If you don't need full pen, you might could use a PJP welded from one side, but you will still need to provide a slight bevel to remain prequalified due to the 1/2" material thickness.
ie. AWS D1.1 Figure 3.3 on page 77 (joint designation BC-P2 for SMAW or BC-P2-GF for GMAW & FCAW)
or on page 78 joint designation BTC-P4 requires a bevel only on one member and not both.
might be something you could use.