I know that some of them were soft (receivers).
Someone made have a serial # range,but I don't.
I would not get one unless you could see it was well used
and shows no signs of problems.
Just my 2 cents on B west stuff.

MRI

 

Off the top of my head.

Some Bwest receivers were made pre-ban. During the ban, that made them somewhat desirable.
They were originally made to assemble chinese kits on and quite a few rifles were "factory" assembled, as well as some receivers sold loose.

I believe just about all of them were not originally heat treated and were made of an alloy that was soft. The common problem was the rear tang rivets would tear the receiver rivet holes over a few hundred rounds. The trigger and hammer axis pin holes also had problems wallowing out. I owned a chinese kit gun that ate up the rear rivet holes in 120 rounds and junked it. I saw a friend's also self destruct. I chucked my Bwest gun when it self destructed more than 10 years ago.

Supposedly, the receivers could be heat treated to fix the problems. On a built up gun, that required the parts being disassembled off the receiver prior to heat treatment. At least I read reports of the receivers being fixed by a whole shell treatment. I wonder what alloy the receivers were made of, considering all the flats used nowdays untreated have no problems. The Bwest receivers must have been made of lower grade sheet metal and it makes me wonder if the heat treatment fixes reported were really reliable.

s & p