We tested two Shields...Recoil Spring Assemblies (RSA) was changed at 5,000 rounds on each gun. Then no change. One is a bit over 15,000 rounds (10,000 rounds on the same factory RSA) and the other at over 18,000 (13,000 on the same RSA). I personally fired 650 rounds of Winchester Ranger-T 147gr through one in an afternoon.
I can't wait to get mine in Sept for my birthday!