Get too much oil in the workings, particularly the bolt and you will have a mess on your hands.....Some 22 ammo is dirty and wont take long to foul things to where you get a lot of FTF and FTEs............I use a light gun oil applied with a rag then wiped all but dry.....If I am going to store a weapon then I will oil it some what heavy then wipe it out before I use it again.
I dont think it dampens the sound at all. The barrel runs all the way throught it. It is just a shroud. Buy extra mags for it you need them. I put a rail and red dot on mine. They are very quiet. A lot of cheap fun to shoot. I would like to try running some CCI Quiet 22 throught it. I think the decibels from it is down in the 68 range.
i went to the range today. shot the new ak and the MP5. The mp5 held great groups just a little to the right. i forgot to bring an allen wrench to adjust it lol it had two fail to chambers, but that is because i had my hand blocking the spring loader on the magazine