How Flat Are These Primers?

TX_Diver

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Awhile ago I did an OCW test across a wide range of charges and eventually settled on the load I have now. Wondering if I didn't miss some pressure signs back then though so looking for another opinion.

When I did the OCW it was pretty cold so I was leaving the ammo inside, then shooting, looking for pressure signs, coming inside and loading up a new magazine, then going back out, shooting, etc. What I missed during that was comparing the appearance of the primers to one that was unfired...

Yesterday I shot a bit and since it was warm (~35) and I wasn't doing load development I took the entire ammo box outside as I normally would. At the end of the day I happened to look at the primers next to some unfired primers and realized that I may have missed some (now fairly obvious) flattening of the primers with the reloads when I was doing my OCW test.

Load is a 77gr SMK in 1x LC 19 brass w/ 24.0gr of N140. The VV app lists 24.7 gr as the max (book = 2657 fps, I got 2772 at 24.6gr). Sierra lists 22.7gr as max (book = 2620 fps, I got 2597 at 22.8gr). These loads at 24.0gr were at 2710 fps when I originally did the OCW test back in November. Rifle is a T3x Lite w/ 22.4" barrel. I am cutting the barrel down to 18" shortly so at that point I'll need to re-evaluate obviously if I lose a bunch of velocity.

From all that I'm interested in opinions on the primer flattening shown below. The left column (single row) was 22gr of N140 with a 75gr ELD-M in LC18 brass. The right 2 rows was 24gr of N140 w/ a 77gr SMK. I'm guessing I should back off a little further to 23.5 gr or so of N140 (I was getting 2642 fps at 23.4gr) but wanted to at least get a second opinion.


5zvIbuJ.jpg


bjmSHuF.jpg


Regarding the other marks on the brass I believe those were there. The last time I shot I took a sharpie and marked the brass anywhere it had an indent, ding, scratch, etc. across 10 round to make sure that they were from the original firing (presumably a semi-auto). I was not getting any new ejector or bolt swipe marks from my gun.
 

DIBBS

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  • Aug 21, 2008
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    Looks to me like you still have rounded edges on the primers and are gtg. (for current conditions)

    However, if you believe you may be at the upper edge for your firearm, and you have the potential to hunt/shoot in wet weather, you should pro do a water test... ie wet the case and insert in chamber and fire.

    You also may want to retest in the hottest temps you will shoot in.
     
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    Near miss

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    Here is my recent charge test, 24gr sounds quite mild for 77.
    20220201_111728.jpg


    Please note that the brass had already the marks, this is why the one 1.67 case is smooth and other not. Only primes were flattened.

    Temp was around -4C / 25F

    It was raining snow when I shot these so small amounts of water was introduced to the rounds,
     

    MarshallDodge

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    This is a flat primer-
    20220207_120341_resize_95.jpg


    It's too bad that I had to turn that load down but it is ball powder on a 40 degree day, and I was worried what would happen on a 80-90 degree day.

    20220123_145647_resize_17.jpg


    The group doubled in size when I dropped down a half grain but hopefully it will come back when the weather warms up.
     

    softcock

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  • Mar 24, 2006
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    You will immediately know you are to HOT with flat Primers . When you can see the Brass flow, and clearly read the word ' LAPUA ' on the Bolts face .
    .
     
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    Steel head

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    If the primer edge still has a radius, it is not as flat as it could be. I've seen military fired rounds that had no radius. That's Hot.

    BugIn
    You will immediately know you are to HOT with flat Primers . When you can see the Brass flow, and clearly read the word ' LAPUA ' on the Bolts face .
    .
    34206516-B9D3-46AD-8611-1972B6BE939F.jpeg
     

    OkieMike

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    This is a flat primer-
    View attachment 7802849

    It's too bad that I had to turn that load down but it is ball powder on a 40 degree day, and I was worried what would happen on a 80-90 degree day.

    View attachment 7802857

    The group doubled in size when I dropped down a half grain but hopefully it will come back when the weather warms up.
    On the bright side... It's only flat on top.

    Mike
     

    TX_Diver

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    Thanks all. I'll pay attention as the temps warm up but will keep rolling for now. May tweak the load after the barrel gets cut anyways.
     

    stefan73

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    If you blow out your primers you just alleviated an extra step in the reloading process:eek:. Follow me for other great reloading tips:ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO:

    Disclaimer: It's just a joke, do NOT reload past safe specifications in reloading manuals.

    And, no those primers are not flat. I was pushing for speed with my .300 WM and running 210grn Bergers to 2975 FPs with a 22" barrel. My brass didn't like it.
     

    roostercogburn98

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    If you blow out your primers you just alleviated an extra step in the reloading process:eek:. Follow me for other great reloading tips:ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO:

    Disclaimer: It's just a joke, do NOT reload past safe specifications in reloading manuals.

    And, no those primers are not flat. I was pushing for speed with my .300 WM and running 210grn Bergers to 2975 FPs with a 22" barrel. My brass didn't like it.
    I blew quite a few 5.7x28 primers out when I was doing load development in my bolt gun!!!
     
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    stefan73

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    I blew quite a few 5.7x28 primers out when I was doing load development in my bolt gun!!!
    The primer pockets on my .300WM brass from my more recent H1000 experimentation couldn't hold a primer after one firing and the velocities I was seeing was nothing extraordinary. Maybe just crappy brass? My RE22 loads beat the tar out of my rifle (primer flow into the firing pin hole), broken bolt knob trying to extract a case, blown primers but dang would it shoot!!!
     
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    roostercogburn98

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    The primer pockets on my .300WM brass from my more recent H1000 experimentation couldn't hold a primer after one firing and the velocities I was seeing was nothing extraordinary. Maybe just crappy brass? My RE22 loads beat the tar out of my rifle (primer flow into the firing pin hole), broken bolt knob trying to extract a case, blown primers but dang would it shoot!!!
    22 Nosler destroyed brass as well. Worthless shit round wasted a lot of my time and components
     
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    softcock

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    If you blow out your primers you just alleviated an extra step in the reloading process:eek:. Follow me for other great reloading tips:ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO:

    Disclaimer: It's just a joke, do NOT reload past safe specifications in reloading manuals.

    And, no those primers are not flat. I was pushing for speed with my .300 WM and running 210grn Bergers to 2975 FPs with a 22" barrel. My brass didn't like it.

    YES ... LOL .. Going to the point of Flat/pierce/gas blow on Primer and a stiff Bolt lift is the 1st BIG warning sign . pushing cartridges to the wall, the gains are not there, and possible damage to your Rifle or Yourself is pretty real .
    ( when young and stupid ) , I have fucked around over the years 'Purposely pushing' to the limit on a few shortaction cartridges with , 'real' FLAT Primers, Gas Blow and Piercing Primers . Also pushing to the point of only getting only ( 1 ) firing to new Brass, because the Pockets were toast and would not hold a new Primer for the 1st reload . . And YES ... LOL , you really can read the case head printing of your brand of 'Lapua' Brass on the face of your Bolt Face with the brass flow .
    . . But , Never had the Balls to really push Longaction Magnums like my 300wm to the wall, Magnums always commanded more respect with bigger powder charges and bigger consequences when your luck bucket is empty, and going past the edge .
    .
     
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    stefan73

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    YES ... LOL .. Going to the point of Flat/pierce/gas blow on Primer and a stiff Bolt lift is the 1st BIG warning sign . pushing cartridges to the wall, the gains are not there, and possible damage to your Rifle or Yourself is pretty real .
    ( when young and stupid ) , I have fucked around over the years 'Purposely pushing' to the limit on a few shortaction cartridges with , 'real' FLAT Primers, Gas Blow and Piercing Primers . Also pushing to the point of only getting only ( 1 ) firing to new Brass, because the Pockets were toast and would not hold a new Primer for the 1st reload . . And YES ... LOL , you really can read the case head printing of your brand of 'Lapua' Brass on the face of your Bolt Face with the brass flow .
    . . But , Never had the Balls to really push Longaction Magnums like my 300wm to the wall, Magnums always commanded more respect with bigger powder charges and bigger consequences when your luck bucket is empty, and going past the edge .
    .
    I call it my "self destructive" behavior which fits. I found that node by working up and it just grouped (the RE22 load) like nothing else. I have a lot of ideas on what I would like to do for my next .300WM all of which are get a solid shooting .300WM while not trying to destroy a rifle.
     

    TX_Diver

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    Loaded and shot some at 23.5gr today out of curiosity and primers look extremely similar to the 24.0 gr (maybe slightly more rounded).

    40 degrees out.
    24.0gr on top then 23.5 below
    2uI80Em.jpg


    TvVHZ23.jpg


    Got 2648 avg over 5 shots so may just keep rolling with 23.5 for now til I get the barrel cut then re-evaluate.
     

    zeroz

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    OP, all looks peachy in pressure land. When you stop seeing that recess around the primer, then you have FLAT.

    Sounds like you need a 300 RUM Stefan. Pushing magnums like that is spooky
     
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    three horsemen

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    Great thread. I always think about at what point do I stop adding more powder in search of the perfect load. I have mostly powders for the 30-06 and 6.5 creedmoor and load data is scarce for a lot of the different bullets I use for the 556. It is all about the radius when looking at the primer. I try to pick the lower node that offers the best accuracy. But if your shooting long range that might not be an option. So this thread really put my mind at ease, thanks.