I've sketched up some designs for this (hazard of being an architect, you tend to think in "plan sets"
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Looking at the economics (building area, ventilation, lighting, etc.) once you commit to 100 yards, really, 200 & 300 are not that much more expensive (if the site and building setbacks allow.
The "secret" is in ditching an "open" box, and going to individual lanes defined by RCP (Reinforced Concrete Pipe). RP is normally used for public storm drains. Then sections are rabbet jointed. Another virtue is that stock "collector boxes" already exist with matching joints.
Major downside is the price. Compared to HDP (High Density Plastic) culverts, RCP is very high-dollar. However RCP is going to be highly bullet resistant.
While you could "get by" with 48" ID, really, 72" ID is probably the ideal for lighting, target tracks, maintenance access, etc. Put your required ventilation at the butt end and it would be middling simple, mechanically.
Why pipe? Fair question. Ok, let's posit a 100 yard lane in an open box. You need, oh, 8' wide, and 10' of ceiling height. At a hundred yards, that's 8x10x300, or 24,000 cubic feet. If we need to change that air volume every 15 minutes, that's 1600 cfm (cubic feet per minute)--which is not a casual air handler.
Now, let's take a 72" culvert. Volume is π3² * 300. Which is ±8482 cubic feet. That only need 566 cfm to ventilate 4 times per hour.
At the "customer" end you can make the lanes as nice or as utilitarian as you care to. The butt end could be a simple CMU box with a baffle plate and a media pit. You'd want an 8x8 overhead door to get a skid-steer in. But, you could also pull butts maintenance on a lane-by-lane basis rather than having to shut the entire range down.
You could do this in an existing warehouse, if it had enough clear floor length. You could sand bed the culverts to limit the amount of demolition needed. Were the roof in good shape, you could even build a mezzanine over the shooting lanes and rent out storage space, too.