[demoncase]

http://i10.photobucket.com/albums/a146/demoncase/FPS.jpg

You asked for it so I built it: A handy dandy graph-cum-cribsheet for working out your Power from your FPS.
Common BB weights along the top of the table (this is why the graph looks 'bumpy')
Common power levels to get the 'expected FPS' down the left side.

Of note, in the 0.2g band we all tend to use as a 'standard':~
1J = ~328fps
1.15J = ~350fps
2.3J = ~500fps
These demonstrate that the rest of the data is correct...Feel free to check my figures.
I've rounded to the nearest integer- hence 328.4 would be shown as 328. 328.5 would be shown as 329.

SO, using the table/graph
~If you know your BB weight and FPS, this will tell you your power level.
~If you know your FPS with a certain BB weight this will tell you what FPS you will get with other BB weights
~If your FPS has changed (due to temperature or wear) you can work out how much power you've lost or gained.

NOTES:
1. This data is based on the standard equation for Kinetic Energy= (0.5x (Mass x Velocity squared)).
It's a fundamental physical law that's been in use for over 200 years. It can't be argued with, so don't bother- you'll only end up with physics all down your front. ;)

2. This graph works for both 6mm AND 8mm BBs REGARDLESS.
It does not matter what SIZE the projectile is- Only weight and FPS...If its the size of a housebrick and weighs 0.2g then you can plot the power/resultant FPS using the above data. Volume is not in the Kinetic Energy equation, only mass and speed.
You can argue until your blue in the face about "8mm hurting less because it's a bigger diameter, innit" and other such non-measurable/ entirely subjective factors- this is the pure mathematics of it with which there is no argument.

3. This table DOES NOT take into account 'internal' variability.
~The inherent variablity of your RIF (Shot-to-shot consistency, wear from game to game)
~The variability of the chrono, (Accuracy may be as low +/- 5%!)
~Variation in weight (not every BB will be exactly 0.2000g)
~Optimisation (your barrel &HOP might seal brilliantly with 0.25g but have too much drag/flow-by with 0.2g)
~Environmental factors (Hotter might increase spring rates and improve gas flow)
The tolerances for a site should take these into account- other sites operate an absolute fps limit. Always leave yourself plenty of room between your site limit and your gun's power.

4. Link this with my other thread on 'The Mathematics Of Making a Kill' to realise why all the extra FPS in the world make little ultimate difference to your likelyhood of a hitting your target :)

FINAL POLITE REQUEST
This thread isn't a "springboard" to have a gripe about the Whys/Wherefores/How-We-Got-Theres of the 1J "thing", Skirmish site FPS limits/ insurance and other legal type issues
We are where we are, and let's leave it at that!-
All Such posts that miss this polite request will get quietly pruned

[Boomer]

Excellent demoncase great piece of work.

I'd echo the Final request there is already a thread to discuss FPS and Lethality.

[ShadyDave]

Excellent work Mr Case :)

[trafman]

You might live in the 5th worst city but I aint going to argue with you on yet another staggering piece of work, many thanks for all your efforts.

cheers


trafman