Remington 1100 12ga manufactured date

[Virginian]

I can't read the barrel code to where it makes sense, but that's not unusual. I have 3 barrels with no barrel code. From the serial number I would say late 1967 or early 1968. I have a '66, serial #3396**M and the 'L' prefix started in 1968.
I called Remington last year or the year before, and HD is supposed to be softer than the old Hevi-Shot, and they said it should be okay, but I still haven't shot anything bigger than #4 shot thru my fixed Full choke barrel. That somewhat rare 28" Full choke 3" barrel sure does feel good though. I have a Steel Shot barrel with tubes I use for Hevi-Shot and tungsten iron, and the big stuff for geese. The Remington HD shells are great as far as i am concerned. If you can find it, I also like the Kent Tungsten Matrix shells a whole lot, and I know they are safe in anything. And I shot some of the Winchester premium high density stuff and it seemed to work well also. I have not had satisfactory results with Bismuth, personally.
Good shooting.