BB weight vs. fps drop *rough* testing

[shifty51]

I haven't play as long as alot of you guys, but from what i've seen/imagine a .2g round would travel further, but in the wild a .25 would actually find its mark right? Due to bush penetration?

[CDN_Stalker]

**Irregardless of the range issue, these tests were done to provide data for a sniper rifle with certain upgrades, a certain spring for fps differences in between BB weights. This testing does not talk about range at all, just the differences seen with a consistant gun shooting various weights in a controlled environment**

Now, regarding range vs. weight, two things that nullify the entire range argument are as follows:

Maximum Range:

Where the BB eventually lands, doesn't matter where you aim, it goes where it goes based upon velocity, air density, any wind or vortices along it's path.

Effective Range:

The farthest possible distance your BB stays within the area of where you aim, say within 4ft maximum.

Heavier BBs will have a longer effective range that lighter BBs. Lighter BBs will have a farther maximum range than heavier BBs. Effective range of heavier BBs plus stability plus brush penetration is the key to BB choice.

Have said before, I have an MP5 with a Prometheus 110SP spring in it, shoot 365fps with 0.20g BBs, I can get 0.28g BBs past 200ft easily, and at about a 4ft spread at that distance. Good enough to hit a guy? Yup! Using 0.20g BBs, didn't try it at that point, but had a year's worth of experinece shooting only 0.20g, effective range of them from a 350fps gun is about 120-130ft maximum before they float off somewhere else other than where you aimed. Nuff said.

BTW, I among others enjoy arguing fact vs. physics, always fun when strong math skills prove lighter has farther range, and the way they try to explain why heavier goes farther and more accurately when they actually see it done with a moderately upgraded gun.

[shifty51]

Thanks thats my question answered. I think this should probably stickied. I am also interested to see if anyone has done an 'effective' range test with different weights/brands

[CDN_Stalker]

There actually was one, I forget where it's hosted at now, but it was using a stock G36 vs. an upgraded M16 at a range out to I think 130ft, and using a chrony with diffusers mounted. Ammo used was 0.20g, 0.25g and 0.30g, and of all rounds fired at the area used as a target, the highest majority of rounds entering that area were from the 0.30g BBs. Been a while since i saw it, but it proves that greater accuracy at longer ranges comes from heavier BBs since lighter tends to float off it's trajectory easier than heavier does.

Here's somethign else I posted a couple months ago, might as well link it with this thread for shits & giggles:

http://www.airsoftcanada.com/showthr...ght=ballistics

[Wilson]

So we can safely say that using a heavier BB, coupled with some modifications that would normally make an AEG skyrocket over the safe 400fps mark, is the best bet?

Accuracy appears to come from the heavier BB, so the .43 listed would be the best, and just use upgraded springs and internals to compensate for the loss of velocity - and then never, ever, ever load it with anything lighter for safety reasons.

[BBS]

Originally Posted by Wilson

So we can safely say that using a heavier BB, coupled with some modifications that would normally make an AEG skyrocket over the safe 400fps mark, is the best bet?

Accuracy appears to come from the heavier BB, so the .43 listed would be the best, and just use upgraded springs and internals to compensate for the loss of velocity - and then never, ever, ever load it with anything lighter for safety reasons.

i'm pretty sure using heavier BBs like .43 will cause more stress on your gearbox. Remember to clean off the silver coating on these BBs as it will mess up your hop-up.

maybe try using a .36g for your set up if you want a good compromise of velocity, accuracy, penetration, reliability, and range.

[Wilson]

Originally Posted by BBS

i'm pretty sure using heavier BBs like .43 will cause more stress on your gearbox. Remember to clean off the silver coating on these BBs as it will mess up your hop-up.

maybe try using a .36g for your set up if you want a good compromise of velocity, accuracy, penetration, reliability, and range.

Do you have those in stock?

[Dracheous]

Stalker, just hire this guy. . . to train your BB's :P



"YOU WILL FLY! AND YOU WILL FLY STRAIGHT! AND YOU WILL NOT EAT DIRT UNTIL I TELL YOU TO! DO YOU UNDERSTAND ME MAGGOT?!"




Wilson, the problem with upping the FPS after, is that you are now not field legal. The reason its standardized using .20's to chrony is so that the energy from each gun is measured to be roughly the same. A .43 traveling at 400FPS is going to do some serious damage. With my APS, if I fired a .43 point black at a piece of cedar ((was just a piece on the back my truck at the time)) at roughly 500fps((with.20s)) the .43 embeds itself into the wood, a little over half way. Have to always remember that really the restriction on FPS for airsoft is there to restrict impact energy so that the BB's are still felt, but not damaging to soft targets like skin :P.

Roughly speaking, a .25 is going to hit with the same energy as the .20 in the same gun, just the speed of it getting there changes, but the weight of the round makes up for this. Its not perfectly the same, but damned close enough you won't tell when it hits you.

[ThunderCactus]

What he's saying is our field limits are based on joules of energy, not fps.
And again, although heavier ammo is more accurate, it's going slower and therefore requires an incredible amount of backspin to keep it in the air. But there's only so much backspin you can put on a bb, so using anything above .28g if your shooting under 400fps on .2s becomes less effective.
Bolt action rifles are allowed 470fps, so using .3s is more common.

[CDN_Stalker]

Originally Posted by Wilson

So we can safely say that using a heavier BB, coupled with some modifications that would normally make an AEG skyrocket over the safe 400fps mark, is the best bet?

Accuracy appears to come from the heavier BB, so the .43 listed would be the best, and just use upgraded springs and internals to compensate for the loss of velocity - and then never, ever, ever load it with anything lighter for safety reasons.

There actually is a point of which heavier doesn't do better simply because the range drops off by a large amount. I've shot more 0.43g BBs out of my KSC G19 (got a 120ft kill as well, even though I had to aim just over the guy's head) than I have through my sniper rifles, mainly since there needs to be a lot of hop up to get the BB out to whatever distance. Typically I use 0.30g and 0.36g (for windier conditions), just because they both have their uses and offer a decent range and accuracy (to a point, no airsoft gun can get really far, really accurately) at that range. So while heavier is more *accurate* (stable in flight), going too heavy restricts your ability to get the BB there. One example is 0.36g BBs in my KJW M700. Using 0.30g BBs I can get out past 200ft easily. But with 0.36g, I have to turn the hop up full on, and when shooting level, my BBs drop at around the 150ft mark. Too heavy for the gun. And another gun, I set up a G&P SPR to shoot close to 500fps, we tried 0.36g in it, and they just didn't fly very well or far. Sure, they did thte 100ft range no problem, but it felt like the gun was struggling to get them there well. Hard to explain really, but I recommended the owner just use 0.30g maxium weight.

[Wilson]

Ah, so there are limits to the theory. So where is a good middle ground, a good balance of range and accuracy for an AEG? 0.30g?

[CDN_Stalker]

Really depends on your set up. For an AEG, I'd say 0.28g to 0.30g at the maximum. To run heavier BBs you really need the power to push it far and have a good hop up. And I really don't think AEGs are able to push 0.36g or 0.43g well at all past 150ft when shot level. I haven't done much testing with AEGs shooting heavy ammo, but I'm sure it can be done (letting others speak their experience here now) but still, a good bolt action is the best way to go to get heavy plastic far out there.

[ThunderCactus]

I find .25 and .28 work best, .28 is a little hard to come by in manitoba so pretty well everyone uses .25s in their AEGs.

[CDN_Stalker]

Just gotta hit up BB Bastard to get the 0.28g BBs. Heck, Scarecrow just got in 0.30g from what I've heard, can't wait to try those out!

[pizzainthemorning]

What about hop up friction? I mean, actual contact with the bb takes place during the hop up process. The heavier the bb, the more hop up you have to put on. The more friction:

1. The greater a drop in fps (wouldn't there be?)

2. The greater the chance of shooting off course. We've all seen the hop up pictures in the manuals. When you add too much hop, the bb goes anywhere and everywhere. I don't know, it just seems like brushing the bb with something physically solid (so not like air) would have some kind of effect.

I know heavier bb's are great at maintaining momentum and staying straight in the wind, but wouldn't hop up friction cancel that out a bit?

I use 0.28's in a 400+ fps gun myself, though, I don't know, I'm not always convinced they're "that much" better. Once I get in the parts to fix it I'll have to test.

Alex