Do you need to anneal your cases?

Whether or not you need to anneal your brass when converting 223/5.56 to 300 AAC/Blackout is a question that is very frequently asked.  I personally struggled to find the correct answer to this problem at the beginning of my 300 AAC loading journey.  If you check any online forum with a reloading topic section you will find those that tell you its an absolute requirement, and those like me that will tell you it’s not.  It’s honestly up to you what you want to do, but here are my reasons for thinking it’s a bit overkill.

  • Cost – The cost of the equipment to anneal your cases is going to run you at least a few hundred dollars.

    You can tell a case has been annealed by the “burned” look at the case shoulder and neck
  • Space – Annealing your cases requires heat which can pose a fire hazard so you will want to set it up in a safe space (pun intended :D).  The size of the equipment is also significant.

    This is one example of a case annealing machine you can buy online.
  • Abundance of replacement brass – The reason behind annealing the cases is to preserve life span of the case.  More specifically to prevent the case neck from splitting.  If you are shooting match grade brass then yes I can see the argument for wanting to preserve its life as long as possible.  Outside of that scenario, .223/5.56 NATO brass is so plentiful and cheap if you do split a case, you can throw it away without it hurting the wallet.
  • Time – Case prep is already time consuming enough, I really don’t want to add to the effort.

 

The best procedure for processing fired brass

This is the process I have come up with for prepping brass I bring home from the range.  I have tried to find ways to cut steps to save time but this is the best I can come up with.

  1. decap/deprime
  2. clean
  3. run through sizing die (obviously lube first if needed)
  4. check length
    • trim (if needed)
    • toss if too short
  5. clean primer pocket
  6. chamfer/debur

The cases are now ready to load.  Here are some of the consequences of skipping some steps:

Skipping step 2 will gum up your dies causing cases to get stuck and/or not size the case to speck

Skipping step 3 will cause the case to not be measured correctly

Skipping step 4 will at best cause your accuracy to be inconsistent, at worst you get rounds out of spec that can cause serious injury

Skipping step 5 can cause you to not be able to seat the primer all the way into the pocket

Step 6 is probably the only optional step in this list.  The reason I say this is because the consequence of not doing this step is mitigated based on the type of bullet and crimp die used.