Do you have a mark on the muzzle? This may be because the silencer has come loose at some point during shooting. This is common at shooting ranges. Always check that the silencer is correctly mounted and securely fastened before starting shooting.
It sometimes happens during shooting at a shooting range that after a while, precision deteriorates. This is often due to the silencer coming loose as it heats up. If it is loose, you will get poor precision, and the bullet can leave a mark on the muzzle.
There is a function inside the silencer that should tighten it with each shot. Therefore, if it has come loose slightly, it can tighten again with the next shot.