Peek striker isn't the only way...it certainly is the easiest approach however that any rifle should be able to benefit from, very DIY friendly mod.
Having a valve open easier (many ways to skin this cat, from balanced valves, piloted valves, to other valve mods such as peek poppet and thinner valve stems/sleeved stem bores) requires much less strike than the stock valve, therefore less energy needs to be imparted into the valve to open it, thus vastly decreasing the noise generated upon impact of hammer to valve.
My marauder with a pilot valve has 25 lbs of force holding the pilot poppet to the seat while closed (the poppet the hammer strikes to actuate the main poppet), opposed to a stock regulated marauder valve that may have 150-190 lbs holding it shut. The required exchange in energy from hammer to valve to operate the piloted valve in my marauder is around .11-.12 FPE, where as a stock regulated marauder valve would require closer to .5~ fpe. 1/4 less kinetic energy required to actuate the valve greatly reduces the noise produced within the action during the shot cycle, and the momentum difference between the two arrangements is closer to double that, being roughly 1/8th less.
-Matt
