Mossberg 835 Ulti-mag and slug question
 

Was planning a camping trip and wanted to take the 12 guage along for some skeet shooting and with some slugs for the when SHTF situation may occur. Want to take slugs but it has a 12 guage barrel that is over bored to 10 guage. Can I shoot slugs out of this or is it big enough to allow the slug to tumble and jam or something, or just have no accuracy.

I have an 835um. First, it is not 'overbored to 10 gauge.' it is overbored though.

It's stamped right in the barrel 'do lot use slugs'.

In the manual it specifies that using slugs will damage your shotgun.

That was kind of my question, what is the reason for no tusing slugs in it. Is the barrel just to big?