only fixed magazine firearms are limited to 10rds or less, even then they are only AWs and its not illegal...only a feature of an AW, so a RAW can have a 20 & 30.
semiautomatic centerfire rifle can have a detachable 30rd magazine as long as it doesn't have other listed features are NOT AWs.
no part of large capacity magazine law states only AW use.
what range were you at?
on surrounded ground, plot, on deadly ground, fight.