Slide overtravel|Winchester Shotguns|Forum|Winchester Collector

This gun was purchased by my father in year 1936 approximately brand new. It’s a 20 ga mod 12, and I purchased it from him when I was 15 yrs old.

As long as I have owned the gun, the slide would go forward beyond where it should go. I wrapped tape around the mag tube to prevent it going further than where it should.

I read somewhere some time ago that there is a part missing that should prevent this problem. My question is what is the nomenclature, and where can it be obtained? I haven’t fired this gun for several years, so out of  sight, out of mind. I’m now 84 y/o, and would like to fix the gun, even if I never use it before passing it along to my kids. I figured that someone on a forum would know this gun, and what is missing. 

It’s not a collector item for I re-blued it, and refinished the stock over the years. It really doesn’t matter what the value. It’s a family heirloom, and will continue as such. If someone can help me out with this problem that has existed for 85+ years, I would certainly appreciate it.

Thanks in advance,

Fred South