ICS M4A1 FPS.
 

I've got an ICS fixed stock M4, just got it chronoed and was slightly dismayed to see that it's shooting 330-340 FPS, despite being told repeatedly that they shoot around 310 stock.

It's completely stock, I've never even opened the gun.

I need it to be under 320 FPS, preferably around 310ish, and I'm looking for advice on what I can do to drop that number down, whether it be a weaker spring, or some other part I can buy and install.

I know there's velocity reducers out there but I'd sooner see if I can buy an internal mod, because I do plan on adding a silencer at some point in the future and with a velocity reducer on, I can't.

One way is to use heavier bbs, like .3g :D

A silencer may very well reduce the velocity by 20 FPS. The physics of why are probably mind-numbing, but every gun I've ever put a silencer on, from an MP5, AUG, G3/SG1 and M4 have all experienced this. All were stock guns as well.

Unless you absolutely must have less than 330 FPS to satisfy a club rule, I would just leave the gun alone. A lighter spring, like an M90 might just do the trick, if you need.

Unfortunately it is a club rule. (320 average is the limit.)

I'd sooner leave it alone but I need a gun I can use without breaking the rules.

Kind of irritating considering I've been using it for months under the assumption it shoots at 310.

Are they that sticky about 10 FPS? Most of the clubs I play with will allow for 10 FPS and if your a responsible player, it really doesn't make a difference between 320 and 330 FPS.

They're pretty strict about it, and it's shooting on the upper end of 330, closer to 340.

After doing some cursory research, Guarder SP85 seems like it'll do the trick, going to give that a try.

What weight of BBs are you using? If you're using .12s, you shouldn't have a problem, as most field limits are stated with .2g BBs.

Why dont you fill your profile with a clearer location so we can tell you about more specific local rules?
Or are we supposed to guess and read your mind?
Anyone who runs a field, and knows a gun is 100% 'stock' power would not be that anal.
So give us real details; ammo weight used. Ammo weight used for the testing.

It's not as if you boosted the gun yourself.

I use .2s, and the chrono testing is also done with .2s.

The field I play on is an indoor facility in Calgary, and the FPS rules are incredibly strict.

The limit is 320 average, even a result of 321 means you cannot use the gun.

could always take your spring out and cut it down a little bit

Run a couple hi-caps to wear out the spring a bit, then chrono.

Have you tried another chrono? 340 is crazy-fast for a stock gun (G&P excluded).

There is also the posibility of using a velocity reducer.
http://www.airsoftgi.com/product_inf...roducts_id=302
You won't have to fiddle in your gearbox. I read somewhere "If it ain't broken don't fix it". Personally I would mess with the spring and all since everything seems to be fine.

pull the trigger untill it almost fires. leave the spring cocked between games.
it will drop over time.

another option that I have used, go buy a container of softair .12g BBs. get a bucket of water(if your cheap and wanna re-use them) and burn though as much ammo as you feel comfortable with.

adjust your hopup, getting some usage out of it can help bring a new gun into regular fps.

just talk to the field owner. 10fps is nothing. I garentee you there is not a single person on the planet who could tell you the difference between a gun shooting 320fps and 330fps.