I took my 20.4 out for the first time to since getting a 22# RSA. After shooting I took the slide off to see how dirty it was to see if it needs cleaned. This is what I saw, That line between the slide rails on the frame. Since buying my G20 new this is its history. 1. Clean barrel and lube slide rail grooves 2. 100 rounds of UMC Rustington 3. Install extended slide stop and minus connector 4. 100 rounds of S&B (today) 5. 100 rounds of S&B with the 22# RSA (today) During the first 20 rounds of S&B with the 22#RSA I did get a light strike. I stopped, cleared, put the round back in and it shot fine. No other malfunctions.