What size range are you talking about? Are you talking about something small that can be cored like going from an 8" hole to a 24" hole; or are you talking about going from a 4ft to a 8ft hole.
If larger, then could you notch the wall a couple feet above where you want to work, and then slide a steel lintel in?
I wouldn’t do it. I’d contact a contractor. The tools available typically dictate the method. I’m in a large metropolitan area with contractors that specialize in cutting and coring concrete.
If un-grouted and this was a project at my house, I would probably drill a series of holes thru the wall along the circumference then use a demolition bit in the hammer drill (or a sledge) to knock out the annular space. This assumes it does not have to be a super clean cut.
Off-topic but nineninenine made me think of something. There's a free dining & entertainment publication in NYC, and others cities as well, called Time Out. They used to have a little blurb called "Stories to Tell Tourists" They discontinued the feature before I could suggest saying these two building were permanently bent during Hurricane Sandy.
retired13, maybe my post wasn't clear. Although the magazine column was called "Stories to Tell Tourists", it really should have been named "B^!!$#!+ Stories to tell Tourists".
If you are positive on strength of the wall won't be affected by the opening (of the final size), I think it can be done by an experienced mason with these steps:
1. Make a template, and cutting a groove on both sides of the wall, using hand held saw.
2. Chipping out the bricks.
3. It will be much better if you can add ring bricks similar to miningman's photo to create arch effect in the finished product.
![[lol]](/data/assets/smilies/lol.gif "[lol] [lol]")
