weee i got an m7 grenade launcher so i got some questions

1. when installed, it does compress the spring on the plunger down but only a little bit. i can still push it down more.
is this okay?
i'm guessing one way to check it is to fire a regular 30-06 round with the launcher installed. i would expect the rifle's action not to cycle.
does that sound right?
thank you.
goo.
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