I had a Gen 1 Viper PST 6-24 that only lasted about 100 rounds on a Savage 110FCP in 338LM. There were several others here who had similar failures about the same time, all on braked magnums. The observation/theory was that they do OK with straight recoil, even if it's fairly heavy, but apparently they weren't built to withstand the reverse-recoil impulse that comes with a brake (or airgun, etc.). I do not know how the Gen 2 have fared since they came out, but I would not recommend a Gen 1, personally.