Good way to know if under 400fps with .25s?

[Rabbit]

I currently do not have a chrono at the moment and just carry .25g bbs on me.

I've done the poor mans chrono with the pop can but it wont give you an accurate estimation with .25s.

Is there any other good way to know if you're under 400fps with .25gs?

** Currently using the .25s it goes straight through from one side of the pepsi can to the other, it doesn't break through the bottom of the can in the middle but it does dent it fairly well and even leaves a crack sometimes.

[m102404]

There's no way to know how fast something is going without a chronograph. (even if you rig up speakers and measure impact sounds...you're still doing a chrony)

Either buy one...or use a buddy's...or use a field's chrony.

You'll roughly have to add 40fps to relate what the velocity would be with 0.20's vs. 0.25's. And this only works with AEG guns...you can't relate velocity measurements of different weights with gas guns.

[kullwarrior]

Do you have the following?

Computer w/ a mic?
Microphone for computer? (not integrated ones)
Measuring tape? (Atleast 2m distance)
2m distance?
Target box (with hard backing)

If so what you could do is setup a distance (make it atleast 2m), one end will be the targetbox while the other end is the muzzle. Make sure where the bb hit is exactly 2m (or whatever distance you use)

Now place your microphone exactly 1m between the target and the muzzle (but not in line of fire)

Use computer recording program like Audacity set up a recording and shoot it. The first spike in sound indicates the bb leaving barrel while the second spike is the bb hitting the target.
Highlight the time between two spike, find the time difference (generate silence feature will give you a second)

Now that you have the distance and time, you can derived velocity. (Velocity = distance/ time) If you can derived velocity at 0.25g you can find the 0.2g velocity via (Energy = 1/2*mass*velocity^2)

If you're meausurement are off, the result will be off, but I found this more accurately than Madbull chrono.

[cooney]

You can chrono at my place Remy or PM THe_Silencer for his chronograph.

[Cobrajr122]

Originally Posted by Cooney

You can chrono at my place Remy or PM THe_Silencer for his chronograph.

Do this, and use 0.2s
All fields use 0.2 when measuring FPS, unless they are smart and keep a conversion chart on hand.