sentences:  APD SWAT adopted the full size Glock 21 Gen 4 due to mission-specific requirements that favor the .45 ACP round over the .40 S&W round.As of 2015, the department again transitioned to another 9mm handgun, the Glock 17 Gen 4, phasing out the .40 S&W Glock 22.The reason for this was modern 9x19mm bullet effectiveness and the fact 9mm puts less wear on the gun's components due to lower pressures compared to .40 S&W.