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BB Weights


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#1 WiN&LeGeNd

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Posted 17 December 2008 - 08:19 AM

I'm looking for user experience here, I do have some data that is calculated, now using basic physics such as velocity, inerta and friction coefficents for air at approximately 400 fps a .3g bb will actually travel farther and have a higher AVERAGE velocity than a lighter weight bb due to increased inertia. I know i've run .28's vs .25's and in my 405fps SLR with Prom barrel I was actually able to confirm that, my absolute max range was about 5 feet or so farther with .28g's as opposed to .25g's. Since the KWA will be shooting around 420 ish and I want max range and accuracy I think .3g bb's would be appropriate. Any brand suggestions? Airsoft mechanics put KSC's in the top 5, but user experience is always helpful. Thanks.

#2 karMeister

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Posted 17 December 2008 - 06:34 PM

View PostWiN&LeGeNd, on Dec 17 2008, 08:19 AM, said:

I'm looking for user experience here, I do have some data that is calculated, now using basic physics such as velocity, inerta and friction coefficents for air at approximately 400 fps a .3g bb will actually travel farther and have a higher AVERAGE velocity than a lighter weight bb due to increased inertia. I know i've run .28's vs .25's and in my 405fps SLR with Prom barrel I was actually able to confirm that, my absolute max range was about 5 feet or so farther with .28g's as opposed to .25g's. Since the KWA will be shooting around 420 ish and I want max range and accuracy I think .3g bb's would be appropriate. Any brand suggestions? Airsoft mechanics put KSC's in the top 5, but user experience is always helpful. Thanks.


just to clarify. 400 fps on a .3 will mean you are sooting around 480 on .2s. Or do you mean 400 fps on .2s?
I do see a diff of 5-10 ft when i switch to .3s but if affects the fps alot...it does hit hard  :lol:

#3 brooklyn468

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Posted 17 December 2008 - 06:40 PM

Yeah I recently switched to .25s over .2s. I realized the .25s just keep going and going...

#4 karMeister

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Posted 17 December 2008 - 06:43 PM

View Postbrooklyn468, on Dec 17 2008, 06:40 PM, said:

Yeah I recently switched to .25s over .2s. I realized the .25s just keep going and going...


you should also notice that its alot more consistent  :lol:

#5 mop

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Posted 18 December 2008 - 02:26 AM

I tried .20 and .25 BBs too. Clearly better results with .25 BBs.
You can try to put in a new bucking and a H nub for better accuracy.

#6 WiN&LeGeNd

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Posted 18 December 2008 - 05:43 AM

It all comes down to physics, now my reference to 400 fps is 400 fps in reference to .2's, so that same power gun on .3's would be around 320~325 ish, BUT, although the initial muzzle velocity is lower with a heaver ammunition, it is actually faster overall because of increased inertia, momentum is conserved much more efficiently. So while a .3 gram bb may exit your gun as lower velocity it will maintain it much better, resulting in a lower travel time at long ranges. So at 200 feet a .3 gram according to calculation would actually reach its destination before a .2 gram bb would. Now if your close range or CQB you'd be better off with lighter ammo because of the high muzzle velocity, in that case .2's would superior. It just depends on what your using it for. If range and accuracy is the goal then go heavier, if quick response and short range is called for then go lighter ammo.

The site is no longer up, but I at one point had read through it, a fella who had a BS in either Mechanical or Civil Engineering took the time to calculate distance and average velocity from .2g up to .43g bb's for each increment in spring energy starting from 250 fps to 600fps something(with the base point being measured with .2g bb's) . He then verified the results by actually testing one complete set of data and all the results were within 5% margin of error. The link was http://cybersloth.or...ctory/index.htm but it is no longer valid, so the information has been lost unless it was moved somewhere else or is available in another form. I'm no good at physics other than basic conceptual understanding, which is why I'm an electrical engineer ;-) but I did read though it and found it to be extremely usefull and tested it myself and found the results to be true. Now obviously there is a bb that would be too heavy or slow, but in the 400~450fps range(with .2g's base measure) a .25 to .3 will give the best range and fastest average velocity over the entire flight path of the bb. Going heavier becomes un-optimal just as going lighter than those ranges of weights do. I think there was only about 3 or 4 feet difference between .25 and .3, but the .3 would give the best stability. Now that I think about it I kinda answered my own question, imagine that, lol.

#7 karMeister

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Posted 18 December 2008 - 10:05 AM

View PostWiN&LeGeNd, on Dec 18 2008, 05:43 AM, said:

It all comes down to physics, now my reference to 400 fps is 400 fps in reference to .2's, so that same power gun on .3's would be around 320~325 ish, BUT, although the initial muzzle velocity is lower with a heaver ammunition, it is actually faster overall because of increased inertia, momentum is conserved much more efficiently. So while a .3 gram bb may exit your gun as lower velocity it will maintain it much better, resulting in a lower travel time at long ranges. So at 200 feet a .3 gram according to calculation would actually reach its destination before a .2 gram bb would. Now if your close range or CQB you'd be better off with lighter ammo because of the high muzzle velocity, in that case .2's would superior. It just depends on what your using it for. If range and accuracy is the goal then go heavier, if quick response and short range is called for then go lighter ammo.

The site is no longer up, but I at one point had read through it, a fella who had a BS in either Mechanical or Civil Engineering took the time to calculate distance and average velocity from .2g up to .43g bb's for each increment in spring energy starting from 250 fps to 600fps something(with the base point being measured with .2g bb's) . He then verified the results by actually testing one complete set of data and all the results were within 5% margin of error. The link was http://cybersloth.or...ctory/index.htm but it is no longer valid, so the information has been lost unless it was moved somewhere else or is available in another form. I'm no good at physics other than basic conceptual understanding, which is why I'm an electrical engineer ;-) but I did read though it and found it to be extremely usefull and tested it myself and found the results to be true. Now obviously there is a bb that would be too heavy or slow, but in the 400~450fps range(with .2g's base measure) a .25 to .3 will give the best range and fastest average velocity over the entire flight path of the bb. Going heavier becomes un-optimal just as going lighter than those ranges of weights do. I think there was only about 3 or 4 feet difference between .25 and .3, but the .3 would give the best stability. Now that I think about it I kinda answered my own question, imagine that, lol.

You also have to consider the backspin that the hop gives to heavier BBs. The Heavier BBs can also maintain the spin alot more thn lighter ones

#8 WiN&LeGeNd

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Posted 18 December 2008 - 10:48 AM

View PostkarMeister, on Dec 18 2008, 01:05 PM, said:

You also have to consider the backspin that the hop gives to heavier BBs. The Heavier BBs can also maintain the spin alot more thn lighter ones

That is an excellent point and probably one of the bigger contributing factors to their superior performance in comparison to a lighter weight bb.

#9 Lt. Tony

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Posted 20 December 2008 - 09:04 PM

I have a theory in regards to BB weights. Use what ever weight BB that will get you gun firing 380-400. If there are two weight in this category use the heavier. By following this theory your gun should have nice accuracy, while maintaining power, and speed




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