370 fps on a guarder sp100

[bob86]

as per tittle...

how???

[-=256=-Swerve]

Re: 370 fps on a guarder sp100

I've got a 120 doing 450 in my sniper right now

When I had ICS guns, I had Guarder M100 springs in two of my four upper gearboxes. In a well sealed and fettled hop unit they would come in at 360 and 375 in my long M4, and 320 and 340 in my short CXP

Ended up having to use M90 spring in two of the upper gearboxes for the long M4

[bob86]

Re: 370 fps on a guarder sp100

im sure i only had it at 300 with an m100 before thou, i thought i had kept the spring to one side, while the gearbox was waiting on new gears. yet the spring i thought i had kept was blowing at 390 so i chucked in the sp100 and was expecting 300 ish. maybe i need to worsen the airseal lol... the major prob is that i wanted 300 as its on my g&p stoner. dont exactly want it near 350

[-=256=-Swerve]

Re: 370 fps on a guarder sp100

A 100 will burst past 350 in a decent set up if you have any sort of barrel length

[bob86]

Re: 370 fps on a guarder sp100

well its over a foot

[TRH84]

Re: 370 fps on a guarder sp100

Sp90 needed.... :-)

[bob86]

Re: 370 fps on a guarder sp100

ffs, its a total pita opening the stoner back up, why are guarders so different??

[Caveira]

Re: 370 fps on a guarder sp100

I've read that one make of spring uses a power output based on 0.25s and not 0.20s.

Can't remember if this is guarder or not though.

[bob86]

Re: 370 fps on a guarder sp100

hmmm, knowing my luck of late, probably...

its not something daft like u get higher fps depending on which way the tigheter coils are....?

[Beef]

Re: 370 fps on a guarder sp100

no that should not make a difference, barrel length does however as i had a G&P zombie killer doing 320 and when i changed the front to a m16 full length it went up to 450

[Retroanaconda]

Re: 370 fps on a guarder sp100

Also gearbox length makes a difference.

For example a Star L85 gearbox compresses its spring about 10mm less than a standard V2 as the spring guide is approximately 10mm further from the cylinder head. This means that rather than getting the "normal" 330fps with an M100 it gives about 295-300. An M110 puts it up to 330-340fps.

Though I suspect in your case a mis-packaged or strangely strong is to blame.

[dave38x]

Re: 370 fps on a guarder sp100

Saying that though, L85 pistons have one more tooth on them than regular pistons.

Guarder do their springs to .25 gram ammo as well i think!

[Retroanaconda]

Re: 370 fps on a guarder sp100

Saying that though, L85 pistons have one more tooth on them than regular pistons.

Star ones don't, at least mine doesn't. Just a bog standard regular V2 piston/piston head. I know G&G (and Army) L85s have a different longer piston arrangement with more teeth.

Would be easier if springs and site power limits were all rated in joules, then you could just buy a 1J spring (for example) and be done with it. The use of FPS as a measure of muzzle energy is flawed, especially now that use of different weights of ammo in AEGs is far more widespread.

[dave38x]

Re: 370 fps on a guarder sp100

It wouldnt though, because the way springs are rated is highly unscientific, as is the tolerance on the FPS they give.

Similarly, the same spring with plenty of cylinder volume will give a heavier bb more energy as it has a longer time to accelerate in the barrel.

Not to mention that some guns leak air like sieves, and others (normally ones that have been tinkered half to death) are completely airtight, also rendering the "energy rating of a spring" useless.

And if a spring was a 1j spring and you stuck it in a Star l85, then you'd get less than one joule by definition.

FPS used in a calculation with ammo weight is the only way to establish muzzle energy.

[Retroanaconda]

Re: 370 fps on a guarder sp100

Spring tolerance/variance affects it whatever way you measure the power. But yes, calculating based upon the velocity and mass of the BB is the best way.

Sorry, I was suggesting that sites imposed a site limit of let's say 1J muzzle energy. The key point would be that when chrono-ing the weight of the BB would be input to the chrono and then it would calculate the muzzle energy for you and your yes/no vote would be based upon that.

A 1J spring can only produce 1J or less (although this assumes that the calculated power is based upon full compression to a coil-bound state). If you know your AEG is very efficient then a 1J spring will give you let's say 0.95J muzzle energy and away you go. If it's not so well sealed up then you could get away with a 1.1J spring that would give 0.9J out of the muzzle for example.

In practice it's unworkable due to the massive variance in springs as discussed, the assumptions I've made with regard to how springs are rated, and the need for sites to program the chrono for different weight ammo - which they're unlikely to want to do. My chrono has various memory settings you can choose from and it's fairly quick to change about, and it displays calculated muzzle energy but it's all added time and not all units have that function.