Downgrading a King Arms M4 FPS to 350ish

[Armen000]

Originally Posted by Scopedog

Springs are generally rated in m/s (meters per second). So an M100 or S100 spring would be 100mps or roughly 328fps.

Other components in the mechbox, inner barrel, hop-up, and quality of your air seal are going to influence velocity. Use the spring ratings as a ballpark estimate, not an absolute value.

if not already corrected, springs with an S before the number listed are not measured in m/s, for example, an M100 will get you around 330, you are correct, however an s100 will get you between 365-375 FPS. All spring brands have charts in order to pick out the right one, find them, and then find the right spring for your application

[ThunderCactus]

Also depends on the gun.
A systema M100 on a CYMA M4 might get you 300fps
On a fully upgraded king arms M4, will get you the full 365fps

[cetane]

I had to put a m90 in my m4 to get below 350. The m100 had me shooting mid 390's. Safe bet would be the m90. And jugglez great to deal with

[JLiang]

Yes, lots of people will tell you to get an M90 (or equivalent) spring. This allows you to have FPS hovering around the 300-340 mark, depending on the gun, which will usually qualify you for CQB skirmishes and provide a good platform for Field games. It's a Win-Win spring.

[Armen000]

Originally Posted by ThunderCactus

Also depends on the gun.
A systema M100 on a CYMA M4 might get you 300fps
On a fully upgraded king arms M4, will get you the full 365fps

yes, lets not leave compression out of this discussion aswell. If your gun has a loss of compression, the spring is the least of your worries, fix your compression problem then move onto a larger spring if need be! we dont want any broken gearboxes or broken gears for absolutely no reason!

[MatthewRyan]

Well i just chrono'd my KA today stock im getting 400 with .2, I would recommend the m90- to m95 ... i got a m95 havent installed it yet but fingers are crossed that it will keep it under 350 if anyone else is using a m95 could you tell me what your shooting at

[ShelledPants]

m90 = 90 meters (per second) = ~300fps
m95 = 95 meters (per second) = ~315fps