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FA Forums::News Discussions::How bb weight affects fps, range and accuracy.
Cpl Pwn-90       Posted: 03:47:00 on 02-23-2010
This message edited by Pwn-90. 2010-02-23 06:14:00
Hello fellow airsofters! I recently became quite curious as to the effects different bb weights have on fps, range and accuracy. So, I did some research and decided to post my findings for anyone new to airsoft or anyone curious about the topic like me. In the paragraph below, I have summarized my findings and provided links for reference if you would like to review the raw data for yourself. I take no credit for this information, just in my ability to summarize it. If you feel my summary is inaccurate or misinterpreted, feel free to correct me. Let's begin:

I read that .25 bb's are usually the best for an open environment, as opposed to cqb short range engagements, and I agree based on the florida fps restriction of 400. This is because the greater weight helps stabilize the bb flight path and will effectively increase range and accuracy. .20 or .23's would be best suited for cqb style engagements, because accuracy is not a huge concern, and because the smaller weight utilizes the most fps, getting to the target quicker. Now, we all know that hop-up provides the biggest increase in range. But, if you look at the range graph, you will notice that even with no hop-up, the heavier bb's still traveled farther ( I also watched a bunch of tests a guy did on fps change and accuracy vs bb weight (.20 vs .28) using his CA P90 ( It turns out that using .28g resulted in a fps drop of 50, 5 (if I remember correctly). Therefore, using the recommended .25g for open area engagements, it would only drop fps by about 31 (5/8 = .625 :::: .625/2 [or 50 X .625] = .3125 = 31 fps). A drop in 31 fps would be negligible compared to the increase in range and accuracy. I realize that every gun is different, but these results should be about average for most guns. Whatever weight you choose to use is your own preference, I'm just summarizing what I found. If you look in the bb section of, they have a recommended weight-fps chart that coincides very closely with this data. So, to conclude, increasing bb weight will decrease fps, but the loss will be negligible in comparison to the increase in range and accuracy.

Thanks for reading!

EDIT: apparently the first link isnt working because it's in parentheses? Same as the link posted below. Second one works though.


Cpl Pwn-90       Posted: 03:59:00 on 02-23-2010
I'm not sure if the first link to works or not. If not, just google the whole link and it should come up as the first result.


PFC theonlyBuster (FAU Airsoft)       Posted: 05:51:00 on 02-23-2010
I believe this is the link he was attempting to post:

Here's the full article:


Cpl Pwn-90       Posted: 06:13:00 on 02-23-2010
Yep that's it. Thanks.


PFC theonlyBuster (FAU Airsoft)       Posted: 08:08:00 on 02-23-2010
I've seen quite a bit of these graphs and research topics, and I thank you for posting this because this is great information for all airsoft players to know, new and old.

The problem with BB weights is the fact that .20g BBs are the most common as well as the second most affordable next to .12g BBs. The fact that if I'm desperate for BBs I can walk into a Wal-Mart or paintball store selling airsoft supplies and pick up a pack/bag of .20g or .12g BBs, is kind of the reason most measurements and game rules are based on .20g BBs.

No doubt .25g BBs are usually better to use, but until the day where .25g BBs out-weight [cheap punn] .20g BBs, the .20g BBs will reign at the top in the world of airsoft.

I would LOVE to see a graph just like the one you posted comparing brands in the same weights. I doubt there's much of a difference, but I'm just curious so see the outcome.


LCpl GEEBS_NRG       Posted: 09:13:00 on 02-23-2010
Here's a good read. It's pretty long.. but, you'll feel smarter after reading it.


CPT FA-Ivan       Posted: 14:46:00 on 02-23-2010
Good info. Moved and "stickied"


Cpl Pwn-90       Posted: 15:27:00 on 02-23-2010
@theonlyBuster - I agree with you. The fact that .20g bb's are so widely available and cheap is the main reason they are used. Here is a link to a review comparing the major bb brands using .20g as the weight:

Its got all the graphs and charts you could want. Also check their articles section as they did an update on this review. They tested KSC Perfect, Matrix, and Stealth bb's and compared those results to the ones in the first review.


CPT FA-Caffeine       Posted: 17:44:00 on 02-23-2010
I was wondering if I was going to have to be the one to say "and here comes the science" by posting that Airsoft Mechanics review. Thanks Pwn-90, I'm glad to see more and more people are aware of that site.


Cpl Pwn-90       Posted: 17:58:00 on 02-23-2010
You're welcome. I think more people should be aware of the science and physics in airsoft, and how to use it as an advantage.


PFC theonlyBuster (FAU Airsoft)       Posted: 19:18:00 on 02-23-2010
HUGE thanks for the follow up.
I just finished going over it briefly. I'm quite happy because I "grew up" using Elites and they seem to be in the top of each category.


Cpl Pwn-90       Posted: 19:38:00 on 02-23-2010
Yep the Marushin MaxiBB, KSC, and Airsoft Elite Black / White seem to be the best in the majority of categories.


PV crazycountryman       Posted: 13:40:00 on 03-11-2010
something else to think about, i didnt have time to read all the after posts, so idk if it was mentioned in one of the other websites, i apologize for restating if these were. Simple science (plus getting shot a lot) the .25 over the .20 will have more inertia, and as im sure all of you know, something with more inertia is harder to stop (thus the more range, and better accuracy). If you take two shots with the same gun, at the same distance, one with .20 one with .25, the .25s will hurt a little more, because of this inertia.

Another fact of the matter, something with a hevier mass (.25) will be slower to start moving. Which sounds like it just hurts fps, right? Well it helps something else, the bb starting out slower, means that air is traped in front of the piston head longer, which means the piston head doesnt hit as hard. Everybody im sure has heard on several occasions that dry shooting your gun is bad, and this is the reason. the less whieght bb (or no bb) causes the piston to move forward faster, and the piston head hits harder. So especially if you do not have an aluminum piston head, it can severely damage the piston head. For anyone who has had a piston head break mid-game, you know what im talking about, lol. I mysyelf much prefer using .25s....


PV MiA Ike       Posted: 17:00:00 on 03-31-2010
In the same way that .25s have an advantage over .2s, .3s have that same advantage over .25s. I use .3s in any gun shooting over 350fps. They are the optimal weight for outdoors.

Check out this link. Its got a ton of graphs and mathematical reasoning comparing BB weights and the range you will get at different velocities.


AB Lero       Posted: 18:33:00 on 05-26-2010
Love the info, research, and math wiz shown there, but i can assure you that fps does not directly affect "maximum effective range" (There being a difference between maximum range, and maximum range you can hit the target intended). My CA M14 shoots 280-300 fps and has accurate range right along side most bolt action rifles.
To summ it up, FPS translates into how fast your bb will reach the target.


Cpl Pwn-90       Posted: 18:41:00 on 05-26-2010
Umm yeah.. that's basically what was summed up in the original post.


CPT FA-Caffeine       Posted: 20:14:00 on 05-26-2010
There have been some studies regarding FPS, BB mass, and max. effective range but I can't for the life of me seem to find them now. So you'll just have to take my word for it :)

Essentially the conclusions were that initial FPS had little to no effect on FSP at standard airsoft target distance (say 100 feet). Improvement in accuracy and max effective range were likewise negligible. I really wish I could find it again as I was quite surprised with the results.


PV airsoftmaster=me       Posted: 22:16:00 on 09-29-2010
k so i have this 520 fps sniper and some of my friends hate to get hit with it. im using .2 and i can hit people and 150-200 feet but maybe thts just me. but i want the fps down a little so my friends will still have wars with me. if i go up to a .23 or .25 what will be the difference in fps. i know it will increase accuracy but how much will it bring it down by????


CPT FA-Ivan       Posted: 22:36:00 on 09-29-2010

check this one:


Cpl Pwn-90       Posted: 14:58:00 on 09-30-2010
.23 about 500-495ish, .25 about 485ish. Its still gonna hurt just as much, the reduced energy has been converted into increased mass


PV airsoftmaster=me       Posted: 18:08:00 on 09-30-2010
ok ya i figured tht it will hurt. so do u have a formula to figure this out or are u just guessing. and then what happens when i go to a true sniper bb. a .32 what will that be at


Cpl Pwn-90       Posted: 19:56:00 on 09-30-2010
Well without going through the whole formula, about 450 fps with .32s. Again, its still gonna hurt just as much


SR zombiehunter       Posted: 21:19:00 on 06-22-2012
This message edited by zombiehunter. 2012-06-22 21:21:00
0.2g is way better than any other bb weight cuz its the least expensive and doesn't ruin your aeg. Anything heavier is personal preferenc. Also, whether it hurts or hurts more they all hurt the same. Now if we're talking real firearms, that's a different story. I use black 0.2g on 340fps for cqb.


CPT FA-Fireman       Posted: 15:28:00 on 06-23-2012
Can you explain how heavier bb's ruin your gun? I use .25's in everything I own. I choose the weight because most fields in Florida have such heavy foliage and .20's don't have the punch that .25's do.

CQB, .20's are perfectly fine. I can see the benefit of their higher FPS being a benefit too with the pace of CQB and trying to hit a target before they duck back behind cover. For the sake of keeping everything standard, I still use .25's in cqb because I'd rather just use the same thing in all my guns all the time and not have to deal as much with adjusting hop up or having to "re-learn" how my gun is going to perform from bb to bb.


Cpl Pwn-90       Posted: 22:59:00 on 06-23-2012
I would also like to know how heavier bb weight hurts a gun


SR zombiehunter       Posted: 23:18:00 on 06-23-2012
heavier bbs ruin aegs? Thats new! 0.2g are way faster than heavier bbs.


Cpl Pwn-90       Posted: 00:27:00 on 06-24-2012
We've already established that 0.20g bbs are faster than heavier ones. I'm still waiting for an explanation on how heavier bbs ruin an aeg


GySgt Cupcake (War Pigs)       Posted: 13:03:00 on 06-24-2012
Personally, I trade the slight increase in accuracy and the increase in punch of a .25 over the slight increase in speed of a .20 and for a whole $2.00 per 5000 I don't think that prohibitive cost is much of a factor.

I'm not sure what you meant by the won't ruin your gun part of that statement. Any other pretty much emcompasses .12g and then .23g through .45g.


CPT FA-Fireman       Posted: 13:34:00 on 06-24-2012
zombiehunter - You wrote:

"0.2g is way better than any other bb weight cuz its the least expensive and doesn't ruin your aeg"

That's what we are asking you to explain. :-)


SR zombiehunter       Posted: 18:53:00 on 06-30-2012
it all depends on your fps. saying .25 is beter than .2g is false. but to say .2g is better than .25g is true. thers really no explanation needed. sidearms, smg and assault dont really need accuracy in airsoft unless your using a sniper then you need accuracy.


Capt. FA-Sean       Posted: 20:49:00 on 06-30-2012
Is there no explanation needed, or you can't explain the explanation that is needed?


CPT FA-Fireman       Posted: 13:32:00 on 07-01-2012
Your statements don't cover a large number of variables and you still have said NOTHING about how heavier bb's are going to "ruin your aeg". Please explain how a heavier bb ruins your AEG or I will simply remove your posts so other players don't get mislead by what seems to be false information.


CPT FA-Fireman       Posted: 13:32:00 on 07-01-2012
With regards to a standard AEG, If you're playing outside and there is a lot of foliage you are going to want something heavier than .20's. If you are outside and there is a lot of wind, you are going to want something heavier than .20's.

If you are indoors, no wind, nothing you are trying to shoot through like bushes, .20's are fine. They will be just as accurate as .25's because there will be no external forces they have to compete with.

If you are using a gun with a higher FPS and you try to use bb's that are too light, when they leave your gun they will encounter so much air resistance that they will lose their momentum far faster than a heavier bb will over the course of 50-100 feet. It's why people complain about a gun being hot when someone is using a heavy bb. Even if they are hit at 150 feet, a .20 shot at 500 FPS is going to be carrying FAR less inertia and when it hits the person will be traveling at speeds much less than 500.

If you shot a .30,.40, .43 out of a gun which shot .20's at 500, the higher weight bb is going to leave the gun at a slower speed but it is going to maintain this speed for FAR longer than the .20 would because the increased mass is going to hold up against air resistance much better then a .20 would. When the bb hits its target it will still be carrying a similar amount of force as it left the gun with.

With a side arm, sure you can use a light bb inside. If I'm outside I'm still going to use .25's because I want to know that my side arm has a higher chance of punching through some leaf that may be between me and my target. If I'm in a situation where I have to go to a side arm, I better know that it's going to do the job.


Cpl Pwn-90       Posted: 14:34:00 on 07-01-2012
Look man, as Fireman said, the only time 0.20g is better is in an indoor cqb environment where precision comes second to speed. Otherwise, its pretty much a disadvantage to use in any other environment. Still waiting for that explanation of how heavier bbs ruin a gun.



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