Marlin 1894 Question

[Zappa]

What is this part protruding through an opening in the bottom of the receiver and what does it do ????

 

[cobblepot]

That's the bottom of the carrier rocker and I think it blocks the magazine when the carrier moves up.

 

[cobblepot]

this might help:

http://www.marlinowners.com/forum/gunsmithing-stickys/46737-basics-how-lever-action-works.html

 

[Zappa]

this might help:

http://www.marlinowners.com/forum/gunsmithing-stickys/46737-basics-how-lever-action-works.html

You're right, it blocks the next round in the tube from pushing out under the carrier as it lifts into alignment with the barrel.
Thanks for that link.