Angel Custom Enhanced Recoil and Hammer Spring Set for ISSC M22 SAI BLU Lonewolf & Compatible Airsoft Gas Blowback Pistols (Type: 140%)

"Put this in my VFC/Cybergun SAI M&P 9. I use the co2 mags and this spring needed to be shortened so the slide would lock back. Not a big deal as I new this would be the case based on other reviews. The recoil is extremely snappy and fast. Allows follow up shots to be quick. Racking the slide/releasing the slide is extremely quick/snappy as well. I tested this w/ the propane magazine and on a full charge I could get the slide to lock back, but I have not tested a full propane mag w/ bbs, only a few shots. Would probably only recommend to use this if youre running co2. Overall very pleased.

"Was looking for an enhanced recoil spring for a KJW KP13, which is roughly based on a glock 17. I had replaced the standard outer barrel with a 14mm CCW threaded outer barrel. However, I found that the stock spring wasnt strong enough to support a suppressor.(It would get stuck mid way through the racking motion)

Bought this hoping that the KP13 was similar enough to a G17 that it work. I found that the enhanced recoil spring was so strong, that the slide wouldnt go far enough back to cock the hammer. I decided to shorten the spring by cutting off 3 rings. It now operates properly with a CO2 mag, but not with green gas.

Long story short, this can work for a KP13, but modification is required. As the previous reviewer stated, you should plan on using this with CO2 or HPA for proper operation.

All things considered, it was a cheap fix and I learned a lot about the mechanics of the KP 13. 5 stars if you have the patience for it.

"So just got this in today, installed the two springs in my we g34 and after a bit of testing I found out that this shouldn't be used with the standard propane/green gas set up, it's more for a CO2/HPA set up cause the slide doesn't have enough power to activate the hammer spring in standard form