One more thing you may want to consider. Im not sure which Douglas barrel SMI uses but.....

Douglas offers Premium XX grade and Premium Air Gauge barrels too. The Premium XX is what Melvin uses on the NULAs and is well worth the extra IMO. Its only $10 more and if you have to wait for a custom twist....why not get a Premium XX grade.

As far as a 1-24, its probably fine in a quality barrel. Some OEM Savage barrels left a little to be desired due to rough tooling. Mine seems fine but it certainly isnt in the same league as a Douglas or a Pacnor.