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.
Flatten Primers and Excessive Pressure out of Factory Hornady Amax?
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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
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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
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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
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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."
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Originally posted by PrecisionFirearms View PostOne was 3152556.
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.
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Originally posted by dammitman View Postlets 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?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
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Originally posted by dammitman View Postlets 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?
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.
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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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