XL 650 Platform Locator Pin Obstruction

When re-installing the locator pin at station 3 during reloading ops today it would only insert about 1/16".  There appears to be a slight crescent-shape obstruction, as if a nut plate or similar piece within the platform had shifted out of alignment with the locator pin hole.  What's really strange is that the platform is a single casting with no such piece.  What could this be?  Am I missing something?

I'm relatively new to progressive reloaders, but have successfully reloaded several hundred 9mm cartridges.  However, today I was experiencing a sharp pop when pulling down the operating handle.  I can't imagine this (or anything for that matter) be related to an obstruction magically appearing in a platform locator pin hole.

The "sharp pop" was probably a slightly miss aligned primer or primer anvil that got loose. Or even a piece of .22 brass inside the 9mm case.  Something may have migrated to the locator pin hole.  See if you can lift out the obstruction with a small pick.

CR

Not sure what does you are using but my 9mm dies are Dillon and every time they push a primer out there is a pop from the primer pin remover. It is under tension, moves then resets.

I would first try steel pick to see if it is easily removable.  If not, I'd take conical punch, and open it up for button to fit in completely.  There's nothing critical in this area of platform.
AP

Second part of your question is more complicated.  Most likely it is related to plastic indexing ring underneath of platform, where it rides adjustment plate.  I'd check if screws on adjustment plate are tight.  If shell plate rotates freely, and stops at right position I would not worry about.  Also, Cecil is correct - primer punch would be the first indication of shell plate advancing to far or to short, and you can experience jump on anvil retrieval if shell plate wants to advance further, - this is also indexing adjustment problem.  You can try removing detent ball, and see if you still have same pop.  And no, IMO this has nothing to do with obstruction on station 3.
AP

Gentlemen,
Many thanks for your replies!
I ended up taking a punch, inserting in the locator pin hole, then firmly pressing the exposed crescent portion flush to the rest of the opening.  It was almost like it was a piece of flashing left from the casting process.  Odd thing is, I never before encountered the obstruction when inserting the locator pin or even seen any sort of flashing in the way.
With regard to the popping, I believe you're correct, in that it must be the depriming punch being slightly off center.  I always run my brass through depriming before cleaning; however, that doesn't mean the pin won't clip the side of the primer hole during reloading if off-center.