Is cutting spring coil really reducing FPS?

[Long_Bong]

Hi,

I m at 415 fps, target 400. How many coil should I cut (if it work)? It a JG spring use in MP5 J.

Thanks

Sebas

[The Saint]

Yes. Try 3/4 of a coil.

[Naglfar]

Just try small amounts and test after each cut.

Alternatively, measure the spring constant and calculate it using Hooke's Law

[kalnaren]

Won't the spring settle down to around 380-ish after some use?

[Crunchmeister]

Originally Posted by Long_Bong

Hi,

I m at 415 fps, target 400. How many coil should I cut (if it work)? It a JG spring use in MP5 J.

Thanks

Sebas

If the gun is brand new, just plink with it a few hundred rounds and the spring will settle to under 400. My JG MP5-J fired 360 to 370-ish when new, and settled to its advertised velocity of 340 after a few hundred rounds. My JG416 fired 410-420 new. After about 1000 rounds, it's 380-390.

[Long_Bong]

Tomorrow, I ll put 1000 rnd in it

Brand new spring indeed

[CDN_Stalker]

Sebas, flip the spring around so the tighter coils are at the piston instead of the spring guide, that should drop your fps by a decent amount.

[m102404]

Stalker,

What kind of velocity drops have you observed by flipping the spring around? Some people have told me that it can drop as much as 60-70fps.

[Syn]

Would flipping the spring lead to premature failure of spring at all?

[Long_Bong]

Originally Posted by CDN_Stalker

Sebas, flip the spring around so the tighter coils are at the piston instead of the spring guide, that should drop your fps by a decent amount.

It a JG spring, the spacing of coil is consistent on it

I did think about it

[CDN_Stalker]

Generally I've seen roughly 30-40fps drop in AEGs before. I had to flip my M24 spring around for the Muskoka game, as well as installing a non-bearing spring guide, got my 490fps gun down to 440fps.

[TokyoSeven]

Originally Posted by CDN_Stalker

Sebas, flip the spring around so the tighter coils are at the piston instead of the spring guide, that should drop your fps by a decent amount.

That does work very well, with consistent drops of around 30ish fps in most aegs. Well atleast most armalites anyways. Minus the one time I tried on a guarder spring and gained 20fps. We double checked, it was in properly the first time around. It still baffles me to this day.