Airsoft Canada
AirsoftParts.ca

Go Back   Airsoft Canada > Information Center > Newbie Tank
Home Forums Register Gallery FAQ Calendar
Retailers Community News/Info International Retailers IRC Today's Posts

how to chrono a GBBR?

:

Newbie Tank

Reply
 
Thread Tools Search this Thread
Old August 13th, 2010, 19:56   #1
Dart
 
Dart's Avatar
 
Join Date: Apr 2009
Location: Grande Prairie Alberta
how to chrono a GBBR?

Hey I got a quick question.
When at a field and its time to chrono guns, how do you guys chrono in your GBBRs.

With a GBBR I have read alot of places that a heavier round can actually up the FPS if not keep it the same as the lighter round as its in the barrel longer to allow the gases to expand behind it. So do you use .20s? or do you use what you will be playing with.... or do you calculate in energy?
Dart is offline   Reply With Quote
Old August 13th, 2010, 19:57   #2
ex
IRON TESTICLES
 
ex's Avatar
 
Join Date: Aug 2005
Location: Ottawa
GBBR's are chronied the exact same as AEG's.

I am not sure how a heavier round can make the FPS go up though. that does not sound logical.
__________________
ΜΟΛΩΝ ΛΑΒΕ

Last edited by ex; August 13th, 2010 at 19:59..
ex is offline   Reply With Quote
Old August 13th, 2010, 20:08   #3
Styrak
 
Styrak's Avatar
 
Join Date: Jan 2007
Location: Saskatoon, SK
Send a message via MSN to Styrak
Chrono with 0.20's, same as AEG's.

But yes GBB's have a different effect when moving up in BB weight.
They retain more energy because of the gas expansion and having more time in the barrel to use that pressure.

For example when I had a KJW P229 (which has a really short barrel) it would chrony 270-280 with 0.20's and 260 with 0.28's.
If you did the same thing with an AEG it would go down about 60fps to 210-220 or so.
__________________

Airsoft Sales and Repair/Upgrade Services
Styrak is offline   Reply With Quote
Old August 13th, 2010, 20:29   #4
AngelusNex
formerly Sepulcrum
 
AngelusNex's Avatar
 
Join Date: May 2007
Location: Kingston,ON, aka Funkasia
Send a message via MSN to AngelusNex
Quote:
Originally Posted by Styrak View Post
Chrono with 0.20's, same as AEG's.

But yes GBB's have a different effect when moving up in BB weight.
They retain more velocity and increase in energy slightly because of the gas expansion and having more time in the barrel to use that pressure.
Fixed that for you to reduce confusion.

It's all due to the compressed gases expanding. heavier bb = more time in barrel (initially slower) for the gas to expand and fully release it's energy.

But yes, most fields measure it the exact same way as AEGs, though some host may do a joule calculation if they take the expansion effect on heavier bbs into account. Though I doubt, at least for M4 or shorter length barrels, it will have too drastic an effect, may be wrong on that though.

Last edited by AngelusNex; August 13th, 2010 at 20:33..
AngelusNex is offline   Reply With Quote
Old August 13th, 2010, 20:57   #5
Amos
 
Amos's Avatar
 
Join Date: Aug 2006
Location: Tokushima, Japan
Send a message via MSN to Amos
get a good chrono, it should be able to measure in joules, set it to what weight you want to fire, fire with the weight you're gonna be using and see what the Joule rating is.
__________________
Custom Builds:
FA3674U
Krinkov
G3SD6
Amos is offline   Reply With Quote
Old August 13th, 2010, 21:36   #6
Dart
 
Dart's Avatar
 
Join Date: Apr 2009
Location: Grande Prairie Alberta
yah I tried the tac shops out here. says my rifle is firing at 2.49J.... thats DMR/sniper territory. I measured with .25g and set it to .25g on the thingy....

So I guess its npas time eh? lol.
Dart is offline   Reply With Quote
Old August 13th, 2010, 23:05   #7
Amos
 
Amos's Avatar
 
Join Date: Aug 2006
Location: Tokushima, Japan
Send a message via MSN to Amos
lol that's 518 FPS on a .20.. Unless your club's cool with that... Npas time!
__________________
Custom Builds:
FA3674U
Krinkov
G3SD6
Amos is offline   Reply With Quote
Old August 13th, 2010, 23:21   #8
ShelledPants
 
ShelledPants's Avatar
 
Join Date: Feb 2008
Location: Toronto, On
Quote:
Originally Posted by Amos View Post
lol that's 518 FPS on a .20.. Unless your club's cool with that... Npas time!
The Gen2 Wetti M4's shot around 600fps out of the box... and (without knowing this at the time) we shot a buddy in the ass from 15 feet away with a .28.

It dented his jeans. :\
__________________


r skal rsa, s er annars vill
f ea fjr hafa. Sjaldan liggjandi lfur
lr um getur n sofandi maur sigur.
ShelledPants is offline   Reply With Quote
Old August 13th, 2010, 23:55   #9
Dart
 
Dart's Avatar
 
Join Date: Apr 2009
Location: Grande Prairie Alberta
yah its about 460 fps on .25, 140m/s I think is what it said I can't remember. our sniper limit is 550fps so I do fit under the bar there. I have my mac11 for close range or my hi capa.

Still trying to figure out the stupid bolt lock issue.
Dart is offline   Reply With Quote
Old August 14th, 2010, 16:05   #10
ThunderCactus
Not Eye Safe
 
ThunderCactus's Avatar
 
Join Date: Feb 2007
Location: Calgary...now with less oil industry than eco-hipster Vancouver
Well although the theory behind heavier ammo = more joules works, and it does make a difference, the difference is like a mere 10 fps
I chrono'd a WE M16 on .20s and .30s, and the difference between the joules of force equated out to around 10fps on .20s
The biggest factor for GBBR is the heat, they shoot harder when they warm up
__________________
Tamiya connectors suck.
Quote:
Originally Posted by swatt13 View Post
i never understood why the oil refinery had a brothel... i never see them at the refineries i work at this is bull!
ThunderCactus is offline   Reply With Quote
ReplyTop


Go Back   Airsoft Canada > Information Center > Newbie Tank

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Airsoft Canada
AirsoftParts.ca

All times are GMT -4. The time now is 02:34.


Powered by vBulletin® Version 3.8.10
Copyright ©2000 - 2017, vBulletin Solutions, Inc.