I have my Father's Remington 521-T, which is in the same basic family.
In the 1980s I tried a WIDE range of ammo for it.
As expected some of the high-end (and expensive) target rounds from RWS, Eley, and Winchester performed very well...
But a real surprise was PMC Zapper, which turned in groups that were very close to the target ammo, and for about 1/3rd the price. I bought a bunch of bricks of that stuff and shot it for years.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.