5pm Mass St. Peter's Basilica

I was there a week ago and we were concluding our visit to the Vatican Museums and went straight into the Basilica. We weren't there for the Mass, the timing just worked out that way. It was held behind the High Altar and the barriers were put up at about the crossing. There were several openings in the barriers and the faithful would indicate to the security that they wanted to join the service and they were allowed in, to walk forward to the Mass. Many hundreds, like my wife and myself, stayed on the other side of the barrier. Many hundreds more continued their sightseeing in the rest of the Basilica. It works much the same when there is a service at a smaller altar. There will be security posted at the entrance of the chapel and upon indicating a request to join the service people are allowed through. That happened for us on the two other visits on subsequent days. It works very well.

I forgot about timing. In order to be safe it would be wise to allow 30 minutes or so to move through the security an into the Basilica itself at that time of day. Maybe less, on busy days probably more.

Is there a daily mass at 5?

Yes. The schedule for servicess in St. Peter's lists a 5pm service.