First time i had to replace orings on my hw100 was 4 years after the purchase. I then purchased oring service kit from a popular medium that had the good reviews those lasted 2 years now huge leak again. I am comfortable resealing the rifle myself but i would rather not if i can help it if they could last a bit longer that would be ideal. I dont suppose any of you gents/ ladies could recommend decent quality orings seller for hw100. Either way thanks.