i have a 12ga. H&R with a rifled barrel. i had it bore-sighted also. my question is... i want to sight in at 100 yds. should i start at 50 yds then go to a 100. or seeing how its boresighted can i just sight in at 100? sorry im not a gun hunter i always use a bow, i have guns but nothing with a scope on it until now. thanks

I'd start at 25, then 50, then 100. Just make sure you're close enough at 25 and 50 to be on the paper at 100 where you can finalize your adjustments.

Yep, get on paper at 25yrds, then go to 50yrds, for that gun I would go 2.5 inches high at 50yrds and that should put you dead on at 100yrds.