FPS
 

My V4 S-system was shooting 400 fps out of the box with .20g. Obviously I would not be allowed to bring this to an indoor game. How much would velocity change going to a heavier bb? Or, do you not want to use heavier bb's indoors.

You'd want to change your spring and such. As, FPS tests at games are done with .20 bbs, even if your going to be using a heavier.

fps can be misleading. if you know some basic phsyics you should know about inertia. Even though the .25g is traveling slower it will still hit with the same if not more energy *AKA joules*. In all honesty this is what we should be using and not FPS for field limits. That way you can be "cronoed" in on any weight of BB.


Long answer short, you need a spring or a velocity reducer but I have heard those are crap.

What's important is the muzzle energy, not velocity. When we refer to 400 or 350 fps as 'field legal', that's assuming the use of .2g BBs. While using a heavier BB will reduce the velocity, the heavier weight of the BB will translate to the same energy. So a gun shooting 400 fps with .2 produces 1.49 Joules of energy. The same gun shooting a .28g BB will be shooting at 338 fps, and STILL producing 1.49 Joules. of energy.

The only way to reduce your velocity is to swap your spring.

Although a heavier BB will reduce the velocity of the projectile it will not reduce it's energy.

The idea of a 350 FPS limit is to reduce the possibility of injury from close range hits.

the injury potential of a 400fps .2 is the same as the potential of a 340 fps .25

There is no need to use havier BBs indoors you don't have the wind or vegetation penetration issues to contend with .. and the range is typically all well within the effective range of the weapons anyway.

drop your gun down to 340 with a weaker spring with .2 bb's. indoors or outdoors with some heavier bbs you won't need more fps then that unless its extremly windy

there yah go the same answer 3 different ways, pick one.


Edit* 4 different ways...

Good for you on paying attention to this. When some of the original batch of hot clones came out, guys were playing indoors with them. A buddy of mine left a game with 3 BBs embedded in his back....nasty stuff.

Stick a M90 rated spring (90 meters/sec = ~300fps) in it. For a lot of CQB there's really no need for much more and it'll just plain hurt your friends. A lot of times you end up in a tight spot with shots really close up and it's nice to know in the back of your mind that you're not going to be dishing out batches of bloody welts.

Modify make great springs...their S90 spring would be a good one. Depending on your setup, it'd give anywhere between 300-340fps w/0.20's. It's a wide range of FPS...and that's another good reason to aim lower than the maximum listed limit.

Best of luck.

Tys

M90 or M100 will bring you down to what you need. IMO 350 is unnessecary since CQB distances are so short that a velocity change will only affect the time it takes the BB to exit the barrel and hit someone by milliseconds if not less than that.

330 is probably a safer bet (since a lot of fields use that as the limit) and as such the M90 is probably a better spring to go with. Remember FPS limits are just that a limit not a goal.

somehow 0.3's travel around the same speed and they hit ALOT harder due to the weight. i think your best bet is just to change the spring. it's cost effective and will ensure that you have the peace of mind aaha

did you even bother to read the other responses. Some how you managed to repeat what we just said and actually still not give any useful advice...........

seriously this thread can't go any further.

Then why are you continusly adding usless posts, nobody cares about post counts here you know.

more posts I Have the more 1337 I am. Its simple math. Oh look another one!

I love the Modify springs, but the 90 seems really susceptable to losing power. Must be something in the steel or the tempering, but I put one in my MP5A5 last year, was getting a good 330fps out of it, earlier this year saw it was sitting around 300fps, and last game I played it was 280fps. This is after firing a few shots on semi to clear the chamber and set the piston full forward.

Prometheus MS90SP is nice.
A spring swap is one of the easiest things you can do to your gun. When you do it yourself, just use mechbox.com and youtube guides on a S-system (JG or TM, ect.) disassembly guides, and make sure to not touch anything else, or unevenly torque your mechbox shell.
Should put you around 300-320fps? I think?