  Theoretical predictions for the cosmic antiproton spectrum currently fall
short of the corresponding experimental level of accuracy. Among the main
sources of uncertainty are the antiproton production cross sections in cosmic
ray inelastic interactions. We analyse existing data on antiproton production
in $pp$ scattering, including for the first time the measurements performed by
the NA49 Collaboration. We compute the antiproton spectrum finding that in the
energy range where data are available (antiproton energies of about 4-550 GeV)
different approaches lead to almost equivalent results, with an uncertainty of
10-20\%. Extrapolations outside this region lead to different estimates, with
the uncertainties reaching the 50\% level around $1$ TeV, degrading the
diagnostic power of the antiproton channel at those energies. We also comment
on the uncertainties in the antiproton production source term coming from
nuclei heavier than protons and from neutrons produced in $pp$ scatterings, and
point out the need for dedicated experimental campaigns for all processes
involving antiproton production in collisions of light nuclei.
