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.
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