The OEM Ruger barrel....shot pretty bad compared to this GM. I ponied up the extra $$ at the time (15 years ago or so) for the "target" version, supposedly a better trigger, and the heavy hammer forged barrel. Still had to replace all the trigger guts with VQ, and the barrel, plus a few other minor mods to turn it into a keeper.
One of the best mods though was to radius the rear of the bolt... improved reliability and increased accuracy considerably. With the GM barrel I've run a brick through it using BC 25 round mags (when it was legal of course) without a single stoppage. That was with bulk CCI Blazer too