Clear Barrel Experiments
 

As some of you know BB Bastard is doing some R&D this year to try and shed some more light on how the BB behaves in the barrel under different hop up conditions.

We are now finalizing the build for this test rig, and have the Pyrex barrels inbound from the US to be custom machined here.

we will be posting our findings here as well as on Arnies and Airsoft Mechanics.

Here is the link to our project on Indiegogo, http://www.indiegogo.com/airsoftmyth
Any support is appreciated, both words and financial!

We are not engineers and I am asking for the same support I have requested at Airsoft mechanics:

1. Contructive criticizim is fine, if you are going to bash a grass roots experiment becuase we can't afford to have Mythbusters on contract to figure this out for us, get your troll on somewhere else.
2. Please keep this thread on topic
3. If you see us doing something that will ruin the results PLEASE LET US KNOW :D

We are looking to answer a few basic questions:

1. does the BB touch the inside of the barrel in transit
2. How does hop affect the behavour
3. how do different hop ups affect the behavior in the barrel

Wish us luck!

will you be using different brands of hopups/hopup units?
if not will the whole unit be clear?
will you be using different(most common) gearboxes/variations of parts?

Will you be testing with AEG, GBBR, and PTW? I think this is great you guys are doing this. BB bastard is number one as far as SWATT is concerned. Please give us detailed results on barrel bore sizes, hop-up types (bucking sizes), FPS, and BB weights you use. If you guys nail down some good results, you could build a custom Bastard labs gun (Systema please!). Lol, just kidding.

Also, how close are you guys to developing a 0.30g and 0.36g bio round?

Yes are going to try and test at least 5, but we have to see how machining the Pryrex goes

We are using a metal mechbox

No. Air is air, we are only looking at barrel and what happens in the barrel. having said that, we do intend to use different springs and nozzles to see what effects they have on the BB.

We are building a dedicated test rig. As I mentioned above, we are only looking for BB behavior in the barrel, so from the nozzle out we will be trying different things. We will only be using one mechbox and gearset at this time to keep things as predicable as possible.

Also, how close are you guys to developing a 0.30g and 0.36g bio round?[/QUOTE]

Close. we are talking to our new manufacturers currently and getting test run sample in. It takes time to do the tweaking.

How did you plan on studying the behaviour of the BB? Highspeed camera with a strobascope I hope.

http://en.wikipedia.org/wiki/Stroboscope

Am SO looking forward to this!!!

Yes indeed. We are going to be starting an Indigogo project to help cover the rental costs of the camera in the next few days. We will be giving funding credit, research credit on the final report and t shirts for donations.

Running between 10,000 and 45,000 frames per second monochrome. We will be using the camera alone to see flight path inside the statically lit barrel and a strobascope.

it's going to be interesting to see how you are going to capture the BBs traveling down the barrel. a glass/plastic/transparent cylinder will have ridiculous amount of refraction, that would distort the image of the BB. it would make it really hard to see where the inner walls of the barrel are. i think the best way to see if the BBs contact the barrel inner surface is to use a high-speed camera right in the BBs path. have the barrel/BB back lit so you only see the BBs silhouette. another option would be to have the camera side of the barrel machined into a concave shape to reduce the distortion from refraction.

Pyrex has different light transmission properties than most materials but it is still going to be a challenge. We are working on a few different ideas, including having the barrel suspended in distilled water and having reference lines for the inside of the barrel on a background.

Once you figure out how the BB reacts, are you going to be testing barrel lengths?
Practical field testing has shown me that 380-420mm barrels are just about optimal, anything longer tends to be useless extra barrel, and anything shorter tends to affect accuracy.

We have 12 barrels coming in ranging from 19 to 21 inches, and 4 different bore sizes.

Unfortunately due to costs we had to pick a happy medium of off the shelf parts, but we are looking to get more detailed and customized equipment from the crowd sourced funding (Indiegogo)

Subscribed.

Are you going to colour the BB in some way to monitor the spin of the BB in the barrel? Or just study the "touching" between BB and the barrel?

Obviously you're aiming to catch the bounces in flight vs. examining evidence of a bounce post shot.

I'd start with the later.

In a good setup my bet is 2 bounces...first right after the hopup nub...the second close afterwards and then I'm guessing it's stabilized and/or doesn't get a third bounce before it's gone from the barrel.

You could cheat and coat the inner surface of the barrel with a thin flim (say Molybendum)...then shoot a bunch of shots and look for discolouration patterns (it'll turn more silver as it's impacted). You could also capture BB's after the shot and if they had black marks on them then they've hit the barrel somewhere.

You don't even need a clear barrel to see that...just don't get any on your hopup rubber. I'd see coating the entire barrel...then cleaning the first inch of it (or just past the hopup cutout)...then assemble, clamp you gun in a vise and shoot. You can get powdered Moly at shooting places.

I'd stay simple and just setup for one set of tests....one standard barrel length (say 363mm) with 0.20's @ 350fps. Detail and publish the test setup and results and put it out there for peer review. Filter through the reviews and adjust testing from there.

Best of luck with this.

Very interested to see the results of this. It would end the age-long debate on whether tighter barrels actually cause the BB to bounce along the walls more, and if that affects trajectory.