Update on breach seal replacement:
I recieved the packet of breach seals today from GAMO. Larspawn, I took your advice on the pushpin method for removing the old seal and it was out in 10 seconds. Surprisingly very easy. I went out to the garage and got the automatic transmission fluid and lightly lubed the new seal. It slipped in place fairly easy once I used the edge of a wooden spoon. I realized how beat up my old seal was once I had that new one in there. I dabbed the excess ATF off the new seal, popped the barrel back in place and voila, it fit perfectly
On the very first shot I clearly noticed a difference in the way the gun shot. I don't have a chrony but could tell the cans I was shooting were being penetrated with more force. It seemed the holes that were being made were cleaner cut too. I also noticed a little bit stronger recoil (kick) after replacing the seal. I guess this makes sense.
Anyway, the procedure only took about 5 minutes at most and it turned out to be what I needed I think for my velocity issue. Between the barrel clean and breach seal replacement I think my velocity is back up to where it originally was. Larspawn, thanks for all your help and advice. It was very useful.
Thanks guys.