Have a H&R Sidekick (huntsman), no, zero, nadda blow back.
Bought an after market Breech plug for $28.00
it has an O ring in the bottom of the primer carrier hole, the primer is a couple thousands proud when you drop it in, closing the action "squashes" it into the o ring.
The O rings are from Lowes 2.99 for 100.

Love this gun