How much of a difference does match grade equipment make compared to standard, rack grade, issue rifles and ammunition? National champion CPT Freeman of the USAR Service Rifle Team shares his experience in competing with both.

By actual test, the difference in score between a top end match grade rifle with highly refined sights and trigger, ammunition, and shooting accessories (padded shooting coat, sling, glove, etc.) is less than 15%, even with a beat up, bottom-edge issue rack-grade rifle and ammunition with no refinements and no shooting accessories. It will likely be even less in most cases.

BLUF: Scores are earned by skill. Even the best match grade equipment can only account for the last few percentage points in the score.

The same holds true with handguns and practical shooting.
https://firearmusernetwork.com/race-guns-vs-regular-guns/

UPDATE

Since posting this video, All Army and other Service Conditions matches have held more National Match Course events requiring as-issued, rack-grade weapons. The scores demonstrated in this video occurred with competitors that had not practiced and fully prepared to shoot Across The Course with non-match equipment.

Since then, NMC events with issue gear have become more common at Service Conditions events and competitors have done a better job preparing. Using as-issued, rack-grade M4-series shooting issue ball ammunition (M855 green tip) winning scores are now in the 450-460 range. This is largely due to their practice efforts revealing how much (or how little or none…) sling tension will pull point of impact away from target center with an issue weapon lacking a float tube.