no.
while some person might have been able to kill like this in 1921, the average person was not able to kill like this. manufacturing improvements – including accuracy, reliability, ease of use, the low cost, and the ready availability of guns are obviously at play. so is too the complete gutting of gun laws.
it’s no coincidence that the modern nra arose after civil rights, and that the steady loosing of gun laws since the late 60s – including the brand new concept that the right to bear arms is an individual right – plays a direct role in these deaths.
gun technology and gun policy have changed, and as a result we see mass shootings. this doesnt happen in other countries, the timeline is clear as to why.