I also wish you a speedy recovery, it certainly must have been a frightening experiance.

I have also been struck by a rebounding slug. I got hit on the thigh by a .38 SPL wadcutter that rebounded off a log while rabbit hunting. The lead bullet hit hard enough to imprint the weave of the fabric of my trousers,. It didn't penetrate, only bruised. Range from the log was less than 10 yards. The ammo was factory WW Match ammo at about 770fps

I shot Handgun Metallic silhouettes for several years. As Match Director and Range Officer I had the occasion too follow up on rebounding slug reports. Most occurred at the 50 meter chickens. Some involved pieces of jacket material coming back. Some involved complete or partial slugs coming back, I don't recall a one that involved full power ammo, with an exception. The majority of rebounds were solid FMJ silhouette bullets. Low velocity was a key factor in kick back with the Pistol rounds.

The exception was our practice target. We found some very heavy plate 1"+ and set up some rigid mounted practice targets. We noted very early on the spatter pattern from the rigid 50 meter chicken was very different than the free standing chicken. Bullet spatter back almost to the firing line. We removed that rigid target and put up a hanging target and the problem was resolved.

I have a hard and fast rule. I never shoot without eye protection. Simple now, my old Geezer eyes require glasses to see. But back in my younger days and especially shooting sillhouettes I used eye protection. Our silhouette Club Mandated eye protection.