Cant help with the outdoor range, as I have only been to the Gun Store on East Tropicana.
I have been Jet Skiing numerous times though, all at Lake Mead.
I was last there a couple of months back in July.
For one hour it costs $95.
There is a $400 credit card hold, just in case you do any damage to the jet ski.
And you pay for any fuel you use during your time on the water.
I was virtually flat out for 50 minutes, and it cost me less than $20 for the gas I used.
Its great fun splashing around like a little kid, and well worth the approx. $115 it costs for one hour.
You can get very close to the Hoover Dam if you turn right when you leave the launching pad area.
There is a smallish gap in the rock which leads to the rear of the dam. Gives a decent view of the newish arch bridge too