components working together..I know, I say that over and over, but it's true. If you do have a long barrel, you have to alter the gearbox to work with that. In the Combat Machine I have a 363mm barrel, and 6.08mm inner diameter. The BB still comes hauling out of there at 394 fps. I engineered in a little 'bleed' so that the BB coming out isn't too hot, or too unstable and that it stays very accurate. So, the gearbox is sandbagged on purpose....to match the barrel...and give the BB what it needs to fly right.

It's all about the BB....
 

·
Registered
Joined
·
5,356 Posts
Not sure if I have already posted it in this thread but here are the best barrel lengths for each weight bb when using a standard full cylinder.


BB weight Barrel Length for a 6.03mm barrel
0.2gm---------------435mm
0.23gm--------------430mm
0.25gm--------------425mm
0.28gm--------------420mm
0.30gm--------------415mm
0.32gm--------------400mm
0.36gm--------------380mm
0.40gm--------------355mm
0.43gm--------------345mm
0.45gm--------------335mm


These recommended barrel lengths can be changed a little. 50mm either side will still give you very good efficiency.
 

·
Registered
Joined
·
9 Posts
Hey @1tonne so I'm shooting 400 fps out of my ssg10 with .25 BBS with a 540 mm barrel. Do you think I'd have better over all performance if I put the 430mm back in?
 

·
Registered
Joined
·
5,356 Posts
Stick with the 540mm. The ratios I mention above are for an AEG. VSR/SSG10's have a bigger cylinder so this is the ratios I go off:
0.3gm bb use a 554mm barrel (15821 mm^3) = 2.26:1
0.32gm bb use a 530mm barrel (15136 mm^3) = 2.36:1
0.36gm bb use a 500mm barrel (14279 mm^3) = 2.51:1
0.4gm bb use a 470mm barrel (13422 mm^3) = 2.67:1
0.43gm bb use a 430mm barrel (12279 mm^3) = 2.92:1
0.45gm bb use a 400mm Barrel (11423 mm^3) = 3.13:1

So 540mm will be fine. You could even go a little longer with the 0.25gm but I would most likely stick with the 540mm long inner barrel. That was you will be able to also shoot 0.3gm bb's well.
 

·
Registered
Joined
·
9 Posts
Cool, Thanks for the info, I will have to play 4 games I think before I can increase fps and bb weight so that's a good tool to use!

Btw @1tonne and @SiliconeSword your posts and replies have been a tremendous help in weeding out what's beneficial and what's not at my point right now. So Thanks a lot to both of you!
 
61 - 70 of 70 Posts
Top