Airsoft Canada - View Single Post

ThunderCactus · August 7th, 2018, 12:40

First and foremost; just because airsoft manufacturers build guns, it DOESN'T guarantee that they know what they're doing. If they built perfect guns, there would be no aftermarket mods or parts. And even if they did design a gun with all the mods and parts, they would still suffer losses from manufacturing.

Cylinder porting is a tradeoff of volume for pressure.
The lower the volume, the higher the pressure. This is how an M110 spring can shoot 380fps on a 420mm or 180mm barrel.

There are points of diminishing returns in multiple ways: (assuming M110 spring, 1.35j which would be 382fps on a .20)
If you are undervolumed, you may be shooting 1.35j with a .20, but find you shoot 1.2j on a .32
If you are overvolumed, you may be shooting 1.2j with a .20, and 1.35j with a .32
If you are grossly overvolumed, you may be shooting 1j with .20s and 1.2j with .32, but might also be at 1.35j with .43s
There's a balance point where you can be pretty close across the board. For example, my M14 is within <.05j across a multitude of BB weights.

It's a balancing act.
So manufacturers generally state with their cylinders "for 300-400mm barrels" or "for 200-300mm barrels". You want to be on the top end, so if you have a 229mm barrel, you'll want a 200-300mm port.
If you have a 285mm barrel, you'll want the 300-400mm port.
There are no real standards in airsoft manufacturing, so the same cylinder port could have different ratings depending on who makes it. Although it seems they tend to be rated by .20s, which is why you want to be near the top end; overvolumed a bit.

Now, all that being said, there's no reason for you to go from a 229mm to a 285mm barrel in the first place. You will not gain any accuracy, and you will gain exactly 56mm of range.
In airsoft, the sole advantage to having a longer inner barrel is making it easier to achieve higher fps, and a 205mm barrel can do 3.2j with the right build.
So just upgrade to a higher quality 229mm, and use a 200-300mm port, like a prometheus type D

If you have any other questions on how stuff works, it's probably already covered in this:
http://airsoftcanada.com/showthread.php?t=166583

August 7th, 2018, 12:40	#5
ThunderCactus Not Eye Safe, Pretty Boy Maximus on the field take his picture! Trader rating Join Date: Feb 2007	First and foremost; just because airsoft manufacturers build guns, it DOESN'T guarantee that they know what they're doing. If they built perfect guns, there would be no aftermarket mods or parts. And even if they did design a gun with all the mods and parts, they would still suffer losses from manufacturing. Cylinder porting is a tradeoff of volume for pressure. The lower the volume, the higher the pressure. This is how an M110 spring can shoot 380fps on a 420mm or 180mm barrel. There are points of diminishing returns in multiple ways: (assuming M110 spring, 1.35j which would be 382fps on a .20) If you are undervolumed, you may be shooting 1.35j with a .20, but find you shoot 1.2j on a .32 If you are overvolumed, you may be shooting 1.2j with a .20, and 1.35j with a .32 If you are grossly overvolumed, you may be shooting 1j with .20s and 1.2j with .32, but might also be at 1.35j with .43s There's a balance point where you can be pretty close across the board. For example, my M14 is within <.05j across a multitude of BB weights. It's a balancing act. So manufacturers generally state with their cylinders "for 300-400mm barrels" or "for 200-300mm barrels". You want to be on the top end, so if you have a 229mm barrel, you'll want a 200-300mm port. If you have a 285mm barrel, you'll want the 300-400mm port. There are no real standards in airsoft manufacturing, so the same cylinder port could have different ratings depending on who makes it. Although it seems they tend to be rated by .20s, which is why you want to be near the top end; overvolumed a bit. Now, all that being said, there's no reason for you to go from a 229mm to a 285mm barrel in the first place. You will not gain any accuracy, and you will gain exactly 56mm of range. In airsoft, the sole advantage to having a longer inner barrel is making it easier to achieve higher fps, and a 205mm barrel can do 3.2j with the right build. So just upgrade to a higher quality 229mm, and use a 200-300mm port, like a prometheus type D If you have any other questions on how stuff works, it's probably already covered in this: http://airsoftcanada.com/showthread.php?t=166583 Last edited by ThunderCactus; August 7th, 2018 at 12:47..