The barrel on my 442 is marked 38 special. It does not say +p. Is it safe to shoot +p ammo through my snubby even though it's not marked on the side of the barrel?
The 442 is not particularly comfortable nor controllable to shoot using any heavier load due to its light weight. I would not use +P for that reason alone.
S&W says any .38 Special revolver that has a Model # can safely shoot .38 Special +P ammo.
I think you are correct but the M442 is a fairly current design and most +P ammo of today barely reaches 18,000 PSI let alone the 20,000 PSI limits. Like I have said before, most current +P ammo is no more "powerful" than standard .38 Specials of the past when they were loaded to their limits. (pre-lawyer downgrades)I believe that only applied to steel frame guns.