Flatten Primers and Excessive Pressure out of Factory Hornady Amax?

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  • tasty_chicken
    Bloodstained
    • Jul 2015
    • 53

    Flatten Primers and Excessive Pressure out of Factory Hornady Amax?

    So I'm starting to reload some of my once fired Hornady cases and as I'm tumbling and inspecting the cases I noticed this ring around the brass. Is this a sign of excessive pressure? You can see the primer is flattened as well. What is really interesting is that this was not a reload. It was just a factory 123gr Hornady Amax.

  • cory
    Chieftain
    • Jun 2012
    • 2985

    #2
    Looks like early unlocking to me. What's your set up?
    "Those who sacrifice liberty for security, deserve neither." Benjamin Franklin

    Comment

    • LRRPF52
      Super Moderator
      • Sep 2014
      • 8569

      #3
      I've had brass that's been doing that for years. It's just the case obturation forming to the chamber. When I re-size, it's no longer there.

      Just looked at some brass that looked exactly like that after tumble polish.

      Since gas guns need slop, you will often see flat primers but nice dimples, which neither confirm nor deny excessive pressure, but are still good to pay attention to.

      What were your chrono readings and what's your barrel length?
      NRA Basic, Pistol, Rifle, Shotgun, RSO

      CCW, CQM, DM, Long Range Rifle Instructor

      6.5 Grendel Reloading Handbooks & chamber brushes can be found here:

      www.AR15buildbox.com

      Comment

      • tasty_chicken
        Bloodstained
        • Jul 2015
        • 53

        #4
        I don't have any chrono figures since it was just factory ammo, I will get chrono readings once I start reloading. It's a 50/50 split on the 100 rounds of brass I've shot so far that show this ring. If this is normal I'll re-size them as well and see what happens. Here is my setup:

        20" Black Hole Weaponry .264LBC Barrel. Rifle Length Gas System
        BHW Type 1 Bolt
        Ares Armor NiB Carrier
        Troy .750 gas block
        Rainier Upper
        Standard Carbine Extension Tube, H1 Buffer & Spring

        Comment

        • JASmith
          Chieftain
          • Sep 2014
          • 1620

          #5
          Getting several runs of factory ammo over the chrono will give one a better feel for how ammunition runs in his chamber.

          If factory ammo runs a bit fast, then the peak pressure is likely a bit above normal too.

          Reloads are likely to run a bit hot too.
          shootersnotes.com

          "To those who have fought and almost died for it, freedom has a flavor the protected will never know."
          -- Author Unknown

          "If at first you do succeed, try not to look astonished!" -- Milton Berle

          Comment

          • PrecisionFirearms
            Warrior
            • Apr 2011
            • 767

            #6
            We have seen 3 separate cases of this issue with Hornady Ammo within the last 3 weeks. All resulted in Broken Bolts. One customer had almost all of the box of ammo pierce primers on one of our Krieger Barrels. Sent the remainder back to Hornady and they replace it with 5 boxes of ammo. Another one broke 3 lugs off his bolt with cratered and flattened primers. All of them were able to fire AA and PF ammo with no over pressure signs. The one customer told me that a tech at Hornady stated they changed the powder due to not being able to to get the powder they normally use but somehow they were able to get the same velocity.
            "Precision - The Pinnacle of Perfection."

            Comment

            • cory
              Chieftain
              • Jun 2012
              • 2985

              #7
              Do you know the lot number?
              "Those who sacrifice liberty for security, deserve neither." Benjamin Franklin

              Comment

              • PrecisionFirearms
                Warrior
                • Apr 2011
                • 767

                #8
                One was 3152556.
                "Precision - The Pinnacle of Perfection."

                Comment

                • Drillboss
                  Warrior
                  • Jan 2015
                  • 894

                  #9
                  Originally posted by PrecisionFirearms View Post
                  One was 3152556.
                  For what it's worth:

                  I'm about halfway through a box of that lot number and haven't seen anything unusual on the brass. I chrono'd a round at 2610 fps through a Shilen 20" barrel the other day. This was about 50 fps faster than an average I had noted a couple months ago, but I attributed it to variations in my Chrony set up.

                  I did call Hornady yesterday and the tech I spoke with didn't know anything about any hot loads. He went so far as to put me on hold and talk to someone in their lab to confirm that.

                  I'm not picking sides or arguing here, just passing on information. A lot of people know more about these things than I do.

                  Comment

                  • dammitman
                    Warrior
                    • Dec 2012
                    • 647

                    #10
                    lets take this from the top i have several boxes i bought from cabellas with the lot number 3152556. i dont want to break any more bolts (i have had a past) should i shoot them?
                    Last edited by dammitman; 11-20-2015, 12:41 AM.

                    Comment

                    • LRRPF52
                      Super Moderator
                      • Sep 2014
                      • 8569

                      #11
                      Originally posted by dammitman View Post
                      lets take this from the top i have several boxes i bought from cabellas with the lot number 3152556. i dont want to break any more bolts (i have had a past) should i shoot them?
                      Can you pull one and measure the charge weight, take a pic of the powder?
                      NRA Basic, Pistol, Rifle, Shotgun, RSO

                      CCW, CQM, DM, Long Range Rifle Instructor

                      6.5 Grendel Reloading Handbooks & chamber brushes can be found here:

                      www.AR15buildbox.com

                      Comment

                      • Drillboss
                        Warrior
                        • Jan 2015
                        • 894

                        #12
                        I'll leave that answer for some of those folks I referenced above...


                        Just to be clear, LRRPF52's comment had not shown up when I posted this. He's one of those guys I was talking about.
                        Last edited by Drillboss; 11-20-2015, 03:04 AM.

                        Comment

                        • Klem
                          Chieftain
                          • Aug 2013
                          • 3507

                          #13
                          Originally posted by dammitman View Post
                          lets take this from the top i have several boxes i bought from cabellas with the lot number 3152556. i dont want to break any more bolts (i have had a past) should i shoot them?
                          In your shoes I would not risk it and return them for a refund. If the lot number is the same as PF has had issues with it is peace of mind to return for a refund. I would also wait until we get the chrono readings from Mr. 'Tasty Chicken'. Unconvinced if pulling and weighing the powder will be much help as manufacturers can use proprietary, blended powders in factory loads. If it's heavier than the heaviest safe load on the forum then that's certainly damning.

                          Flattened primers are sign of pressure but not necessarily over-pressure. Depends on the hardness of the primer cup used on that batch. Might be a soft primer on an OK load...or it might be over-pressure. Flattened primers are not a good sign regardless.

                          Comment

                          • kmon
                            Chieftain
                            • Feb 2015
                            • 2095

                            #14
                            Call Hornady about them with your lot # when you call. Have had ammo replaced from them in the past and they paid shipping back for their testing. Where do you think many of the ammo recalls are started a user having trouble.

                            Comment

                            • tasty_chicken
                              Bloodstained
                              • Jul 2015
                              • 53

                              #15
                              So here is the update. I wasn't able to get any chronograph data unfortunately. I went to the range and it was fairly windy and my chronograph got knocked over and broke one of the plastic light diffusers. I think I will go ahead and buy once, cry once and get a Magnetospeed.

                              I think what I am experiencing is specific to my rifle. I bought some different ammo with me this time around. All the ammo I used all showed the same flattened primer. The first was factory Hornady 123 SST. I first shot 4 3 round groups just to test the accuracy and I got pretty decent accuracy out of it. Like all the brass in my OP, all the primers were flattened and some showed the ring around the case and other did not.



                              I next shot some 100gr Wolf and same thing, flattened primers. I kept one of the cases in the picture below. After that I shot 2 groups of my hand loads I took from the Hornady Manual. Load 1 was 30.0gr of CFE223 with a Hornaday 123gr Amax bullet with CC450 primers. The second was exactly the same but with 30.6gr of CFE223. Same results, flatttened primers.



                              Until I get a new chrono I won't have any FPS numbers but seeing that this behavior is present across different types of ammo and relatively mild hand loads, i'm thinking that this is just normal behavior for my rifle

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