FPS

[D2D]

Hi there. I bought a rifle a very long time ago and am just now looking into going out and playing; I have a question about FPS limits.

In an outdoor field with full gear, would you notice one or two hits from ~400 FPS (.2g BB) and call yourself out?

I ask because I have a gas gun with a few 30-round magazines, and I'm assuming (incorrectly?) that AEG players in general play on full-auto. I, on the other hand, need to be very conservative with my shots.

[chaz]

very incorrect. Most people I play with run semi and run mid caps.
You will notice the hit depending on where it is and how close you are.
If you are shooting 400fps why not put in a better bucking and some heavier BB's? That will get you better shots with a little more umph on the receiving end.
My 2 cents anyway.. No change please

[D2D]

Ah, you misunderstood. I wouldn't be shooting .2g BBs - I was just using that as a reference point. I would be using .25g or heavier.

Sent from my Nexus 5 using Tapatalk

[Rossco66]

Unless you are running or are 150 feet away, you will feel it if you are wearing any type of normal clothing. If you are sporting a ghillie suit you may not feel it. A direct hit from 100 feet on an arm with just a level of BDU cloth in between your skin and the BB will leave a welt.

[Cobrajr122]

Originally Posted by chaz

If you are shooting 400fps why not put in a better bucking and some heavier BB's? That will get you better shots with a little more umph on the receiving end.

If he is already shooting 400FPS with 0.2g (1.5J) on a gas gun, using heavier BBs will place him FAR over the 1.5J limit.

[Rossco66]

How do you figure? He's at 1.48J now and a heavier BB will have a slower FPS

Originally Posted by Cobrajr122

If he is already shooting 400FPS with 0.2g (1.5J) on a gas gun, using heavier BBs will place him FAR over the 1.5J limit.

[chaz]

FPS is velocity where Joules are kinetic energy.
Increase the weight of the BB and the Kinetic Energy increases.

[MultipleParadox]

Originally Posted by Rossco66

How do you figure? He's at 1.48J now and a heavier BB will have a slower FPS

I guess he's referring to what's commonly known as "power creep", where a heavier BB will result in slower initial speed, and longer delay before the BB exits the barrel

This result in a bugger gas build up behind the BB and translates to an increase in energy.

Technically, if at 1.48J with .2, a gas gun will effectively have an higher energy output with heavier BBs; I wouldn't think that increase would be *that* high though; I'm sure there are charts around the web that people put up after actual tests

Edit:
Chaz, not exactly
Velocity and energy are tightly related; increasing weight doesn't increase kinetic energy, as the velocity also decrease

[chaz]

Found one!

[MultipleParadox]

More discussion on this here

http://www.airsoftsociety.com/forums...73/index2.html


Actually, tons everywhere if you google :P

[Cobrajr122]

Originally Posted by Rossco66

How do you figure? He's at 1.48J now and a heavier BB will have a slower FPS

This is how I figure.
Gas behind a heavier BB has more time to expand and exert its force onto the BB, this in turn give it more energy than it would receive had this been done in an AEG.

Originally Posted by Cobrajr122

I just tuned the 509mm barrel for 1.3J on BBB 0.2g then put BBB 0.28 in and got an increase of 0.15J, up to 1.55J.

Apparently this knowledge as not as wide spread as I thought it was on ASC, guess we need to do some more work on disseminating this very important information.

Originally Posted by MultipleParadox

More discussion on this here

http://www.airsoftsociety.com/forums...73/index2.html


Actually, tons everywhere if you google :P

Tons of information on here too. There is a reason there are a few of us pushing game hosts to set ENERGY limits and chrony for energy and not FPS, ESPECIALLY with gas guns.
This method is being followed for Nightfall this year.

Originally Posted by MultipleParadox

Technically, if at 1.48J with .2, a gas gun will effectively have an higher energy output with heavier BBs; I wouldn't think that increase would be *that* high though; I'm sure there are charts around the web that people put up after actual tests

Yes, it is that high. There is a significant increase as seen above.

[chaz]

Originally Posted by MultipleParadox

Edit:
Chaz, not exactly
Velocity and energy are tightly related; increasing weight doesn't increase kinetic energy, as the velocity also decrease

Wrong. Its physics. The weight of the heavier BB will have a harder impact when it reaches its target. It does take longer to reach the target however.
Check out the picture I posted, it puts Joules against FPS

[Rossco66]

Good to know. A lot of moving parts. I would have thought the energy output would have been stable and the heavier BB therefore resulted in less velocity.

[chaz]

Less velocity but higher impact.

[Cobrajr122]

Not only is the energy higher at the muzzle, heavier BBs hold onto that energy for longer, and transfers more of that energy to a surface it collides with.

So a 0.2g shot @ 1.5J will contain less energy at 100 feet then a 0.25 that was shot @ 1.5J will.


http://msed.bbbastard.com/ATP/01-c-01.htm