Why the firearms for IRS agents? well i will tell you...
its for the CID, Criminal Investigation Division, which participates in drug bust along with ATF & DEA...an IRS CID auditor is often present to close out / file a tax return for those busted by DEA..it's not to have tax auditors pull a gun on you during an office audit.
you don't have to thank me for making you folks sound less ignorant (as if that's possible)