In this paper, synthesis of very high molecular weight (VHMW) polyacrylonitrile-co-methyl acrylate (PAN-co-MA) polymers with weight average molecular weights of at least 1.7 million g/mole were repeatedly achieved on a laboratory scale using emulsion polymerization. The development of a hybrid dry-jet gel solution spinning technique for the VHMW PAN-co-MA enabled continuous spinning of 100 filament count tows, 100s of meters in length. Single filaments were analyzed and tested for tensile performance. Experimentally, the hybrid spinning method coupled with VHMW polymers produced precursor fibers with excellent tensile properties, averaging 954 MPa in strength and 15.9 GPa in elastic modulus (N = 296), with small filament diameters (5 μm). Results indicate a strong correlation between decreasing filament diameter, facilitated by high molecular weight polymer, and exponentially increasing tensile properties, using a hybrid dry-jet gel spinning process. Display omitted •Synthesis of copolymers with Mw ≥ 1.7 million g/mole was achieved.•A hybrid dry-jet gel spinning process was developed.•Reduced filament diameters were facilitated by very high molecular weight copolymers.•An exponential relationship between fiber diameter and tensile strength was established.•VHMW polymers produced precursor fibers with excellent tensile properties.