Jump to content


Optimum Barrel Length


  • Please log in to reply
19 replies to this topic

#1 holderp

holderp

    Enthusiast

  • Members
  • PipPip
  • 48 posts
  • Gender:Male
  • Location:Winston Salem, NC
  • Country:

Posted 15 April 2014 - 07:59 AM

For a .5 cylinder what would be the optimum barrel length?

#2 gcw360

gcw360

    Supreme Guru

  • Super Moderator
  • PipPipPipPip
  • 11,547 posts
  • Gender:Male
  • Location:New Jersey
  • Interests:Airsoft (Especially repair and customizing), Fly Fishing, Fossils (Especially Dino), Snakes, Photography
  • Country:

Posted 15 April 2014 - 01:15 PM

View Postholderp, on 15 April 2014 - 07:59 AM, said:

For a .5 cylinder what would be the optimum barrel length?
I've been told 425mm (SR10 length).  Though I use it in my 394MM and it works fine in the 509mm.

#3 vanevery

vanevery

    Specialist

  • Members
  • PipPipPip
  • 981 posts
  • Gender:Male
  • Country:

Posted 15 April 2014 - 02:29 PM

That is a good question.

I honestly believe through my own years in working on airsoft guns and listening to others on the subject of Air Volume Relationship, that we need a start over from scratch approach to today's common knowledge on the subject. We need to look at this all over again and go back to the drawing board.

To answer you question specifically, the best barrel I have ever used with the KWA
Type1 (.5) Cylinder has been a 455mm Inner Barrel. It may in fact be that the 425mm is better.
Most of my experience with the KWA 425mm Inner Barrel has been with Full/Type-0 Cylinders. So, I do not have enough direct comparison testing experience to say which is better.

This I believe I can say for sure.
A 425mm and a 455mm will both out-perform the 395mm and 509mm Inner Barrel with a KWA Type1 (.5) Cylinder.

Edited by vanevery, 15 April 2014 - 02:30 PM.


#4 holderp

holderp

    Enthusiast

  • Members
  • PipPip
  • 48 posts
  • Gender:Male
  • Location:Winston Salem, NC
  • Country:

Posted 15 April 2014 - 03:49 PM

Thank you both.

Vanevery is this you?
http://ncairsoft.org...ressor-Question

#5 vanevery

vanevery

    Specialist

  • Members
  • PipPipPip
  • 981 posts
  • Gender:Male
  • Country:

Posted 15 April 2014 - 06:02 PM

View Postholderp, on 15 April 2014 - 03:49 PM, said:

Thank you both.

Vanevery is this you?
http://ncairsoft.org...ressor-Question
That would be yours truly. Are you Turner?

#6 holderp

holderp

    Enthusiast

  • Members
  • PipPip
  • 48 posts
  • Gender:Male
  • Location:Winston Salem, NC
  • Country:

Posted 16 April 2014 - 02:25 AM

No holderp over there too. I don't post over there much. Just lurk mostly.

Do you go to Fulda Gap

#7 vanevery

vanevery

    Specialist

  • Members
  • PipPipPip
  • 981 posts
  • Gender:Male
  • Country:

Posted 17 April 2014 - 01:31 PM

View Postholderp, on 16 April 2014 - 02:25 AM, said:

No holderp over there too. I don't post over there much. Just lurk mostly.

Do you go to Fulda Gap
I thought your Forum Handle sounded familiar.

Fulda Gap.
Yes, I have been to many Fulda Gaps and many other events held at CDWC.
I have been to more games at CDWC than any other field.
Great Field.
How about you?

#8 holderp

holderp

    Enthusiast

  • Members
  • PipPip
  • 48 posts
  • Gender:Male
  • Location:Winston Salem, NC
  • Country:

Posted 17 April 2014 - 05:14 PM

I was at Fulda back when it's was only 400 people there and NATO won. That was my first AS game. I guess this past year was my 4th. This past year we spent two days fighting for Apache. If we can keep NATO out of the parking lot this year maybe we can win again.

Up until this year we (me my son his best friend and his dad) only played AS once a year at Fulda. We are hoping to play more this year. Played at AS R US's field in Burlington a few weeks ago.  1st game with the new CQR.

#9 vanevery

vanevery

    Specialist

  • Members
  • PipPipPip
  • 981 posts
  • Gender:Male
  • Country:

Posted 17 April 2014 - 06:21 PM

View Postholderp, on 17 April 2014 - 05:14 PM, said:

I was at Fulda back when it's was only 400 people there and NATO won. That was my first AS game. I guess this past year was my 4th. This past year we spent two days fighting for Apache. If we can keep NATO out of the parking lot this year maybe we can win again.

Up until this year we (me my son his best friend and his dad) only played AS once a year at Fulda. We are hoping to play more this year. Played at AS R US's field in Burlington a few weeks ago.  1st game with the new CQR.
Fulda:
Last year was incredibly tough.
NATO seemed to be stacked with noobs, vacationers, first time ever at the field players, only a few experienced teams, and a first time General.
WARSAW was stacked with mostly LEO teams, active and former Military teams, and a leadership group that has been together for four years.
I was there both days in NATO Sniper Unit. We did well as a Unit in terms of performance, but 8 guys can only do so much.
Most of NATO forces were in the parking lot most of the time.

Aisoft R Us:
I know Zach Chavez, the manager of the store.
We met last year at Fulda for a brief moment, but have had many conversations on the phone and in PM's.
I have not been to their field, but I do intend to.
PBC Greensboro is near there.
If you have not been, I highly suggest going.
It is a great field.

I will be getting out more for airsoft this summer.
Let me know what games you go to and maybe we can meet and possibly run together for a game.

#10 holderp

holderp

    Enthusiast

  • Members
  • PipPip
  • 48 posts
  • Gender:Male
  • Location:Winston Salem, NC
  • Country:

Posted 17 April 2014 - 06:39 PM

I've spoken with Zach a few times. They just bought a new lot for a field. Work In Progress. AIRSOFT R US is a good shop and has the potential to be great. They seem to moving away from KWA. I miss Airsoft Caolina.

I'll let you know when we play next.

#11 Chuck S

Chuck S

    Guru

  • Members
  • PipPipPipPip
  • 1,287 posts
  • Gender:Male
  • Location:Cleveland, Ohio
  • Country:

Posted 18 April 2014 - 11:20 AM

Does anyone have a reference to the volume if the various cylinders?  Seems the cylinder volume has to be big enough to expel the air in the barrel along with the BB behind that air.  I can't intuitively see why "too much" air would cause any problems.

-- Chuck

#12 holderp

holderp

    Enthusiast

  • Members
  • PipPip
  • 48 posts
  • Gender:Male
  • Location:Winston Salem, NC
  • Country:

Posted 19 April 2014 - 05:51 AM

I can't seem to find one. As far as there being too much air it seems that too much can be bad if the bb exits before the piston has had time to fully excelerate.

#13 Chuck S

Chuck S

    Guru

  • Members
  • PipPipPipPip
  • 1,287 posts
  • Gender:Male
  • Location:Cleveland, Ohio
  • Country:

Posted 19 April 2014 - 03:32 PM

I need an explanation.  :)  Seriously.  I'm trying to understand this.

-- Chuck

#14 holderp

holderp

    Enthusiast

  • Members
  • PipPip
  • 48 posts
  • Gender:Male
  • Location:Winston Salem, NC
  • Country:

Posted 19 April 2014 - 07:25 PM

http://www.airsoftca...ad.php?t=112634

#15 Chuck S

Chuck S

    Guru

  • Members
  • PipPipPipPip
  • 1,287 posts
  • Gender:Male
  • Location:Cleveland, Ohio
  • Country:

Posted 20 April 2014 - 03:02 AM

Thanks.  Couldn't find anything describing why too large a cylinder -- too much air -- detracts from performance.  Like too much gunpowder I can see that the extra can be wasted (in the case of gunpowder it'll be unburned) and not accomplish anything. I'm still puzzled.

-- Chuck

#16 gcw360

gcw360

    Supreme Guru

  • Super Moderator
  • PipPipPipPip
  • 11,547 posts
  • Gender:Male
  • Location:New Jersey
  • Interests:Airsoft (Especially repair and customizing), Fly Fishing, Fossils (Especially Dino), Snakes, Photography
  • Country:

Posted 20 April 2014 - 06:19 AM

Let me know if this helps.  Let's not worry about calculations shall we and lets talk in general terms.
  • The piston starts at rest all the way at the back of the cylinder
  • As the piston accelerates, it pushes a fixed volume of air (x), which is determined by where the port is on the cylinder
  • The BB begins to travel down the barrel and requires a volume of (y) to exit the barrel
  • As soon as enough air is pushed out of the cylinder, the BB exits the barrel
    • Note: The speed of the piston as the BB exits the barrel determines the BB's velocity. This is a rough estimate based on the fact that the air inside the barrel is compressible....but for our purposes it's fine
  • Now, if you have more volume of air in the cylinder than is needed, lets say 2y (2 times y) then the BB will exit when the piston is half way through the cycle, and still accelerating and the velocity of the BB is decreased.  Case in point, ) type cylinder in a short barrels gun
The dynamics are a bit different for a gun with too short a cylinder and a long barrel but results are similar.  Airsoft manufacturers, and techs who know what they are doing, use cylinder sizing to adjust FPS while maintaining proper spring tension to mitigate over-spin and pre-emgagment of the piston.

Hope this helps a bit.

#17 holderp

holderp

    Enthusiast

  • Members
  • PipPip
  • 48 posts
  • Gender:Male
  • Location:Winston Salem, NC
  • Country:

Posted 22 April 2014 - 07:52 AM

I am thinking I can buy an sr10 425 mm stock inner barrel and the short piece of the outer barrel from a CQR MOD 2, part 299-2, from the proshop and install in my Mod1. Thinking this may be a cheap way to get the longer inner and extend the outer to cover the inner without having to pay$50 for a mock [barrel extension].
Thoughts

#18 BLATEY

BLATEY

    Enthusiast

  • Members
  • PipPip
  • 174 posts
  • Gender:Male
  • Location:Iowa City, Iowa
  • Interests:Keepin' it Real.
  • Country:

Posted 22 April 2014 - 08:21 AM

You will need another 30mm of extra barrel length even after the mod 1 extended out barrel part, I believe it's only 395 after you convert it to a mod 1 length wich would mean you need a mock suppressor.

Or do you mean add an extension on to your mod 1?

#19 holderp

holderp

    Enthusiast

  • Members
  • PipPip
  • 48 posts
  • Gender:Male
  • Location:Winston Salem, NC
  • Country:

Posted 22 April 2014 - 08:23 AM

Add the extension to the mod1. So after the front sight I would have the mod1 and mod2 extensions.

#20 BLATEY

BLATEY

    Enthusiast

  • Members
  • PipPip
  • 174 posts
  • Gender:Male
  • Location:Iowa City, Iowa
  • Interests:Keepin' it Real.
  • Country:

Posted 22 April 2014 - 11:57 AM

Ok, gotcha. At first I thought you were saying you were putting the mod 1 extension one the mod 2 which didn't make sense but I read over it again and I believe it should work.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users