Spring strength

[apmaman]

I got my gun chrono'd today and it was shooting at 308 fps and 13500 rpm. Sweet I thought but when I first got the gun I was just over 330.

22fps lost? what the?

How has this happened and any hints and tips to keep my spring in nice and strong!

[Caveira]

Re: Spring strength

225 rounds per second?

[Destroyer]

Re: Spring strength

LOL

225rps........... like a flamethrower


lmao

[Alfer]

Re: Spring strength

its obviously a typo, so stop taking the piss. Back on topic,

What might of happen is that after shooting you have left the spring compressed in the gearbox. not really a big deal to be honest as it equates to a 5/10m if your hop's dialed in

[jagillham]

Re: Spring strength

How do you uncompress it? Short of opening up the gearbox weekly?

[sj_asc]

Re: Spring strength

Fire a few shots in semi auto before you put it away, sometimes when you release the trigger on full auto the piston will stop half way in the cycle leaving the spring compressed.

[bravotwozero]

Re: Spring strength

Some guns now have a spring release button.

[Kodiak]

Re: Spring strength

The PSG-1 needs to be unwound before it's put away, but I don't know any other guns that have a feature the same on it.

I'm also curious about spring power. I have a TM P90 with an M100 spring hitting 350 FPS.

My TM M4A1 gets 320 on the same spring though, same for the G36C. Does the springs performance vary depending on the version of the gearbox?

[apmaman]

Re: Spring strength

Ahh, oops yeah its a typo... 1350

See I usually fire a few shouts on semi to make sure the guns clear and what not but still thats a bit of a drop.

Ive been looking at my gearbox and if I slightly pull the trigger so the air nozzle is over where the BB's would sit. Would that be it in its most uncompressed state. Rather than the nozzle being all the way back ready to get another BB moving. Sort of a half trigger pull just to get the nozzle to move and no more.

Edit:

Nah looking at the spring when I do that it looks even more compressed. Might be because it was a brand new spring and now that its worn in a bit its just dropped off some power.

[screwdriver]

Re: Spring strength

semi auto on alot of guns precocks the piston so will not release tension, on mine that do this ijust tap the trigger to get the box to part cycle till it just releases the piston .
why all aegs dont have somthing as obvious as a decocking lever amazes me

[apmaman]

Re: Spring strength

I think ICS M4's have that option in the way of the forward assist button, but I dont know for sure if thats the spring or for the gears. I'd imagine the spring though.

[screwdriver]

Re: Spring strength

decocks the spring by operating the anti reversal latch in the same way the g&g sa80 does

[sj_asc]

Re: Spring strength

I agree that there should be a decompressing latch or button as an option for all AEGs.

For most standard AEGs (excluding G&G/AA L85, PSG-1, KSCs and other precocking AEGs) the cut off lever flicks the switch block back to resting position soon after the final tooth on the sector gear releases the piston which cuts the power to the motor off, after cutoff there is going to be momentum (the gears aren't likely to stop instantly at the point of cutoff), but it isn't going to be enough to cycle the piston back to a fully compressed state, that goes for standard AEGs with a standard cycle/spring rate at least.

When you start going for faster rates of fire + lower spring rates there can be enough momentum to drive the piston back after power to the motor is shut off, which completes another shot or turning your semi auto into a to shot burst. The switch block return time can also be to blame for this.

For those going by the position of the airseal nozzle, the tappet is the first load that the sector is presented with, sometimes the momentum after cutoff is enough to pull the tappet back and engage the piston, which is why the airseal nozzle will appear locked back, it doesn't necessarily mean that the piston has the spring in a fully compressed state.
For those with sector chips (or tappet delayers), the tappet is engage sooner for most designs, so the chances of the nozzle being in the open position before the piston is engaged is even higher. Ideally the nozzle should be forwards so that the tappet spring is in a rested state.

Another approach to ensuring that the piston is reset every time with semi auto is "Active breaking"
With use of an "active braking" switch, the motor will be shorted when the power is cut off effectively acting as a brake by killing the residual electromotive force, stopping the motor and gear train very quickly.