Do you think getting shot with lighter BBs from an an upgraded gun would hurt more, less, or the same?

[Hectic]

This may prove usefull.


http://ninjase.viscidity.com/trypsin/airsoftcalc/

This tells me that a .12g BB @ Around 580FPS has around the same energy as a .43g BB @ Around 306FPS

so less weight @ same speed = less energy

but in all fairness with are field limits do these really hurt all that bad (spare getting one on bare skin or a tooth at close range)

[DonP]

Originally Posted by MadMax

I'm thinking we need a hybrid target that behaves in a Newtonian manner with an unpenetrated skin (like your cloth outer). Maybe a foam target that isn't resiliant with a cloth outer might be a good target. It would exhibit low rate dependent behavior and still provide a permanent deformation to assess. Maybe put a canvas cloth on that green sponge that flowers get stuck into.

That's not a bad idea, I might try picking some up next time I'm at the 1$ store.

My favorite idea for a follow-up is human trials, though. Get shot with a .25 and a .12 from the same gun in either thigh (for example) and judge how much it subjectively hurts. Maybe also document the bruise severity as well the next day. While pain is of course subjective, I think it would be hard to refute such results since they are pretty much a test of exactly what we're after.

Originally Posted by Drake

@Don: you could make some airsoft-caliber ballistics gel with some kitchen grade gelatin

A messy proposition, but the shattered gelatin and highly visual nature of the hit result would be pretty cool. Shooting stuff that "does" something when hit is fun...

[DonP]

I did a couple more tests with that floral foam crap. Messy as hell.

The idea is to see if the different medium shows the same results. MadMax pointed out that many puttys are non-newtonian, something which didn't occur to me and was bugging me.

A few changes made:

1. Fired at 6" away instead of 2m
2. Foam has BDU material over it.
3. Still used .12, .20, .28 and .43 BBs. But this time only from the 1911 GBB on Duster and an APS2 bolt-action.
4. I tried a pure penetration test between .12g and .43g from an APS2 into the foam with no BDU over it. Just for fun.

Short story: Same results trend observed (the heavier the ammo, the harder the impact and deeper the penetration when fired from the same gun.)

It was interesting! Some lessons learned:

- Have a vacuum handy. It's messy.
- Vacuum also helps suck out the debris from the holes so you can see better.
- Not nearly as easy to measure this stuff with a depth gauge since it's so frangible/light/fragile. I gave up trying and just had to eyeball it.
- Shooting stuff is fun.

1911 on Duster from 6" away

Clear progression of wider/deeper/messier impact the heavier the BB gets. The BDU material is noticeably "dirtier" with foam-bits as the BBs get heavier.

APS2 from 6" away

Same observations as above, but more pronounced.

Penetration test: APS2 firing .12g and .43g into bare foam from 6" away. Pictures are self-explanatory.








The .43g penetrated more than the .12g, but the difference was not as big as I thought it would have been. Hmmm!

[FOX_111]

Nice test.
What kind of foam is that?

I think we should move on to human test now. (o:

[DonP]

EDIT: It's floral arrangement foam.

Something just occurred to me -- I used the fishing line to cut up the APS2 result foam to bisect each impact crater!

Neat (and odd) that the difference between .12g and .20g is bigger than the difference between .20g and .28g, even though they are both .08g apart from one another.

You don't see it so much from this angle, but the width increase of the crater I think is more noticeable as you go .20 -> .28 -> .43 but the increased depth of penetration is harder to see.

[MadMax]

Wow, excellent test. I think that clinches it for me. 0.12g pellets have significantly less damage potential than heavier ones.

However it does look like the 0.2g, 0.28g have nearly comparable damage potential to the 0.43g pellet which is a huge lot heavier. Are all those shots chronying in at equivalent energy? I'm wondering if the dinky 0.12g pellets are coming out with significantly less energy than the heavier ones indicating some sort of weight based limit where lighter pellets are not able to take on as much energy as heavier ones.

[Flatlander]

Now I'm curious to see how you can relate this to pain. FYI, the JOC club out of Calgary has a dedicated indoor facility and play a lot of CQB; they are required to use a MINIMUM of .20g BB's (.12's NOT allowed). I *believe* this is for pain reasons, but I'm not entirely sure. Maybe one them will chime in.

[Dracheous]

Originally Posted by MadMax

Wow, excellent test. I think that clinches it for me. 0.12g pellets have significantly less damage potential than heavier ones.

However it does look like the 0.2g, 0.28g have nearly comparable damage potential to the 0.43g pellet which is a huge lot heavier. Are all those shots chronying in at equivalent energy? I'm wondering if the dinky 0.12g pellets are coming out with significantly less energy than the heavier ones indicating some sort of weight based limit where lighter pellets are not able to take on as much energy as heavier ones.

I think its more to do with the weight/speed curve that I was taking about earlier. The .43 does have more damage and slightly deeper craters than the .28, but for the .15g difference it is fun to see that my idea/theory that the reduction in speed due to the heavier weight does limit the addition of impact energy to the heavier rounds. I would be VERY interested to see this SAME test done at 10ft 20ft and 30ft ranges . To see if my theory that the farther the round gets the heavier ones are going to loose that impact energy sooner than the lighter rounds due to loss of speed. Though I suspect you would see the .28 and .43 catch up neck to neck at around the 50ft mark to have the same impact.

I am curious if there is an indication of the density of this foam that you are using, so that I can hit the local hobby supply shop and pick up some of the same stuff.

[Skladfin]

Originally Posted by Dracheous

I think its more to do with the weight/speed curve that I was taking about earlier. The .43 does have more damage and slightly deeper craters than the .28, but for the .15g difference it is fun to see that my idea/theory that the reduction in speed due to the heavier weight does limit the addition of impact energy to the heavier rounds. I would be VERY interested to see this SAME test done at 10ft 20ft and 30ft ranges . To see if my theory that the farther the round gets the heavier ones are going to loose that impact energy sooner than the lighter rounds due to loss of speed. Though I suspect you would see the .28 and .43 catch up neck to neck at around the 50ft mark to have the same impact.

I am curious if there is an indication of the density of this foam that you are using, so that I can hit the local hobby supply shop and pick up some of the same stuff.

loss of speed is not loss of energy

[newcomer]

Originally Posted by Flatlander

Check your units. You're off by a factor of 1000 (convert grams to kg???)

MadMax,

Have you seen this before: http://cybersloth.org/airsoft/trajectory/index.htm

I'm curious to get your take on it coming from another engineer.

Is it just me or what but the link is dead. I could view it on cached version but then most of the pics wouldn't load. Anyone knows?

[Styrak]

Originally Posted by Skladfin

loss of speed is not loss of energy

Speed (along with mass) is directly proportional to energy imparted.

Think a bus hitting you at 1km/h is the same as 50 km/h?

E = 0.5[m][v^2]

Velocity actually changes energy of an object more than mass.

[Scarecrow]

The only thing I was thinking is simply conditions and applications. A lot of guys use .20's for indoor winter gaming, simply because of the environment - no wind conditions, clear line of shot, inexpensive ammunition, etc.

I suspect that in indoor CQB environments using .20 and getting hit closer could hurt more than being hit by a .28 in an outdoor environment, simply from contact distances - ie: CQB tending to be closer.

Just anecdotally, I`ve been hit in the pinky (my least favorite place to take a shot) with .20 and .28 at about 15 feet, and I can say without a doubt the .28 had me hopping around and swearing like a mofo, whereas the .20 just stung. From that experience I`ve always thought heavier=hurtier.

Interesting thread, and kudo`s DonP, those are really creative testing methods.

[newcomer]

Anyone knows what happened to cybersloth or the guy? I have just spent 8hrs reading and trying to understand the articles and I'm still only halfway through! Lots of useful info based on solid physics but a shame I couldn't read most of the graphs.

[Auhydride]

I think it's the 0.4g BBs storing more energy than the 0.12g ones, even though springs store the same amount of energy, the shape of the bbs, lack of air seal in the barrel, these all effect physics

[bean]

I think it would be interesting to do the test with bb's from the same manufacturer to see if tolerances have a huge effect on the damage done. I say this because if you look at a bb like excel they have a much lower diameter then a normal bb which is why they are suggested when people have jamming issues. I also wonder how much hopup has an effect on these results. Even with the hopup fully off it still touches the round.