Instruct: Classify Amazon reviews into positive or negative sentiment
Query: 021 Viton O-Ring

I was having blow back issues with my 12gauge, and all the suggestions pointed to my gas ports, and the O ring. Now that I have replaced it, I need to get out and shoot again. Hopefully this was the fix. The only draw back with this product, is that you receive a "Costco" supply; more than enough for a lifetime.