Several years ago the Feds passed a little known law. Sorry wish I could remember what it was called. Anyway, in, they authorized the feds to "deputize local agencies and equipment" when specific need arose.
The thought process was that many times bad guys don't just stick to one type of crime. Tax evaders are not necessarily non-dangerous felons. Many are involved in weapons/human/drug trafficking or organized crime. This was originally intended to back up RICO type investigations or Border Patrol/ Marshalls/State Police Agencies.
Different agencies out there recognized that assistance in planning, sharing of resources and man power was the only way to get even or a step ahead with an influx in violent crimes. Some may say that it seems like nonsense; however our country enjoyed 10 years of record lows in violent crimes across the nation since it was implemented.
Now ofcoarse violent crimes are in the rise again. Some say it is the influx of social destruction and economic wealth. Some say it is the change in tolerance in illicit drugs moving across the countryside which unfortunately has brought many addicts and violent crimes. It could be a cross of many problems.
Nonetheless, the government has encouraged all agencies to offer voluntary weapons classes. They weed out the weekenders and nourish the talented. They practice with a wide variety and scope of multi-talented and experienced groups of people. Let us not forget that the federal government is the feeder system for most post-military personnel. So the liklihood is that many of your accountant in the IRS having been in the military prior to becoming accountant is pretty high in ratio to private tax organizations.
So how is the Feds using this multi-tiered approach at reorganizing investigations that could turn into raids. They are equipping these personnel in order to make sure they can perform and defend themselves should the occasion arise. Does that mean that all IRS are expected to learn how to shoot an AR 15? No! It means that those who are involved in lengthy and dangerous investigations that cross over to other criminal investigations are equipped to protect themselves and other federal agents.
In other words, the IRS ain't sending pansies out to the field no more.