I bought a pack of slugs (federal) 12/70.
My gun is a mossberg silver reserve 12/76.

The dude in the shop told me that the 12/76 gun can take both 65,70 and 76 lenght.
I allways acepted this with regular shotgun amunition, but with one single bullet I fear it will hock into the edge in the chamber before entering the barrel if it's not the correct lenght.

I'm not going to risk my health by pulling the trigger and have it all going into my face just because of a idiot in a store not knowing what he talks about.

Is it safe to use slugs in a chamber longer than the cartrige?
My common sence say it won't get guided correctly into the barrel.

Any experts?