When purchasing 5.56 ammunition, it’s important to purchase the right kind. Federal Ammunition makes some very good products, but when I was first looking this up, there was a lot of confusion about the different product SKU’s. There was XM193, XM193BLK, XM193A, XM193AF, etc – even M193. Which should one get?

As it turns out, there is NO difference between any of the XM193 SKU’ed rounds. All of them are the same spec and manufactured 5.56 round. The ending designations are 100% to indicate the kind of packaging they come in. That is it.

M193 is also 5.56, but has different tolerances/specs than XM193. “M” by itself means that it must meet military specification (mil-spec) while “XM” means it does not. Mil-spec is very stringent and even a small thing out of specification can lead to tons of ammo being rejected. It is also usually illegal to purchase “M” specification (since it should be going to the military) – and reviews show XM shoots just as well in most circumstances.

So now that we know that all the different XM193 round flavors are the same round but in different boxes – what do those different ending designations mean?

SKU	Description	Appearace
XM193	XM193 5.56, 20 round brown box. 25 of these small boxes are often packed in a larger brown box to yield 500 rounds per case.
XM193F	“Packaging for XM193 is now done in Anoka, so a new part number (XM193F) was needed for FET purposes. THIS IS THE SAME ammo as XM193, and XM193C.” Example
XM193BK	XM193 5.56, Loose Bulk, 1000 rounds per case. Not as pretty as the boxed stuff as some note that rounds may get small dents during transit, but hasn’t been considered to cause actual firing problems. Example
XM193A and XM193AF	XM193 5.56 rounds packed in ten round stripper clips. Or AF with 900 per case: Example
XM193C	XM193 5.56 commercial package. American Eagle Tactical “Black Box,” 20 round box. Example
XM193CBP	XM193 5.56, commercial package. American Eagle Tactical “Black Box”, Loose rounds in 200 round bulk (value) pack. Example
XM193BL	XM193 5.56 in a 100 loose packed box. Example
XM193BX	XM193 5.56 in 20 rounds per box. Example
XM193ML1	XM193 5.56 in an ammo can of 400 rounds. Example
XM193BK420 AC1	XM193 5.56 in an ammo can of 420 rounds Example

All of these boxed rounds have the EXACT SAME kinds of rounds in them. It is purely a packaging difference. Take their word for it (slow loading due to it being on the internet archive). Here’s a copy of their fact sheet on it:

Links:

• Variations of XM193 and XM855: https://www.pewpewtactical.com/federal-m-vs-xm-556-xm193-vs-xm855
• Original discussion of different XM193 SKU’s: https://www.calguns.net/calgunforum/showthread.php?t=240167
• Lots of technical details on 5.56 vs 2.23: https://blog.westernpowders.com/2019/04/223-remington-and-the-5-56x45mm-military-nato-cartridge-and-chambers/