Pulling the trigger would not fire the Hornady in the chamber. The bolt would not come back far enough to allow the unfired cartridge to eject. After much huffing and puffing with the vestigial operating handle on this big Browning Autoloading Rifle, a bright light shined into the open mag well revealed a surprising sight. The firing pin with the firing pin spring mangled but still on it was lodged between the back of the bolt and the bolt plate that constitutes the rear of the receiver. After more than 50 years of service, the oh so tiny firing pin retaining pin gave up the ghost, allowing the firing pin to slip out of the bolt causing a massive jam.

One of the original BARs made in 1965 when they were first introduced and only available in 30-06, the old girl lies completely disassembled on my workbench while I wait for a new firing pin retaining pin and spring to be sent to me from Browning.

At least you didnt have an AD with everything else being broke.

With the aid of two very good YouTube videos, I was able to disassemble, replace the firing pin retaining pin and reassemble the BAR.
I function fired a couple of magazines through it while sighting it in and it is still working. Back in action.

Browning BAR Assembly & Disassembly (Part 1)

Browning BAR Assembly & Disassembly (Part 2)

Borrowed an early model in .270 in 1979 that was a jam-o-matic. The owner later told me it took three trips to the shop and a visit to Browning to cure it. After that I never really had a high opinion of them despite it being a pretty gun.

I understand. Maintenance is not my strong point and I experienced jams that left me yearning for a simple bolt action rifle. One of the things I learned from the videos is that the early BARs like mine would crud up the gas cylinder and interfere with the smooth movement of the gas piston. Later generations had chrome lined gas cylinders for better reliability. The gas cylinder can be readily accessed for scrubbing out with a bore brush. Since I worked on mine, the cycling is much snappier now.