Something not mentioned here is that the Mayflower Range website
information isn't accurate. The website states that:
Persons bringing loaded firearms to the range will be barred from shooting for one business day and may be cited. Firearms are considered loaded if shells or cartridges are in the chamber, magazine or cylinder. Removable magazines and cylinders may be loaded as long as they are locked separately from the firearm.
The sentence in Bold
above is not true. There are signs at the range which state the correct policy - No magazines, cylinders or clips may be loaded.
It doesn't matter if they're locked separately or not. They are quite adamant about that and you'll have to unload all magazines prior to entering the parking lot, definitely before approaching the range safety officer (RSO). I've hears that the RSO's will strictly enforce violations and make you leave the range, tho have never witnessed it myself.