Horse puckey ! You aren't seriously telling me you, Tikka or anybody else has any expectations of being protected from 60,000 psi gasses by a 1/32" thick plastic shroud are you ?
Nope, I'd say the plastic T-3 shroud would end up in your face but a steel or aluminum one may work just fine dealing with whatever gas gets into the bolt body from a pierced primer.
One advantage of the cheap Savage 110 action is that the back of the bolt is completely blocked by the bolt assembly screw.