I use regular foam plugs a lot. Depends on weather and if I want to hear other people.
Might I ask why you would not be ready for electronic protection? That seems odd. Electronic muffs work great. I can't think of any reason why someone would specifically NOT want electronics.
I get great protection by wearing foam plugs under slim electronic muffs. Hearing is close to normal and protection is excellent. Not needed for 22 rifle shooting though.