On a side note.. the GUARDER APS 2 spring M170 generates some unhealty fps....aka 680fps with .2g...... The M150 (the lowest available) might be a better choice or stick with PDI or Laylax springs

LOL
awsome

lol. I'm glad you finally got your package and everything set up.

You should've seen the Guarder SP170 AEG spring that WGC originally sent me by mistake... that thing was SOOOO STIFF that i couldn't even compress it with my hands

Hello everyone. I got systema M120 on my M4 and it is shooting 435fps and on my other M4 is SP110 and it is shooting 425fps? It left me wondering if I got a mislabeled spring or this is normal?

A 25% variance is not uncommon and is fairly normal.

Again, that is dependent on a lot of factors, including gun platform, other upgrades, BBs used, chronograph used, even temperature can affect results.

Again, my chart is only used for comparing one spring against another and not an end-all-be-all solution that determines EXACTLY what FPS you will get.

Hi all,
ILLusion, that's a great chart you got there, the Systems M120S was spot on my AEG, 418-424 fps, however when I tried the Prometheus 150 it was 445-449 fps, and the Systema M130 was chronoed at 470-474 fps!!
Another question, which I hope any of you experienced gurus can answer is the "sweet spot" fps for a 0.25g bb, which is:
For instance when I used the Prom 150 and the systema 130, the 0.25g was not accurate at all, it was swinging left and right, but when I used the Sys 120s, it was much straighter. The bb's used were KSC and Excel, the chrono used is the Combro MK4. Thanks for any valuable input.

Sorry to mention before, all the chrono test were done using 0.20g bb's.

where did you find a guarder aps 2 170% spring???

I got it for him.

And it's M170. Not 170%. Those are two totally different ratings.

RE: Illusion
 

ok since im new at this, could you explain the difference to me?
Wingman

Just look at my spring chart and compare the velocity of an M120 to a 120%.

"M"-prefixed springs are generally measured in metres per second.

Try the heavier .30-.43g bb's.

Thanks, damage.

i put it up in other threads last year, but just to add
My SR16 had a 6.04 tightbore, systema duracon piston head and a PDI 150%
it chronied with 460fps on .20g

after working the spring in(burning through bags of BBs and leaving it compressed for weeks at a time, its down to 400fps.

Other threads have discussed the PDI 150% but its not mentioned in this thread.
Illusion can prolly sum it up for people who refrence this thread and not the others. Something about PDI 150% and PDI 150% Pro getting mixed up and essentially having a 190% in your gun.

And that's why I always recommend Prometheus MS110SP springs over PDI springs. Even if you were to get the velocity you were looking for out of the PDI spring, Prometheus springs, I've found, just shoot more consistently than PDI springs.