Hello Sean,
I am not that good at physics, so I apologies if my idea does to fit to the purpose.
I would suggest loosing the "For" loop. It is my experience with Mathematica, that whenever you use loops, there is a more clean way of doing things. In your case, I might consider using Recurrence Table, and then merge the lists using Transpose. Then you can plot the data via ListPlot. :-)
For instance:
kp = 40;(*Spring constant*)
kc = 250;(*Spring constant*)
deltaT = .03;(*Time Step*)
m = 1;(*Mass*)
iini = 0;
ilast = 25;
nini = 0;
nlast = 300;
X = 0;
V = .01;
F = 50;
T = 0;
lstTime =
RecurrenceTable[{time[n + 1] == time[n] + deltaT, time[1] == nini},
time, {n, nini + 1, nlast}];
Hope it helps, or that someone can help you with a better answer :-)
Edit: As I am sure you recognized, I left out writing the "V[n+1]". Simply because I fear I would write the expression wrong when I do not know the physics behind it in detail. So it is for you to fill out :-)
Edit 2: I completely forgot to say that RecurrenceTable allows for more systems of equations than just a single one. In which case you will not need to Transpose prior plotting, I presume. Check out
http://reference.wolfram.com/mathematica/ref/RecurrenceTable.html.
