What's the difference?
I see different type of peep, and pistol grip is different . . .
They take the same mags . . .
Do they have different barrels . . . heavier, longer on the 521?
I found this on line:
The 521T was advertised by Remington in 1951. Remington's top target rifle at the time was the Model 37 Rangemaster. The next step down was the 513T Matchmaster. In 1951, the 513T cost $46.30 without sights, $62.45 with Redfield 75 target sights. The 521T was a lower priced 513T, and cost $42.70 with a rear target sight only.
I recently bought a 513S which is the SPORTER VERSION of the 513 target rifle. In 1951, it was priced at $54.60, which is about $8.00 more than a Target version without sights, so I have been researching the 500 series Remingtons. (This would probably be equal to the Cooper or Kimber rifles today but in 1950's quality)
The model 37 Rangemaster was replaced by the 40x rimfire about 1955. In 1958, a 40x (now named the Rangemaster) cost $115.95 with sights, the 513T Matchmaster cost $60.05 with sights, and the 521T cost $54.95. The 40x and 513T had target rear and front sights, the 521 had a target rear and plain patridge type front sight.
Other Remington .22 prices in 1958 are as follows:
Model 510 single shot $23.95
Model 511 Scoremaster box mag. $31.75
Model 512 Sportsmaster tube mag. $35.95
Model 513T Matchmaster box mag $60.05
Model 514 Single shot $17.95
Model 521T box mag $54.95
This is a basic 500 series bolt action. Magazines are available from Brownells (a bit expensive at about $17, but may be found from other makers at about $10---check the internet). I found lots of them advertised, the 521, 513, and 511 mags are all the same---6 round.
Remington also suggested using the 521 as a hunting rifle, as some of their ads said you could easily remove the rear sight and mount a scope on it.
I had a 514BC as my first gun, and really liked it, but wished it was a repeater!