  We extend a magnetic braking (MB) model, which has been used earlier to
address the evolution of cataclysmic variables, to address the spin period
$P_\mathrm{spin}$ evolution of fully convective M dwarf (FCMD) stars. The MB
mechanism is an $\alpha-\Omega$ dynamo, which leads to stellar winds that carry
away angular momentum. We model our MB torque such that the FCMDs experience a
MB torque, approximately scaling as $P_\mathrm{spin}^{-1}$ at shorter periods,
before transitioning into a Skumanich-type MB torque, scaling as
$P_\mathrm{spin}^{-3}$. We also implement a parametrized reduction in the wind
mass loss owing to the entrapment of winds in dead zones. We choose a set of
initial conditions and vary the two free parameters in our model to find a good
match of our spin trajectories with open clusters containing FCMDs such as
NGC2547, Pleiades, NGC2516 and Praesepe. We find that our model can explain the
long spin periods of field stars and that a spread in spin distribution
persists till over 3 Gyr. An advantage of our model is in relating physically
motivated estimations of the magnetic field strength and stellar wind to
properties of the stellar dynamo, which other models often remain agnostic
about. We track the spin dependence of the wind mass losses, Alfv\'en radii and
surface magnetic fields and find good agreement with observations. We discuss
the implications of our results on the effect of the host FCMD on any orbiting
exoplanets and our plans to extend this model to explain solar-like stars in
the future.
