You will need frangible ammo, not only to protect the gallery...but probably to keep your insurance.
I would like to see old time shooting galleries set up as commonly as any other game rooms. The more people we get interested in shooting, the safer our gun rights are.
Don't know if anyone makes frangible ammo for .22 rimfire anymore, but PMC is making a line of centerfire frangible ammo...and they are a growing company, making their ammo in Boulder City, NV.
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www.pmcammo.com>
To maintain that good "old time" flavor, one could get the Taurus or Henry pump rifles...or perhaps that new Taurus M63 copy of the old Winchester auto.
The Taurus rifles have a lock mechanism that can control who uses it...insurance folks may like that feature..