Question on drilling/tapping H&R 10 ga single barrel

[deadbuck]

I have an older H&R model 176 I want to be able to mount a traditional type scope on. I noticed the barrel thickness is much less where the shell is contained and thickens considerably past the end of the shell. Will the holes need to be drilled past where the shell sits for strength? I dont want a scout type mount half way down the barrel. Anybody done this or have pics from a previous project? Advice?