If all you want to do is practice changing magazines than ranges don't really care. There is no safety rule regarding changing mags.
I don't know where you are but it should be fine. You'll get the odd look - no helping that but do talk to the range master and there isn't really any safety issues.
My original post was more aimed at practicing with more gear and tactics. If all you were wanting to do was practice changing out mags than that's easy.
The rate of fire, holstering and unholstering are pretty much covered by range rules... mag changes aren't really. Changing out a mag from the bench or from a magazine pouch really doesn't impact safety.
By the way. Airsoft has come a long way. A great tool for squad and close quarter drills. I'm not talking about your Big5 plastic $12.99 special. Anyways good luck to you.
"Shoot Safetly, Shoot Often and Share Your Sport." Jim Scoutten, Shooting USA
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