A new airsoft company called "Angry Gun" has just released their Super Recoil Kit for gas blowback (GBB) M4 rifles. We already did a test for this kit, and it did not disappoint us with its performance. The blowback feel of our M4 rifle has significantly increased and was enhanced by this thing. Check out the specs:
Solid stainless steel construction
Designed as an upgrade for your M4's original recoil kit
Truly enhances and increases the blowback (recoil) force
Comes with a small L wrench for assembly and adjustment
This particular kit is suitable for use with WE M4 Series.