Winchester
It's actually a Winchester model 70 made for Sears and Roebuck.
Exact year cannot be determined from data given. 583.91 is not a serial number, but a Sears model number.
My best Guess would be to contact Husqvarna because they made it for sears. The Model 51 was made by High Stadnard using a FN Mauser action. The Model 51-L used the HVA action http://www.histandard.info/manuals/sears/cfrifles/index.html
It was produced between 1952 and 1956. It is considered one of the finest hunting rifles of it's time.
Yes, they have made many BARs in 270
yes. They also made a few engraved versions.
Remington never made the Model 4 in 270 Winchester.
Yes.
Antonie van Leeuwenhoek made a simple microscope that could magnify up to 270 times.
i have one myself, turns out they were, according to my gunsmith, made by CZ over in what is now the Czech Republic back in the 1960s or so. fantastic guns built on a solid action. apparently not all that common then or now.
270=270, |270|=270, opposite -270.