Complex sentence: The Marines had posted a 4-11-2 record against NFL teams from 1921 until 1923, however after posting an 0-6 record in 1924, Dunn folded the team.
Split into simpler sentences: The Marines had posted a 4-11-2 record against NFL teams from 1921 until 1923. After posting an 0-6 record in 1924, Dunn folded the team.