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Posted: 8/6/2018 10:08:58 AM EDT
Update further down the page with pics of fired primers separate from case. Some are flat.
308 Win AR-308 20" match barrel 168 gr Nosler HPBT Custom Competition AA2230 1x fired .mil surplus 7.62 brass, sorted by headstamp Max velocity per Accurate Arms 2,701 fps COL is a little too long and scraping the front of the mag on the inside. Needs to be adjusted shorter. Moderate crimp Thoughts on these primers? There's a little primer flow and they look flat to me. Two photos per batch - one with flash and one without: 41.2gr 2,583fps - 2,578 - 2,609 - 2,609 - 2,624 
41.5gr 2,624 - 2,656 - 2,645 - 2,645 - 2,604 
41.6gr 2,614 - 2,645 - 2,661 - 2,682 - 2,609 
41.8gr 2,614 - 2,661 - 2,645 - 2,666 - 2,656 
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Posted: 8/6/2018 10:19:57 AM EDT
[#1]
They are fine.
I was loading .308 with 168gr Sierra HPBT and they wouldn't chamber in my PSA AR because the ogive was hitting the rifling. They fit in the Magpul mags. COL was a bit over SAAMI and they would still chamber fine in my Remington 700. I had been loading them that way for a while. 
If you were overpressure or over gassed, you would see ejector scuffing or extrusion. My PSA was severely over-gassed with the can on. An adjustable gas block fixed that. I even pulled bullets and measured powder for sanity and the Magnetospeed also said I was safe. |
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Posted: 8/6/2018 10:36:36 AM EDT
[#2]
Quote HistoryQuoted:
They are fine. Hornady Black in 6.5CM, 140g HPBT look way flatter in all three of my rifles...two bolt guns and one AR10. On the primer flow my first thought is the size of the firing pin aperture. |
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Posted: 8/6/2018 10:49:58 AM EDT
[#3]
Quote HistoryQuoted:
Agree. Those primers still have some nice rounded edges at the perimeter of the pocket, so they don't even look as flat as a lot of factory ammo I've seen create in a 6.5CM. Hornady Black in 6.5CM, 140g HPBT look way flatter in all three of my rifles...two bolt guns and one AR10. On the primer flow my first thought is the size of the firing pin aperture. |
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Posted: 8/6/2018 10:52:50 AM EDT
[#4]
Reading primers for pressure is an inexact
That said your primers are fine. What you look at is where the edge of the primer meets the edge of the primer pocket. Your primers are still rounded, if it flat there then I would be concerned. But good on you to ask. 
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Posted: 8/6/2018 10:54:28 AM EDT
[#5]
Disclaimer: I am not a huge proponent of reading primers, let alone me trying to read other people's from internet pictures.
That out of the way .... my only two cents are, if you are going to attempt to read primers, make sure they are seated properly, make sure the primer pockets aren't loose, and make sure you aren't oversizing brass headspace for the specific chamber you are loading them for. Do these three things, and you might get some useful tells from primers, might. If those were my reloads, and if I was attempting to get a tell from them for myself, I would say they look fine as far as flattened, for me. That typed, it's hard to tell from pic, but looks like a couple may have backed out, or weren't seated well to begin with, could be the angle of the picture, and also see some what would be concerning to me swipes, which could be from this load or prior use .... and something could be up with either the load or the first three things I mentioned or the firing pin on a few, I don't know, ymmv |
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Posted: 8/6/2018 11:15:33 AM EDT
[#6]
Primers don't look flat, little case head swipe at the upper charges. Just to be aware, the Western 5.0 manual is using win brass, wlr primers and 24 in barrel. How was the accuracy with the differing loads?
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Posted: 8/6/2018 11:28:49 AM EDT
[#7]
Quote HistoryQuoted:
Primers don't look flat, little case head swipe at the upper charges. Just to be aware, the Western 5.0 manual is using win brass, wlr primers and 24 in barrel. How was the accuracy with the differing loads? Some of the case heads are messy from what I can only assume were machineguns from the .mil, but I'll pay more attention on the next set since I have to do shorter COL anyway and start again. Groups look to be under 1 MOA (hoping for .5-.75"), but it was really sloppy shooting on a picnic bench. I was shooting with a heat index of 103* and pouring sweat just sitting there  . Each heartbeat moved the POA about 2" at 100 yds and I'm not good at timing beats yet. So they show up in one of two 1" places
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Posted: 8/6/2018 1:43:43 PM EDT
[#8]
Looks like snug headspace and moderate pressure (round edges and not backed out), loose firing pin to aperture fit.
If no indication of gas system timing issue, there may be another node to work up to. |
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Posted: 8/6/2018 9:01:08 PM EDT
[#9]
No they look fine...I don't use primers for judging loads much, just a general indicator that you may be getting close...These are close to max pressure, different caliber then you have but within a grain or two of max for the temp they were shot at...The ejector mark is a better indicator....This was 101 grains of RL-33....
 Attached File |
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Posted: 8/6/2018 9:27:19 PM EDT
[#10]
Forget the primers and pay attention to the velocity.
If Accurate Arm's maximum velocity is probably fired from a 24" barrel which is automatically 100 fps. faster than your 20". If they say 2701 fps from a 24", that translates to 2601 fps from a 20". You loading military surplus brass adds another reason to be cautious. Military brass (.308/7.62x51mm) can't safely achieve the same velocities that Winchester commercial brass can. As an absolute maximum 2600 fps. should be a known maximum using commercial brass. I would subtract an additional 50 fps. when loading Lake City. My maximum loads fired from a 22" M1-A in Lake City braas using 168's run 2500 fps. Go faster at your own risk. |
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Posted: 8/6/2018 10:02:17 PM EDT
[#11]
Look ok, knock them out of the case and look at them, is there a ridge around the top edge, I would say no, but if you're not sure have a look after
you punch em out and got em in your hand. |
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Posted: 8/6/2018 10:07:18 PM EDT
[#12]
(deleted)
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Posted: 8/7/2018 9:18:33 PM EDT
[#13]
Quote HistoryQuoted:
Look ok, knock them out of the case and look at them, is there a ridge around the top edge, I would say no, but if you're not sure have a look after you punch em out and got em in your hand.  Attached File Attached File Attached File Attached File Attached FileLooks like I need to dial it down. |
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Posted: 8/7/2018 9:28:26 PM EDT
[#14]
Quote HistoryQuoted:
Forget the primers and pay attention to the velocity. If Accurate Arm's maximum velocity is probably fired from a 24" barrel which is automatically 100 fps. faster than your 20". If they say 2701 fps from a 24", that translates to 2601 fps from a 20". You loading military surplus brass adds another reason to be cautious. Military brass (.308/7.62x51mm) can't safely achieve the same velocities that Winchester commercial brass can. As an absolute maximum 2600 fps. should be a known maximum using commercial brass. I would subtract an additional 50 fps. when loading Lake City. My maximum loads fired from a 22" M1-A in Lake City braas using 168's run 2500 fps. Go faster at your own risk. |
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Posted: 8/7/2018 10:24:57 PM EDT
[#15]
Quote HistoryQuoted:
That isn't how I understand .mil and commercial brass to differ. More like they can achieve the same velocity but due to the increased thickness of .mil brass, it will take less powder to do so over commercial. Winchester or Lapua brand brass can usually allow you to get between 2650 to 2700 fps. Using shorter barrels reduces velocity around 25 fps for every inch shorter than 24". Two things are going on at the same time. Smaller internal capacity spikes pressure limits quicker with less powder. Because you have less fuel to drive the bullet, maximum possible velocity suffers as well. |
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Posted: 8/7/2018 11:43:19 PM EDT
[#16]
Those are not particularly flat. It's not great but my guess is you are okay. It is a gas gun, though, so some extra caution is warranted.
If I said 2600 fps was a hot but safe load fired from a 24" barrel, your 20" barrel should generate only 2500 fps. Barrel geometry has an effect on pressure profile (tight/loose bore, throat length,...) , so leaving some margin is wise. The above is all voodoo - reading primer flatness and cratering and using velocity as a gage for peak internal pressure. Run QuickLoad, instead. Consider buying a primer punch so you do not lose traceability between fired primer and the load it came from. They are very inexpensive. Using a hammer, you punch out fired primers one at a time. I can't really help more than that because I've never used AA2230. |
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Posted: 8/9/2018 8:17:23 PM EDT
[#17]
Aw you'll be all right. Some are ridged, some are not.
Stay where your at for now. Pay attention to eject pattern if AR, or sticky cases [bolt action]. I'd shoot the hell out of them based on primer looks, if nothing else shows up. But it's only one thing, if that's the only sign, no head swipes or patterns on the case head from the bolt, then go by how they shoot. |
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Posted: 8/10/2018 9:24:50 AM EDT
[#18]
I am seeing a loose headspace issue not so much flat from high pressure.
Your primer is ejected to the bolt face then the brass comes rearward as pressure builds reseating the primer using the bolt face as a stop. That’s how you’re getting round edge muffin topped spent primers. |
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Posted: 8/10/2018 11:54:20 AM EDT
[#19]
The outer back edge of every one of the primers is still nicely rounded.
It appear that the firing pin hole is a little large and producing some cratering around the pin indent. You can live with it or have it bushed and re-bored. It is not grossly excessive just a little sloppy fit. |
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Posted: 8/11/2018 6:06:09 PM EDT
[#20]
I've looked at those pictures several times, and I still do not see any flattening of the primers you say are flat. I DO see some cratering around the firing pin indentation, but there are a lot of things that can cause that which have nothing (or very little) to do with pressure.
To repeat what others have said, since the edges of the cups on all of the primers you photographed are still very nicely rounded, they are NOT flattened. |
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