I just receives my first 1917A1 FA. Question...what can I use to seal the rear portion of the barrel? There is a a string that is worn out and leaks in it now. The front of the barrel has two "O" rings. I want to get rid of the "O" rings and seal it in the traditional way. What can I use and where can I find the proper seals and what kind of lubrication should I use? All help will be greatly apprecited. Thanks...KOG