According to this article MO is number 9 nationwide in gun sales.

https://www.libertyparkpress.com/report-top-ten-states-for-gun-sales-in-2023/

That's a disgrace.
We should be up there with Texas.

Populations...

Tennessee at 7.1M purchased 8.8% of its population.
Missouri at 6.2M purchased 8.4%.
Virginia at 8.7M purchased 6.7%.
Pennsylvania at 12.9M purchased 6.6%.

These 4 states stand out as having above 6%.  Texas was below 5% and California below 3%.

However, it is important to note this list is probably based on number of background checks. In some states the CHL exempts purchasers from a NICS check.  Ohio, Texas, South Carolina are examples where the most engaged population (CCW) is probably not showing up on NICS checks.

Of the states listed above 6%, none of them have a CHL that exempts buyers from NICS (Link).  Thus, we can probably guess there are other states with similar or even higher rates of purchases.  Guessing Ohio and Texas would be much more competitive.

ETA:

Check out the ATF's data on NFA registrations.  (ATF link).  Virginia has almost 4 times as many freedom lovers as Missouri.  Texas has 10 times.