Good question. But if you really want Milsim, we always suggest following the allowable age for young people to be drafted or volunteer to serve in the military in the country where it is being organised. This usually means minors are not allowed to participate. Airsoftology talks about this and other topics such as burst-fire and sidearms for airsoft medics.

"Tippmann Mail Call:

1:52 - Should teenagers be allowed at major Milsim events?
4:37 - For semi-auto only airsoft fields, should burst fire be allowed?
7:55 - What is the best sidearm for a Medic in airsoft?

10:55 - SW Airsoft -BALLAHACK BATTLE ROYALE | Part 1 | Ballahack Airsoft | Zoomcam 2"