FPS of Prometheus MS150SP
 

It sounds like a dumb and obvious question I know, but I'll explain.

I've read a lot of places on this board that a guarder, systema, or prometheus (whether M, MS, or MS SP) at 120 will give you about 400 fps. However, there are a lot of other places on the web that claim a prometheus MS 150 SP is ~400 fps. I've read the spring chart and have seen what the MS120 SP shoots at, but, like I said, a lot of other websites have claimed different.

So... Anybody know first hand or for a fact what a prometheus MS 150 SP shoots at (roughly)?

Thanks,

Alex

Well, the rating is supposed to be in meters per second, so 150m/s is 492fps. I have a Laylax SP150 spring in my CA M24 and I get around 500fps, so............

Thanks for the effort but you didn't even read the thread title did you. Nor did you read the page you linked to but thanks for trying.

As stalker said, it should be just shy of 500fps

I commend Illusion for his efforts in making that chart and his work at getting those measurements, but I find too often people look at it (without reading the fine print) and use those numbers as fact, then are disappointed to find they get velocity readings much different than posted there. Illusion put a LOT of good parts in his test P90, including parts that increase velocity by tightening airseal issues and not just a matter of putting a certain spring into a relatively stock gun.

Thanks for the info, and I thought too that the rating would be in m/s. After all, it makes sense that a MS 150 would be 150 m/s and about 500 fps. But why is it then that a lot of other places on the web (like redwolf, or eHobby) list an MS 150 SP at ~400 fps?

http://www.redwolfairsoft.com/redwol...l?prodID=12952

http://cgi.ebay.com/Prometheus-Non-L...QQcmdZViewItem

http://forum.airsoftnebraska.com/ind...ic=499.msg4912 (just search "150" on the page and you'll see it)

Thanks,

Alex

I found the spring chart to be a good Spring-to-Spring comparison and generally useful for deciphering what ballpark a given spring will put you in. But after a number of builds, with a variety of components, I think that the only true way to see where your build is, with your mechbox, in your barrel/rifle is to chronograph it (with a real chrony, not a popcan).

The spring guides and m/s "labels" will get you close...at least within 30 fps or so...:D

I've had a M100 shoot 380+fps in one rifle and a Guarder "M120" shoot 350fps in another....but those are the exceptions rather than the rule.

the prometheus m120 is supposedly rated at just under 400fps, with upgrades it will put your gun over 400. i think that it would be the best choice to use cause the general rule of thumb, i thought, is that so long as the spring is rated under 400 fps, your mechbox will be ok. that is to say your mechbox will be under a lot of stress and will have a short life when compared to a spring rated just under 400. at least that is what mechbox.com says...

http://www.mechbox.com/site/inside-t...son-chart.html

I have a Prometheus 120 spring downstairs waiting to get installed into one of my MP5s, and supposedly this same spring put out 370fps in a TM M14. If a Prometheus 120 spring is *supposed* to be ballpark 390fps, I can't see how a Prometheus 150 spring would be the same.

I got 440fps on the MS150SP. I was some what disappointed as I got the same on a Systema M130 spring.

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.



Care to share the other details of that gun, particularly the length of the inner barrel and other internal upgrades? Barrel length plays a huge role as spring strength goes up. I once installed a Systema M120S in to a stock AK Beta-Spetz before which only put out 340fps. As soon as a 6.04mm 455mm (Ak length) inner barrel was installed, velocity jumped to over 400fps. That's over 60fps increase just by increasing barrel length.



I would imagine the Prometheus MS150SP spring hitting 500fps. In a properly upgraded gun (with air seal tightened up and made nice and efficient), that 500fps goal can be realized.

Keep in mind Redwolf also lists, for example, a Systema 120 at 300-400 FPS (that's a huge range!) and in my AUG I get 400. They list the Systema M100 at 260-300 FPS but in my custom M4 it's more like 360-370. Silly people.

Yeah, Redwolf does tend to have some crazy numbers at times...

From what I gather, they don't test across the same test platform. It's across various guns from all makes and sizes, and as a result, the recorded velocities will be just as wide.

It is some years back, but the gun was my old AUG. So the internals must have been a 509mm KM Ø6,04mm tight bore, a Systema NB cylinder set, ball bearing spring guide, aluminum piston with bearing.

Considering the performance of the gun on other springs, I think I might have gotten a Prometheus spring that was weaker than that specifications from the factory. The lower power spring I have from them (MS110SP), that I have in one of my other guns from them, perform like I would expect.

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.

Thanks,

Alex