So I took the plunge and ordered this spring to see what the hoopla was all about. I installed it in my full size rail gun and went to the range. Only put about 25 rounds thru her w/o any issues. The recoil felt the similar as my Wolff 16 lbs spring. The WC is rated at 17 lbs. And the spring comes w/ a WC Bulletproof spring rod. http://shopwilsoncombat.com/Flat-Wire-Recoil-Spring-Kit-Full-Size/productinfo/614/ Here are some comparison pictures between the WC vs. Wolff spring, and WC BP rod vs. EGW rod. The WC rod is proprietary and must be use w/ the FW spring. I'm going to run this set up for a while. Pretty happy with the purchase.