For: Guarder SP170 AEG SpringProduct Information:
To the writer of the first review, please do research before you ever write anything again, as what you said is completely bogus and can be qualified as total misinformation.
First off, this type of spring should only ever be used in AEG's that have been extensively upgraded to handle the massive spring tension, and also preferably to where they are semi-auto ONLY. The FPS you get from a spring like this necessitates the use of a very high torque motor as well.
Honestly this level of spring is best used in Bolt action rifles that are capable of using AEG springs because it will up the FPS of even that to over 500 fairly easily.
THE LAST THING YOU WANT TO TRY TO MAKE IS AN AEG WITH FULL AUTO CAPABILITIES SHOOTING AT 550FPS, YOU WILL HURT SOMEONE.
That being said, spring is pretty standard, does what its designed to do fairly well!
Lasts a while
Will give your DMR platform a very substantial FPS increase, Just make sure to be safe with that kind of FPS
Meant for very specific usage due to the level of velocity it gives any type of BB you will use.