If the Remington is a Pietta, the mainspring will be much stiffer than an Uberti, or even your car's suspension. They can be thinned, or even replaced with a lighter spring, but as the previous responder mentioned, you have to have enough spring to prevent misfires.
The tension screw on the Remington will adjust the tension up to a point, but loosening it too much will actually make the spring stiffer again due to the curve and its effect on the apparent length, it will rub on the inside curve of the hammer and feel harder.
The Remington repro cartridge guns (1875 and 1890) also have heavier springs than the Colt types, but not as heavy as the cap & ball. However if you have a Pietta, an Uberti spring may not fit well. Some shooters put in a Colt spring, even with the now unused screw hole, they will work in a Remington.