BB weight for field play.

[Kennytaker]

Newb question. After they chronograph your AEG with 0.20bbs can you just switch to the BB weight you want? Or can they just chorno with the weight bbs you use? Or does all that just depend on the field you play at?

[ThunderCactus]

Depends on the field and what kind of gun you're using.
GBBR's must chrono with the BB weight they are going to use
AEG's can chrono with either .20s or the BB weight they're going to use

Chronoing with something other than .20s with an AEG, or anything with a GBBR, just requires math to figure out how many joules you're shooting at.

[Grudge]

.25g and .28g are common weights. But it will really depend on your gun, type of hopup and FPS. Some guns shoot way better with a specific weight.

[Kennytaker]

Ok so, if I want to use .30s then what kind of fps should I look for? wanna be legal for field play (no CQB) thanks.

Weapon is a standard AEG M4 and a M9 pistol thanks again

[MaciekA]

Originally Posted by Kennytaker

Ok so, if I want to use .30s then what kind of fps should I look for? wanna be legal for field play (no CQB) thanks.

Weapon is a standard AEG M4 and a M9 pistol thanks again

Just off the top of my head, I've got an M4 shooting with .20g BBs at 352 and about 310 with .25g BBs when I chrono'd on Saturday. My chrono reads the same number of Joules in either case. I get to play everywhere I go, with decently high RoF (~20rps) and my internals are not under crazy strain.

The last game I was at had a chrono area set up with each signed up attendee's name listed on it. If you didn't chrono, you weren't going to be playing. You walk up to the chrono station and one of the organizers hands you a mag loaded with their trusted 0.20g BBs. You fire through the chrono and they record your averages next to your name. If you fire hot, you either get a restricted role (eg: semi-only, minimum distance for engagement) or if it's way too hot, you get a loaner gun. You should expect to have to do this sometimes, but your mileage may vary depending on where you play...

If you want to play often at various fields, both indoor and outdoor, and want to be able to fire full auto and semi with zero hassle, buy yourself a bag of 0.2g BBs and make sure your AEG is firing under 400fps, preferably around 350-360 if there are fields with CQB restrictions.

Hope that helps

[L473ncy]

At 400 FPS using .20's you'll want to be at 327 or less on .30's.

Use this calculator and play with the variables.

http://www.arniesairsoft.co.uk/?filn...s/fps_calc.htm

The key thing to remember is you want to use the ENERGY of the projectile not the speed of the projectile (I think Illusion or ThunderCactus had a pretty good writeup about this in a post somewhere).

Also note that with GBB systems that the relationship between speed and weight isn't linear. It's almost exponential so you need to use the BB's you're planning on using when you chrono but also do the right calculations for energy.

A GBB pistol shouldn't be over the limits (unless you have a 330 FPS limit for pistols for safety when mercying or at less than 20ft. engagements) but this is a concern for GBBR's which can go way over field limits.

[Styrak]

Originally Posted by L473ncy

At 400 FPS using .20's you'll want to be at 327 or less on .30's.

Use this calculator and play with the variables.

http://www.arniesairsoft.co.uk/?filn...s/fps_calc.htm

The key thing to remember is you want to use the ENERGY of the projectile not the speed of the projectile (I think Illusion or ThunderCactus had a pretty good writeup about this in a post somewhere).

Also note that with GBB systems that the relationship between speed and weight isn't linear. It's almost exponential so you need to use the BB's you're planning on using when you chrono but also do the right calculations for energy.

A GBB pistol shouldn't be over the limits (unless you have a 330 FPS limit for pistols for safety when mercying or at less than 20ft. engagements) but this is a concern for GBBR's which can go way over field limits.

Not linking to the BB Bastard calculator?! Blasphemous!

http://msed.bbbastard.com/index.php?...d=53&Itemid=57

[Kennytaker]

Sweet thanks for the input everyone.

MaciekA: do you play any fields in the GTA area or close by you would recommend? Prefer outdoors.

[Ricochet]

0.20's are only really good for chrono'ing. 0.25 is a standard all around, good for indoors or CQB. 0.28's chop through brush well, and good for long range shots. But now you will see a visible decrease in velocity. 0.30's are a lighter sniper round. I find they travel too slow in an AEG, and are unpredictable in short barreled guns. 0.25's work very well in pistols as well, as 0.23's seem just a little too light to stay on target. Every gun has its own balance though. Between bore size, spring power, barrel length, air seal ..ect. Find the BB that works best for your gun. I recommend BB bastards. They are a very true BB, and will make it easy to see what weight you want.

99% of the time, the field fps limits are strictly based off of 0.20's. So that's what you chrono with, then you can switch to what you want after. As a heavier BB will decrease velocity. And lighter than 0.20's will be completely too unpredictable. It is important to pay close attention to the rules of the field your playing on though.

[a_sock]

I understand that a greater velocity often yields poor accuracy, but have a question about controlling muzzle velocity with weight. Here's an example of what I mean. Gun A shoots 350 fps On .2 and is slightly more accurate than gun B, which shoots 450 on .2 . If gun B used .3 bbs to shoot the same fps, would there still be that difference in accuracy?

[slink182]

Originally Posted by a_sock

I understand that a greater velocity often yields poor accuracy, but have a question about controlling muzzle velocity with weight. Here's an example of what I mean. Gun A shoots 350 fps On .2 and is slightly more accurate than gun B, which shoots 450 on .2 . If gun B used .3 bbs to shoot the same fps, would there still be that difference in accuracy?

The inaccuracy seen from using a light weight in a hot gun is typically from the turbulence created around the BB at the higher velocities. A heavier weight in the same hot gun, however, would provide needed stability during BB flight due to its momentum during travel. Also, a heavier weight will be less inclined to be affected by crosswinds, which obviously will affect accuracy. So, to answer your question - yes, a 0.30 g BB would shoot with greater accuracy at the same base FPS. (To further clarify, I'm assuming that you are not performing a spring swap, so your 450 with 0.20 would likely translate to about 380-390 FPS with 0.3 g weights.)

However, weight isn't everything (just like velocity isn't everything). Other considerations includes the tightness of the inner barrel (less slop = greater accuracy), the quality of your airseal (less seal bleeding = greater velocity), and the type of hopup & bucking (to create the necessary backspin on the BB to counteract gravity and provide flight stability).

[Ricochet]

Every time you increase weight your fps lowers, but your BB tends to fly a little straighter. This isn't always the case. Accuracy can be affected by a number of things. General rule of thumb is a heavier round will fly straighter. But a gun with lower fps will eventually hit a wall. By that I mean that a higher weight BB will be too heavy to be effective. A higher fps gun will eventually run into an issue where a certain BB weight will be unstable, and won't fly straight. Almost any gun can handle a 0.25, or a 0.28 though. You can mitigate these issues by adding a longer barrel for flight stabilty, or a tighter bore to straighten out a lighter BB. Increasing or decreasing fps can also affect these things. Trying to find the right balance of power, range, and accuracy. A standard AEG combination seems to be a 6.01 tightbore with an m130 spring running a 0.28 round. But no two guns will react exactly the same. Also having a good spin put on the BB by a proper hopup assembly can help make a world of difference.

If you really want a better rundown of BB weight afflictions, talk to an "experienced" sniper. They are generally the best at finding that perfect balance. For a assault weapon the best way is to get your gun into the 400ish fps range with 0.20's. With a combination of spring power, good airseal, and barrel length versus bore. Then try a few BB weights to see what works for you. That way you won't have to overly change your gun after the fact.

Also remember that certain guns come with specific high end upgrade parts that are made to work well together. Companies like PDI, Laylax, Systema, RA Tech, and Guarder seem to put out dependable parts.

[Kokanee]

Originally Posted by ThunderCactus

...
GBBR's must chrono with the BB weight they are going to use
AEG's can chrono with either .20s or the BB weight they're going to use...

I am curious why you would distinguish between GBBRs and AEGs, as I have never played on a field with this policy?

[L473ncy]

Originally Posted by Kokanee

I am curious why you would distinguish between GBBRs and AEGs, as I have never played on a field with this policy?

The heavier the BB going through a gas gun the more energy it picks up while in the barrel due to more energy transfer from the gas used to propel it. A spring is relatively linear in energy when you use heavier rounds but it's my understanding that with gas guns the energy "curve" by using heavier BB's is more akin to the equation "n log n".

So you might be firing at 1.4J with .20's on an AEG and still do 1.4J on .28's it will just go slower but with a GBBR or GBB system if you're at 1.4J on .20's then switch it up to .28's you might see 1.6J even though it will travel slower it has more energy. Note remember that we keep stressing FPS limits but rather we should be stressing energy limits.

[Ricochet]

It all has to do with joules. A heavier round will always have more force or energy than a lighter one. An AEG is spring powered, so the thought is that as you increase BB weight you bring down the fps, but the energy won't change drastically due to this fact. In a GBBR you are using compressed gas to project the BB down the bore. So the gas will expand at a certain rate no matter how much heavier the BB is. So instead of seeing a huge fps change from using a heavier round your more likely to see a jump in joules if force. And joules is what can really hurt someone. Each fields have or may have it's own fps/joules limits. And they can calculate the energy output of a projectile by knowing it's velocity and projectile weight. I hope this helps. There are many posts within ASC that can give more detailed information on what to look for.