What’s the difference?

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More often than not, on a Saturday afternoon, somehow we always seem to find ourselves spending an egregious amount of time in the local gun store looking for something else to make the wives scream, rant and rave!  Well….this Saturday was no different!!!  We found ourselves on the ammo isle at our local gun emporium (Adventure Outdoors) looking at the sale prices of .223 Remington and 5.56×45 NATO rounds.  Knowing how much we LOVE guns, the Firearm Gods sent us a gentleman who proceeded to ask us one of the most common asked firearm questions:  What’s the difference between the .223 ammo and the 5.56 ammo?  Needless to say, we talked his head off for about 13 minutes about the differences, both subtle and obvious.  Here’s a little of what we were fortunate to be able to discuss with this new shooter…..


This most common question is almost always asked due to one reason.  Many shooters will quite often use these rounds interchangeably in the same firearm….so what’s the difference?  At first glance, these two rounds of ammunition will look identical.  Although the cases of these rounds are in-fact identical, the bullets, powder, and chamber pressures used have stark contrasts. One important thing to note is that although it is perfectly safe to discharge .223 ammo in a rifle chambered for 5.56×45, the opposite is NOT true!  The reason being is that 5.56 ammo is loaded at a higher chamber pressure than .223 ammo.  So, firing a 5.56×45 NATO round through a firearm specifically designated for .223 Remington ammo can cause serious damage to your firearm.

While perusing the isles of your favorite gun store the next time, look closely at the ammo cases that contain both .223 and 5.56 rounds.  You will notice that .223 ammo has the designation Remington (from the original maker of the round) and the 5.56 ammo has the NATO designation.  SAAMI (Sporting Arms and Ammunition Manufacturing Institute) originally standardized the .223 round for civilian use while the military conglomerate known as NATO (North Atlantic Treaty Organization) standardized the 5.56 rounds.  The result was a slightly smaller chamber in rifles designated for only the .223 Remington ammunition.  Well….what in the world does all of that craziness mean?!?!?!?  It means that rifles chambered in 5.56×45 allow for the correct expansion of both .223 and 5.56×45 bullets while the chamber of .223 Remington rifles only allow for the expansion of .223 rounds.

If that explanation doesn’t tickle your fancy, below we will provide you with a technical exploded view of just how these rounds differ down to microns!   As we delve into the obvious technical differences between these two rounds, one of the most glaring differences is the “throat length” of each bullet.  The throat length is defined as the distance between the end of the cartridge neck and the point at which the rifling in the barrel engages the bullet.  The skinny of this is that, the differences in the throat length determine the accuracy of the shot.  Other measurements are included in this exploded view and can be examined at your leisure.


***If you are unfamiliar with the differences in kinds of ammo, the uses of specific ammo, or just want to learn more, PSA strongly suggests that you find and enroll in a reputable and comprehensive firearms safety course.   Firearm safety and the protection of 2nd Amendment rights is ALL of our responsibility.

We want to thank you for taking out the time to stop by our lane at the shooting range!!  We hope that you enjoyed your stay and hope that you stop back by early and often to catch up on all PSA updates!  We truly hope that we were able to hit the target, and if you ever have any questions please don’t hesitate to shoot them our way!!  We look forward to shooting the breeze with you soon again!!

And as always….remember to watch your six and stay low!!!

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