Need to gear up for a civilian class in November, 3 days on SWAT/CQB tactics with mix of classroom, flat range and shoot house including low light work.  Problem is I only have basic accessories for AR-15 (two-point sling, light, plenty PMAGs and lots of ammo) so am looking for advice/opinions, pros/cons of different gear options to carry 3-6 PMAGs.  Current kit includes OWB holster 4 o'clock and pair of double mag pouches 8 o'clock from Raven Concealment for sidearm with light and pistol mags, so a battle belt and H-harness would conflict with that setup, plus conflict with muscle memory and costs more.  Welcome to the NFL, right?

Welcome to the forum!

What are the requirements for the class?

If you run a vest, moving the pistol up to the vest can work, but I feel like it starts getting in the way of pouches or you have to move it to an uncomfortable position. If you run a chest rig, It either gets moved to the far side, or in front of the mags. Neither place is good. I have used OWB and IWB with a chest rig and it works. I just suggest keeping the pistol more towards your butt and not towards your front. That way, it will stay out of the way of the chest rig. You could run it on a drop leg holster, you just need to have a very sturdy belt for it.

SKD Tactical and OP Tactical have great selections for chest rigs.

If all you are wanting to do is carry rifle mags, and not change your current set up, just get a chest rig that holds rifle mags.

For what it's worth, I picked up an inexpensive Condor chest rig (6 AR mags) and, while I wouldn't take it on deployment, it's held up very well for the past couple of years including a couple of carbine classes.
I added a holster to the right-side MOLLE straps and a Blade-Tech dual mag holder to the left-side MOLLE straps. It performed very well at the classes.
HTH...
Tomac

Appreciate your feedback and sharing your experience.  I imagined the vest getting in the way.  Am running the holster and mag pouches toward my butt as it is and was hoping that setup would work.  Was also on the SKD site yesterday looking at options for chest rigs.  Will try to stay away from a drop leg holster for now to avoid hiccups with muscle memory which is engrained at this point to that OWB holster on the belt.