Interesting test with 0.2g and 0.25g BBs

Masada

you can take my MP5k for whatever tests ya need KD, can find me in the usuall place.,;)

kdouglas

i might, but i might just use it as an excuse to buy one to be honest, if tony get's a credit card machine in store ill be buying that and possibly something else nice after next pay day

Masada

well its just sitting on my wall feeling miserable for itself if ya wanna use it., im not gonna bother with upgrading it for a month or 2 since ive so much other stuff to keep me ocupied.,:)

kevteljeur

kdouglas wrote: »

i might, but i might just use it as an excuse to buy one to be honest, if tony get's a credit card machine in store ill be buying that and possibly something else nice after next pay day

As I've just found out, he does not! But since he probably knows you, you could work something out...

kdouglas

not yet, as far as i know he's working on it, banks are painfully slow at these things though

kevteljeur

What difference does barrel 'tightness' (perhaps a more technical way to phrase it might be, an AEG with tighter tolerances) make to how this works? My SL-8 has a barrel diameter of 6.08 (admittedly, it's a long barrel), and my G36C most likely has a diameter of 6.08; would this affect how the AEG interacts with the bbs at different weights?

Obviously I speak as one without his own chrono, and a decent space in which to try it out in. Something else I'm curious about is how the different weights and other factors affect the speed over distance and power fall-off. At distance, you can literally dodge bbs if you're paying attention, and I was thinking that this effect would increase with a heavier weight of bb; maybe there's an optimum weight of bb where accuracy and speed are balanced. Do heavier bbs maintain speed better than initially faster but lighter bbs?

kdouglas

there's a lot of articles out there on various things like that already, and it's a bit outside the scope of what i'm doing at the moment to assess all of them, but barrel tightness can increase fps, and also decrease fps, there's no real concise answer and basically every aeg differs

with regard to dodging BBs, it's all about fps really, the slower the BBs fly, the easier they are to "dodge"

kevteljeur

kdouglas wrote: »

there's a lot of articles out there on various things like that already, and it's a bit outside the scope of what i'm doing at the moment to assess all of them, but barrel tightness can increase fps, and also decrease fps, there's no real concise answer and basically every aeg differs

Fair enough, I'll look it up so. I was just curious about whether that affects the test results of what you're doing, but it sounds like you'd already factored that in. Obviously, I have a personal interest in that

kdouglas wrote: »

with regard to dodging BBs, it's all about fps really, the slower the BBs fly, the easier they are to "dodge"

Of course - but what I'm interested in, is do heavier bbs maintain their initial energy better than lighter bbs? 1J is 1J (as if boards.ie hasn't seen enough discussions to clarify that matter ) but after say 50 metres, is that still true? Might a lighter bb be tailing off faster due to having less mass (and also being more influenced by environmental factors: say, wind)? I know it's a bit off-topic and maybe it's a distraction to what you're getting at, but I imagine it's not unrelated to acceleration from a longer or shorter barrel...

kdouglas

kevteljeur wrote: »

Of course - but what I'm interested in, is do heavier bbs maintain their initial energy better than lighter bbs? 1J is 1J (as if boards.ie hasn't seen enough discussions to clarify that matter ) but after say 50 metres, is that still true? Might a lighter bb be tailing off faster due to having less mass (and also being more influenced by environmental factors: say, wind)? I know it's a bit off-topic and maybe it's a distraction to what you're getting at, but I imagine it's not unrelated to acceleration from a longer or shorter barrel...

http://arniesairsoft.co.uk/?filnavn=/articles/fps_dist_time/fps_dist_time.htm

That article will answer some of your questions, it's all theoretical, but it graphs the max effective range of .20g and .25g BBs. Of course if you can't be bothered reading the entire article, the summary is basically this:

Overall, the important results to us are as follows:

1. Shots made within 50 feet will have a greater ending velocity with .20 gram bbs.
2. Shots made over 50 feet should use .25 gram bbs for stability and velocity retention.
3. BB flight times under 0.25 of a second can use .20 gram bbs for a higher velocity.
4. BB flight times over 0.25 of a second should use .25 gram bbs because velocity and momentum is conserved better.
5. Shots fewer than 90 feet can use .20 gram bbs for a faster shot time.
6. Shots made over 90 feet should use .25 gram bbs for a quicker, more stable ammo flight path.

kevteljeur

kdouglas wrote: »

http://arniesairsoft.co.uk/?filnavn=/articles/fps_dist_time/fps_dist_time.htm

That article will answer some of your questions, it's all theoretical, but it graphs the max effective range of .20g and .25g BBs. Of course if you can't be bothered reading the entire article, the summary is basically this:

Aha - before I saw your response and link, I found this: http://www.airsoftretreat.com/features/articles/fpsweight/ - posted by the same geezer though. But it confirms what I thought (*pats self on back for astute cleverness*) and I think I might follow Vtec in getting .23s - Begadi has those in bio - because they have the mid-range compromise in terms of energy use. Very interesting that at longer ranges the .25 has the advantage, I'll be interested to see what you find if you get a chance to try out the heavier bbs in play. I'm sure that as with your initial energy test premise, that there is a cut-off.

Look forward to the results of your tests, anyhow, thank you for the answers and sorry for the distraction!

kdouglas

No worries.

I got some .30s today courtesy of Cheeky Monkey, so can do some good tests with them here at home against the .20s and .25s, I also just got a tracking number from begadi for the rest of my BBs, so hopefully they'll land during the week. Not sure when I'll get time to do all the tests, but as soon as I do, it'll be up.

Stercus Accidit

"30 shots fired, alternating between .25, and .2, starting with .2, thus giving it a slight bias due to cool down affecting the next shot more.

2 pistols, a WE 1911, known for its hard kick, a We luger, with less kick, thus more eficiency.

Over 30 shots, cool down brought down the highest energy from 0.75 to 0.6 joules.

It was noted, that .25s had .02 more joules per pair of shots, despite being the second shot fired in a pair.

It is my belief that this is due to a slower acceleration, thus staying in the barrel slightly longer, and absorbing more kinetic energy.

As per KD's results."



All results, bar fluke shots that were not read, or just were way off the trend.

15 shots per pistol, control shot, .2, .25, control shot, .2, .25, control shot, .2, .25 ....

The controls were to widen the gap between tests to increase cool down without being read as a result.

1911;
.20g bbs, energy in joules: .71 .7 .67 .64 .6
>25g bbs, energy in joules: .73 .72 .7 .65 .56*

* denotes last shot, low pressure in mag.


Luger (I love it )*
.20g bbs, energy in joules: .74 .71 .69 .68 .67
.25g bbs, energy in joules: .75 .73 -X- .68 .69

* has a few issues not mentioned before, I will post on them soon.

So it seems that .25's in a 4" and 5" barrel get approx .02 joules extra energy, when fired second mind suffering the cool down of the first bb,

so if this is worth a lower initial fps, I dunno.

kdouglas

I think it's best to try and avoid the cooldown effect completely, so I took shots with approx 5-10 seconds gap between them. I've got my range of BBs now to test, so as soon as I get some gas and clear an afternoon i'll get to testing them all in different gbbs and aegs to see the effects.

Masada

did ya get .3's KD? i have some if ya need for the test,.,


EDIT: i really should read the thread before posting.,:p

kdouglas

yup, .12, .16, .18, .20, .23, .25, .28, .30, .33, .43, .87

kevteljeur

vtec wrote: »

did ya get .3's KD? i have some if ya need for the test,.,


EDIT: i really should read the thread before posting.,:p

Have you played with those in the field? Are you able to hit targets past 10 metres?

kdouglas wrote: »

yup, .12, .16, .18, .20, .23, .25, .28, .30, .33, .43, .87

Begadi delivered, huh? Excellent. Looking forward to getting bbs from them in the next few days too. Have you tested your theories with all those sizes yet?

kdouglas

not yet, a) because i haven't had time and b) because i've currently no gas

It'll probably be the week after the gathering when I get a chance to do the full test.

Masada

you gaming tomorrow KD? ive 2 bottles of gas in mt bag so you can take one of them.,


Kev: nope i havent used them yet, im gonna give them a go tomorrow and see whats the story with them, should be interesting.,

kdouglas

vtec: might drop out for a while with the psg1, cheers for the offer, need to swing by and get some gas anyway