TYR Tactical

300 BLK Ammo Management Tip

John Hollister of SIG offered this tip to keep your 300 BLK ammo straight while at the range.

I get a fair amount of questions about ammunition management with 300 Blackout. One of the beauties of Blackout is the ability to use either Supersonic or Subsonic ammunition interchangeably. But how do you keep them straight?

I use two different looking and feeling magazines. I used to use both Aluminum and Polymer or 30s and 20s to segregate ammo types. Since Surefeed Magazines came out with the dimpled E2 magazines, I have gone to Supers in the E2 magazines and Subs in standard “GI” magazines, in this case a Brownells magazine. Both have Magpul followers and floor plates. You can see and feel the difference day or night. Shown is SIG 120gr SBR Supersonic all Copper and Discreet Ballistics 188gr Subsonic all Copper, both will fully expand in barrels down to a SIG Rattler length, 5.5” 1/5” twist. Another tip on magazines, when you clean you rifle, you should be completely cleaning your magazine.

Happy magazines make happy rifles.

11 Responses to “300 BLK Ammo Management Tip”

  1. Mike Dixon says:

    Good points. Or, if you are a cheap, ex military, wrap your subsonic mags with two wraps of 100mph tape at the very bottom of the mag. Cut the tape to about 1/4″. This will create a tactile difference between your regular mags. Also, I sued a similar technique for a mag of all tracers I routinely carried for directing fire.

  2. Gerard says:

    Ive pondered this question alot. I now defer to John Farnam. He says make a decision to own one caliber or the other but never own both a 300 and a 5.56

  3. Chuck says:

    I keep my 5.56 in P-Mags, and my .300AAC in metal Mags. To differentiate between sonic and sub, my sonics are ceracoated Foliage Green, the Subs left the origina color.

  4. Eric says:

    I’ve been using some of the new Sig subs. The funky shaped bullet ones in 208gr. Is Sig gonna still come out with that load in the LEO/Mil cartridge? The black case instead of nickel?

    I use color coded big rubber bands/silicone wrist bands to mark my 300 gun and mags. Yellow band on magwell of gun and yellow band on my mags loaded with 300. A second band goes on mag for supers above the first one.

    Gives visual and tactile differences.

  5. LouisCQ says:

    I keep my 300BO in Lancer clear mags. I use the 20 rounders for my subsonics. All my other mags are for 5.56, that way I know from feel and visually what’s what.

  6. Double D says:

    I use those rubber bracelets on my 300 mags. Same deal as tape method.
    Grabbed some off amazon cheap.
    They even make ones with diff. Calibers.

  7. Agent K says:

    I believe the article is about how to know the difference of ammunition in the SAME caliber (300BLK) not 5.56 vs. 300 BLK.