Re: Silencer Foam problem
No. That is not normal. Sounds like your inner barrel is not straight or your silencer us not threaded on correctly.
You could remove the foam if you want. It's there to slightly change the report down range of each shot. Doesn't muffle the sound of your motor and gear box nor the piston slamming onto the cylinder head.
There are silencers that do not contain foam. Check airsoftparts.