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m102404 · November 17th, 2010, 15:51

The power ratings on springs are a bit wonky....

(I might be wrong with some of this)...The baseline was referencing 1Joule with a 0.20g BB. I always thought of it as the "TM base level" because their rifles all shot that hard out of the box.

This was approx 300fps...or theoretically 90m/s. So 110% springs were 330fps, etc... M100 springs were 330fps, etc...

But those numbers were based on different builds from what's "typical" today.
A LOT of builds now have bearing spring guides and tightbores installed...just some of the things that can "modify" the resultant FPS of an AEG.

There's even rough rules of thumb...such as add 7-10fps for a tightbore (that is going from a "stock" 6.08mm inner to a 6.04mm inner)...or add 10-15fps for a bearing spring guide (that is going from a "stock" flat TM spring guide to one with a bearing stack).

So....take a m90 spring and toss it into a stock "TM" mechbox and you're likely to see 300fps. Stick it into many of the other "stock" mechboxes and you're likely to see 330fps. Bad springs? Bad mechboxes? ...not really, just different parts inside.

The original post about the wild differences is still very valid....the M90 seems low. Modify S90 springs do have a tight pack of coils (IIRC)...that should go at the rear.

370 seems high from the KWA...I'd easily imagine 350-360 though with the parts in their mechboxes. But if compression and everything else is bang on you could hit 370.

I've also had the odd wonky spring that seemed way overpowered for what it was labeled...it could always be that as well....but I'd guess you got a wonky s90 spring.

November 17th, 2010, 15:51	#13
m102404 Tys Trader rating Join Date: Apr 2006 Location: Toronto	The power ratings on springs are a bit wonky.... (I might be wrong with some of this)...The baseline was referencing 1Joule with a 0.20g BB. I always thought of it as the "TM base level" because their rifles all shot that hard out of the box. This was approx 300fps...or theoretically 90m/s. So 110% springs were 330fps, etc... M100 springs were 330fps, etc... But those numbers were based on different builds from what's "typical" today. A LOT of builds now have bearing spring guides and tightbores installed...just some of the things that can "modify" the resultant FPS of an AEG. There's even rough rules of thumb...such as add 7-10fps for a tightbore (that is going from a "stock" 6.08mm inner to a 6.04mm inner)...or add 10-15fps for a bearing spring guide (that is going from a "stock" flat TM spring guide to one with a bearing stack). So....take a m90 spring and toss it into a stock "TM" mechbox and you're likely to see 300fps. Stick it into many of the other "stock" mechboxes and you're likely to see 330fps. Bad springs? Bad mechboxes? ...not really, just different parts inside. The original post about the wild differences is still very valid....the M90 seems low. Modify S90 springs do have a tight pack of coils (IIRC)...that should go at the rear. 370 seems high from the KWA...I'd easily imagine 350-360 though with the parts in their mechboxes. But if compression and everything else is bang on you could hit 370. I've also had the odd wonky spring that seemed way overpowered for what it was labeled...it could always be that as well....but I'd guess you got a wonky s90 spring.