Hello Tayor,
Silver nickels will ID different, Anywhere from 5 up to Indian penny range. The reason is, The Magnesium alloy will break down over time. Not visually, but internally. The elements of time, weather, cold, heat? or whatever the reason a buried silver nickel's ID will eventually change, I believe the Magnesium alloy clauses this change and that's because the hard elements of mother nature creates this change.
That's my theory, No other coin in our history used Magnesium as an alloy. Eventually it breaks down internally if exposed to the harsh elements of nature....Scan your silver nickel finds and you'll see a difference, They will ID different.
Under the right conditions, Being is you're in the right area it is much easier to get an old Shield, Liberty, Buffalo or even an old non-silver Jefferson nickel than it is a war-time silver nickel. For those that put in the effort of mastering the recovery of deep nickel signals will find this true, Deep nickels are easy to find once the Explorer user gets dialed in.
I use ferrous mode, So deep nickels sound the same as a deep penny/dime signal. It takes time and patience to reduce your trash ratio, Eventually you'll get to were you're digging minimum trash and digging gobs of old nickels.
Get in the habit of shifting from cursor screen to digital, To check your nickel signal that is. I hunt in cursor and when I feel a nickel signal is beneath my coil quickly shift to digital, If it's a solid (6) I go for it. If it's a 5 or 7 I will dig it only if it's an extremely old site.
I can share more but it will only confuse you, For now see if this helps.
Take care, Paul (Ca)