FPS and BB Weight

[Komissar]

THIS ARTICLE WAS ORIGINALY WRITTEN ON SEPTEMBER 16^TH 2008

 

To the Readers:              I will again attempt to breach the gap, and clearly explain the differences between firing .20 gram BB’s and .25 gram BB’s. The last article written with some mention of this was on March 4th, 2008 titled " what effects hop-up and BB weight have on your fps".              Here at Diamond Corps our field limit is 400 fps with .25 gram BB’s.  Read on, and I will try to explain why I believe that the heavier ammo is not only safer, but also improves your accuracy.

 First off let me say that I understand that the industry norm is 400 fps with .20 gram BB’s.

             Next for those who are new: FPS is “feet per second”, and is the gauge by which all Airsoft guns are measured for safety and effectiveness. I do not consider myself an authority on Airsoft, the industry, or physics. I am a player, probably much like you, and happen to have an opinion in the matter.

              In the beginning, I used BB’s ranging from .20’s to .25’s. Some cheap, some not. I soon found that the .25 gram BB’s seemed to hold a more consistent path of travel than the lighter BB’s, meaning, that they were more accurate.

             At distance, the wind has less of an effect on the small ball because of the heavier weight. Caught by a slight breeze the .20 gram BB’s would not always hit my target. 25 gram BB’s could still be blown off course, but it took more of a wind to deviate their path.

             Also, the heavier .25’s would go farther before falling to the ground, or losing momentum. Another nice bonus to the heavier .25 BB’s was that they would tend to go through the leaves on the outdoor fields that I play on, where as the .20’s would be deflected.

             So far I have mentioned mostly .20 gram BB’s and .25 gram BB’s however, the same things hold true for .26’s and .28’s. 

             These were the reasons that I eventually went on to .25 gram BB’s. I now find that my shots go even further. The breeze has less effect, and they carry a punch able to cut through small brush which my targets like to hide behind.          

             Now on to the MISSCONCEPTIONS. One wonderful simpleton told me that if I took an AEG firing 400 fps with .25’s and put .20’s in, “it would now fire something like 700 fps”.              Listen, if you don’t understand something it’s ok to say you don’t understand! But it is not ok to mislead others.

             If you fire a heavier bullet (BB) using the same power (fps), it will come out going slower than a lighter one. If your AEG fires .20 gram BB’s at 400 fps, it is my experience that it will fire .25 gram BB’s at 370 fps. The heavier BB weight slows the BB down by around 30fps.

             If I take my AEG which fires a .25 gram BB at 400 fps, and shoot the lighter .20 gram BB. It will fire around 430 fps. There is some degree of variance, but I have found that a change of BB weight from .20’s to .25’s is around 30 fps slower or less.

             If you are someone who uses .20 gram BB’s, take your AEG into your local store, and there they will have a chrono. Buy or borrow some .25 gram BB’s and fire them over the chrono. Subtract the fps number when firing .20 BB’s from the number when you fired the .25 BB’s. It will be around 30 fps +/- depending on the AEG.

Simple? No questions there? On to safety. 

If you have an AEG that fires at 400 fps using .20 gram BB’s, and you fire .12 gram BB’s through it, you will now chrono at approximately 517fps +/- ! OUCH!

Results: Lighter BB’s will cause more damage to people than heavier BB’s AT CLOSER RANGES.

             At closer ranges? YES. A lighter projectile has higher muzzle velocity, meaning faster speed when it leaves the barrel, than a heavier one. The lighter ammo will slow down more quickly due to the effects of air/wind after it leaves the barrel. Lighter weight ammo will do more damage at close range, but will lose speed and fall to the ground sooner.

So, which is more dangerous?

Another reason some people may have a concern is an engagement at close range. I repeat, the lighter weight ammo will do more damage to you at close range than heavier ammo. If you are still worried, then request a minimum engagement distance on your field. “Bang Kill” or “Surrender” rules can also be helpful.

             If you are still having trouble with how this all works, I have a couple more suggestions.

             In NAM magazine issue #14, Howitzer and Reaper did an article on the subject. The article was called “OUCH! BB weight vs. FPS limits” and I recommend reading it. Pages 45 thru 49.

             The last thing I could even suggest if you don’t understand, or simply refuse to believe, would be to get thicker clothes, and a full face mask. At that point, as long as you take your hits, who cares if you feel them. But take your hits.

             Diamond Corps will continue to offer a quality Airsoft experience, with its field limits being 400 fps using .25 gram BB weight. As players, we are not here to injure each other, but to challenge ourselves, and each other, in this highly athletic tactical sport.

             As always, I will openly post the views of others who share interest in the game of Airsoft. Write via the contact button, and share your ideas.

 

My MP5-A5 with a 120 spring fires .25 gram BB’s at 340 fps.

With .20 BB’s it fires at 376. Aren’t you glad I’m using .25’s when I shoot you? May be I should go to .28’s?

 

-        Lighter BB’s are more dangerous than heavier BB’s at close range.

-        Heavier BB’s are more accurate than lighter BB’s at distance.

-        Heavier BB’s have more penetration power than light BB’s.

-        You will not be injured more by heavier BB’s than lighter ones!

 

Let’s all just keep it to 400 fps, and have fun,

- Komissar

[Edric]

Great article! Blast from the past!

[Tank]

this is a great article and i totally agree now some companies are including jules of power with FPS and MPS (meters per second). the thing about jules you know exactly how much energy is being transfered with the bb's this is done by a calculation with the weight of the bb and the fps of the gun. i do agree a heavier bb will mean less injury. great article

[Zach O'Neill]

I do agree that heavier ammo is better, but a friend showed me a link that gave a different view to the .12 gram safety issue.

[Edric]

Speaking of other articles and info, Dr. Airsoft's latest podcast talks about bb's and their energy. Apparently, the UK regilates the force of airsoft projectiles fairly rigerously and has only recently changed their laws to allow airsoft guns to fire at a force exceeding 1 joule of energy for any size and mass of bb.