FPS of Prometheus MS150SP

[Spawn28]

A guarder 120 spring in a stock CA M15 shoots 405 FPS with a Guarder full tune up kit shoots 430 FPS just to give ya a Guarder Example

[Donster]

Originally Posted by ILLusion

The M14, in stock form, has some documented air seal issues. I have an M120S in mine, fully upgraded with 6.03mm 500mm tightbore inner barrel and it just shoots 398-400fps. I'm use to that spring pushing out 420+fps in my P90 or in properly upgraded Armalites.

well thats perfect for me since this will be my primary gun, i don't want it shooting over 400fps anyway. against field rules where i play at.

as a side note, would anew piston head in the M14 fix the air seal issues and thus increase fps. if so, what piston head do you guys recommend?

[CDN_Stalker]

Thanks Illusion for the info, that's helpful for my install planning.

BTW, has anyone tried the Madbull series of springs yet? I have three 110 springs in stock and have to set a gun up to test them through the chrony. I've been told by Hazard that the 110 spring tends to shoot 20-30fps higher than a Prometheus 110 spring. Looking for more info before I start testing, and once I get the testing I'll provide results.

[ILLusion]

Originally Posted by pizzainthemorning

Even if not a lot of people have a Prometheus MS150 SP, for those of you who specifically have Prometheus MS120 SP springs, does your gun shoot around 400 fps (and if you've got any upgrades or other modifications, please list as Illusion pointed out how the fps can increase as much as 60 with a longer barrel). I appreciate the info so far, but a lot has still been speculation, and "supposed to be" or controversial like possible mispackaged springs and losses in fps due to seal issues etc. Not that the data isn't valuable, and I don't mean to be really picky, but I'm still looking for that undeniable "this is a very good estimate as to the velocity". And yeah, I should just get it chronied then I'd know for sure.

There's no way anybody can give you a definitive answer. The best that any experienced person can do is give you a range, and if that person's smart, the berth of that range will be rather wide. i.e. "a Prometheus spring will give you between 450 and 510fps." There are way too many factors available to be able to honestly predict what your velocity would be. This is the exact reason why I have all the disclaimers on my spring chart - the data on there is never to be interpreted as "this is what velocity you WILL get with this spring."

Originally Posted by DONSTER 125

well thats perfect for me since this will be my primary gun, i don't want it shooting over 400fps anyway. against field rules where i play at.

as a side note, would anew piston head in the M14 fix the air seal issues and thus increase fps. if so, what piston head do you guys recommend?

That will help, but so will changing the cylinder head. The Guarder one seems to work the best, I've found. Even the Prometheus cylinder head seems to leak a bit of air, but not as bad as the stock one. The Prometheus air seal nozzle fits fine on the Guarder cylinder head, I'd change to that as well.

Also, check the connection between air seal nozzle and the hop up rubber - I've heard reports of air losses there as well, but I've never gotten in to inspecting that area on my gun. This is probably where I'm losing that 20fps or so. There are some forum posts across the 'net that go in to more detail on things that can be done to tighten up all the seals.

[Donster]

thanks Illusion i found right what i want on WGC... now you wouldn't happen to have said item in stock would you?


Package Includes:
- Stainless Cylinder Head
- Air Seal Nozzle
- Polycarbonate Ventilation Piston Head
- Super Lucid Chromium Plating Cylinder
- Polycarbonate Piston

Material: S303 Stainless Steel/Brass/Polycarbonate/Acetal

WGC #: Guarder Parts for AEG - AEG Series GD-PT-GE0346

[ILLusion]

Not in stock, but as usual, I can order it in for you. I have an order in progress right now through WGC - hit me by PM and we'll see if we can get that item added on for you. I can have it for you within a month

I would recommend you swap that piston head - it has known issues. There's a thread about that product somewhere in this forum.