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Old September 24th, 2012, 07:11   #36
A Total Bastard
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Join Date: Jun 2005
Location: Consecon, Ontario
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Originally Posted by invisiblehand View Post
Have you considered adding smoke to see the movement of the air? While this isn't directly related to the hopup, it would help to show if the BB is being held off the walls of the barrel by the air cushion?
Interesting angle we had not thought about. Wouldn't do much in the barrel but it might show the turbulence and any associated patters at the muzzle.

Originally Posted by Cpt- Lovegrove View Post
i hope you plan on releasing a video of the tests especialy of the highspeed shots, i would love to see them
We will be release a paper in PDF format and doing a complete video review of all our work, from the build through to any tests we run.

Originally Posted by ThunderCactus View Post
Like I've said before, there's a maximum range and accuracy that can be achieved with a given weight of BB
Once you've topped out the performance capability of the BB, nothing you do to the gun is ever going to make that BB fly further or straighter.

So with any BB your optimal relative velocity is around 320-350fps, any faster and it destabilizes too quickly, any slower and you're just not getting the most out of it.
Once you hammer out barrel, volume, and compression requirements, the only thing left is barrel length. It's just a question of at what point does the BB stabilize itself within the barrel. For GBBRs and pistols, that's about 80mm or so, much more difficult to tweak with GBBRs since longer barrels tend to raise fps, which requires heavier ammo, which in turn raises the muzzle velocity even more.
AEG's tend to stabilize perfectly around the 420mm mark. Any barrel beyond the point of stabilizing is just useless metal. It's allowing more time for the BB to be DE-stabilized by potential fouling in that barrel.
Two VSR-10s built exactly the same internally, one with a 650mm barrel and one with a 420mm barrel, both shooting .3s, or one at 380 and one at 470, or 470 with .36s vs 440 with .3s, doesn't matter what combo we use, the 420mm barrel was never bested by the 650mm in terms of accuracy.
In fact, the 650mm barrel had worse accuracy when using .3s at 470fps

The idea that longer barrels increase accuracy in airsoft was carried over from real steel, but the physics of the two are completely different.
100% agree.

Stalkers work also indicates roughly the same results. We also have three "wide bore" barrels to test as that seems to be the cool new direction as of late.

Originally Posted by Dynamo View Post
a clear twist barrel.. really?
i don't think BBB would have the $$$ to shell out to make a rifled acrylic barrel. just a simple smooth bore is going to be expensive enough.
Indeed. The "barrels" we are using are precision bore Pyrex labglass. Inner bore accurate to .0005 of an inch. We are going to have to properly crown them and see if they will fit into exiting hop ups, so prep time may take as long as a few weeks. Nothing custom made and these were not cheap.

Last edited by Blackthorne; September 24th, 2012 at 07:16..
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