Primer blowby - 9 mm handloads

Discussion in 'Handloading and Reloading' started by Stefano189, Sep 28, 2015.

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  1. 1SOW

    1SOW Member

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    I've never bought a 9mm case. Somewhere around 80,000 - 90 thousand loads. 60K were in one pistol I still use as a back-up gun. I reuse the cases until the primer hole 'feels' loose or the case starts to split at the case mouth.
    Win, WCC Nato, R&P, PPU and some F.C. & Speer (both ATK and load similarly) are the cases I use. Win is my preferred brass followed by R&P. The FC and Speer are noticeably 'softer' when seating bullets and primers. Other ATK brass I don't use is waay softer yet.
    Pick up all the range brass you can every time you can. After you have 10-20 thousand cases, you won't wear out the brass for a very long time if you go through ALL the cases sequentially. Or not. JMO
     
  2. beag_nut

    beag_nut Member

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    For what it's worth:
    I never use a tumbler for case cleaning. I use an ultrasonic cleaner and Hornady cleaning solution (at their recommended ratio). I have never had what you describe, after more than 4000 handloads, spread over 300 cases.
     
  3. Stefano189

    Stefano189 Member

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    Ironworkerwill: I did remove a half dozen or more primers from the affected brass and they didn’t look much different than those from the cases that did not show any blow-by. However, I am not positive that I am not missing something. I’ve now fired all the cartridges with the old brass and the next step in the process is to shoot some factory ammo and reload those cases, shoot them and then look at the primers very carefully after each session at the range.

    Gamestalker: Actually the etching is along the outside edge of the primer and there is still plenty of material or so it appears to support the primer. While I would like to replace the slide, the price is steep and the Sig rep gave no indication or warning about an imminent failure or warning regarding safety. As mentioned in a previous reply Sig is supposed to be making available slides that accept red-dots (rail on the slide) and if they become available relatively soon I will spring for one of those.

    Njl: I was not really aware of the etching until I was told by Sig when the gun was there for a recoil spring replacement. However, the gun was also there for a rear sight replacement about a year ago (9/24/14) and the slide was inspected and apparently it was fine at that time. The gun is 4 years old and it was about a year ago that I started reloading. I didn’t use the 5.3 gr. load very long because the charge was insufficient and caused a couple of failures to eject so I increased the load to 5.5 grains which solved the problem.

    I am de-capping the brass first. I guess there is still the question of whether the SS pins are in fact enlarging the primer pocket over time or if the brass is at fault or a combination of both. I’m going to fire some factory ammo and reload those cases and see where it takes me. I will look at the primers after firing the re-loads now that I’m aware of the problem.

    1SOW: I’m relatively new to reloading and I’m trying to learn what “loose” is regarding primer insertion resistance. My data shows the following percentage of blow-by for cases, by manufacturer, reloaded between 11 and 14 times. Speer 68%, Federal 57%, Blazer 54%, Winchester 20% and Magtech 14%. Federal had the largest number of cases at 102, Blazer was second at 72, Magtech at 51, Speer and Winchester at 25 each.

    Beag nut: I think the jury is still out on the SS pin media and at this point it’s not clear to me how to allocate cause and effect. In your case, using an ultrasonic machine removes the solid media variable. There are some responders who seem to believe that the brass has reached end of life after 12 reloads or so and others who seem to have experience that allows many more reloads which makes me think that maybe the gun itself is a factor. At this point I will have to look at the cases very carefully after each session at the range. Which case manufacturer are you using for your reloads?
     
  4. beag_nut

    beag_nut Member

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    Case maker? Winchester, Starline, Rem, Blazer, etc. Twelve reloads is WAY too short a lifespan for what I do. Even after 20 reloads I get maybe one failed case per 400. That includes mostly splitting case mouths, not primer pockets. I definitely put the attention to the tumbler.
     
  5. Rule3

    Rule3 Member

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    All speculation on my part.

    So essentially (regardless of the actually percentages, EVERY head stamp brand of brass has blow by. That is just not right! Even if you did not seat the primers deep enough you should have had mis fires?? Then a second stile would usally seat it and ignite the primer.

    Have you or did you do any thing to the pockets like uniform them or ream them??

    How long do you run the wet tumbler when cleaning, Unless you are leaving it on overnight and grinding the brass to death I do not know how that can mess up the the pockets but clearly it has happened to all brands,

    Of course Sig will not admit or warranty a gun when they know reloads have been shoot though it, Hate to see this on such a nice pistol.

    Only thing I can suggest is load some new brass or once fired brass (by you) and see if there is the same condition, if so there is a problem with the gun (what I do not know)
     
  6. 1SOW

    1SOW Member

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    I agree with Rule3.
    Yours is a unique problem in my and reloader friends' experiences.
    I reload 9mm on a LEE turret press. Like a single stage, this gives a "feel" for each reloading step.
    I also sort by headstamp and only use Federal SPPs, so handle pull pressure is fairly consistent. I seat each primer just as deep as it will go into the case. They are easily seen to be below the base. Eventually, some case primer holes require noticeably less pull to seat the primer.

    No evidence of any significant pressure/heat release in four different 9mm pistols (counting my son's pistol.)--ever.
    All pistols leak some amount of pressure back around the case until it better forms/seals to the chamber. None should show the etching you showed in the pictures.
     
  7. joem1945

    joem1945 Member

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    Have you checked your scale with check weight to verify your powder charge? The only time I had blowback like that was shooting Israeli 9mm sub gun ammo and that stuff was really hot.
     
  8. Stefano189

    Stefano189 Member

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    Rule3: I did absolutely nothing with the primer pockets. No reaming or making them uniform. I take the fired cartridge, decap and resize and then put the cases in the tumbler and tumble for about 2 hours, rinse, let dry, usually overnight and insert primers with a Hornady hand priming tool. I seat the primers as far as the tool allows without putting excessive pressure on the tool. Currently the primers are CCI 500s and depending upon the brass, some seem to insert easier than others but I look at all of them and the primers are at least flush with the case or slightly under-flush. I will start with new ammo this week and post the results.

    joem1945: When I started reloading I checked the powder weight against an electronic scale that came with the Hornady Classic set up and the weight was identical. I use a RCBS balance scale and always zero it before I start measuring any powder. I was also concerned about the accuracy of the scale so I kept track of the number of reloads when I was using CFE Pistol (5.5 grains/load) and my records indicated that I reloaded 2525 cartridges with 2 lbs. (14,000 grains) of CFE Pistol for an average load of 5.544 grains per load.
     
  9. Dudedog
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    Dudedog Contributing Member

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    After that many reloads I would say the brass is just worn out. Most of mine becomes scrap because of #1 loose primer pockets, #2 case neck splits, and sometime #3 case neck tension.
    If you are loading them a bunch one issue to watch for is the brass becoming overworked and failing to hold neck tension correctly.
    This can result in bullets being shoved back into the case resulting in increased pressure. When they get really bad you can push the bullet deeper with your thumb.
    Cases like this are an accident waiting to happen.
    There comes a time when all cases are good for is scrap.
     
    Last edited: Oct 7, 2015
  10. RussellC

    RussellC Member

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    As an aside to all this, much of the brass (9mm) I have that has loose primer pockets with Winchester SPP, is cured by using CCI SSP primers. Using them, I rarely have a loose fit. Same with Tula, but I seem to get failures (duds) more often with them. I assume they are slightly larger? Never put a micrometer to them.

    If your primers are loose with CCI, the pocket is likely shot. Just my opinion. I also wet tumble with steel pins and havent noticed any premature wear with 9mm, .45 ACP, or .223 brass concerning primer pockets.

    Russellc
     
  11. Stefano189

    Stefano189 Member

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    Dudedog: Thanks for your input. I reload only 9 mm and it's encouraging to hear that you have experienced loose primer pockets as it lends credence to the problem I've been experiencing. I'm starting with new factory ammo and will reload those cases and look very carefully at the primers after each session at the range. I will post the results on a timely basis.

    Russellc: I use CCI 500s (Small Pistol Primers) almost exclusively and have never had one misfire. I did measure a few of them with a good caliper and they were in spec. 0.1745 - 0.1765. You are the first responder in this thread that uses SS pin media to clean brass. I find that it works very well but several responders including a friend have reservations because of the hardness of the SS pins. Since these pins work in a fluid medium one would think that they would have a minimal to zero effect on the primer pocket but there appears to be no data to support that conclusion. Unfortunately it's a long process to determine the effect, if any, of using this media. It would be beneficial to hear from others who use SS pin media and read about their experiences. It seems each manufacturer has a slightly different brass alloy, some harder than others which could explain why some primer pockets fail before others. Do primer pockets become larger not only because of inserting new primers but also because of the firing of a cartridge - expansion in addition to wear?
     
  12. Walkalong

    Walkalong Moderator Staff Member

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    Assuming no process is enlarging the primer pockets, then either you are running loads that are too hot and pressure is enlarging the case head, the primer pockets along with them, or these cases have been fired a lot. How many times at safe pressures it would take I don't know, because I haven't had that problem.
     
  13. vaalpens

    vaalpens Member

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    Interesting point. Have you tried debulging your brass? When debulging and you feel a lot of resistance, then maybe Walkalong is correct in his assessment.
     
  14. Stefano189

    Stefano189 Member

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    Walkalong & vaalpens: I've started anew with 150 rounds of factory ammo (115 gr, FMJ); 50 rounds Blazer, 50 rounds Fiocchi, 50 rounds Magtech. I fired this lot (no problems with primer blowby) and have cleaned the brass as follows:cleaned Blazer with barley (recommendation from a friend) for about 4 hours; cleaned the other two with the SS pins for about an hour and half. My friend and I inspected the cases after the cleaning and could find no differences to speak of between the cleaning methods (also used a 5X loop).

    All the cases were resized before the cleaning process and with the exception of one or two "sticky" cases, the only comment I can make is that the Magtech cases seemed to require a little more effort to resize. Remember this is now once fired factory ammo.

    All the cases were subsequently primed with CCI 500 primers. One thing I noticed is that the Hornady hand priming tool I use seats the primers just below flush with the bottom of the case and it seems to depend upon the radius of the primer pocket since the diameter of the tool that inserts the primer measures 0.186 and the primer pocket spec is 0.1730 - 0.1745 for a difference of ~ 0.01". Just an observation.

    I will reload with 5.8 grains of Alliant Power Pistol and 115 gr JHP Montana Gold bullets with a COL of 1.090. This is a slight modification of the recipe in the Hornady Manual since the Montana bullet is ~ 0.015" longer than the Hornady XTP JHP used in the recipe.

    I will continue to post results as they become available.
     
  15. larryh1108

    larryh1108 Member

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    There's a lot of excellent minds here but not a lot of mention of (possible) bullet setback from chambering a round. If the brass has been resized 10+ times and the neck tension has loosened a bit it may be possible that the neck tension is failing. I'd run a mag thru the chambering process and then ejecting the round (without firing it) and remeasure the OAL to see if there's enough setback to cause overpressure. It's worth the 2 minutes to check.
     
  16. Walkalong

    Walkalong Moderator Staff Member

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    Excellent idea.
     
  17. Stefano189

    Stefano189 Member

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    larryh1108: Thanks for the suggestion. It happens that I have 5 rounds left from the group of cartridges under discussion. Thursday I will take them to the range (with my calipers) and do as you suggest. I will post the results after I run them through the gun.
     
  18. Stefano189

    Stefano189 Member

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    larryh1108: I measured the 5 rounds that I had left over from the subject batch and I measured the COL of each with a range from 1.0771 to 1.079) and loaded them into a magazine. I racked the slide which loaded the first and proceeded to re-rack (eject) each of the 5 cartridges in turn. I measured each cartridge again and there was no change in the COL of any cartridge.

    I also fired 150, one-time reloaded brass today, with absolutely no sign of primer blowby. I will continue to reload these 150 brass cases and carefully observe the primers. The brass consisted of 50 Blazer, 50 Magtech and 50 Fiocchi. Results will be posted as they become available.
     
  19. Blue68f100

    Blue68f100 Member

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    I had some LP primers fail in 45acp a couple of years ago. The failure was mainly to RP brass with some Federal. The primers were replaced by the MFG and the MFG paid for the repair to my new BE 1911 gun. I thought it was odd that only 2 mfg had the problem. Further investigation reveled the difference in the primer pockets. These had a relief cut kind of like a ring crimp was machined out vs swedge. These had in excess of 0.010" larger dia (than spec) and 0.020" deep shoulder was removed. This was enough to cause the primers to fail due to the fact they were unsupported in a high stress area. The primers were expanding trying to fill the void. The failure would even happening on reduced BE loads. The strange thing was that not all failed with the same conditions. So apparently these were on the very extreme edge. All the failure were with 200gr LSWC. The some load with 185gr did not have any failures. Ever since I sort by mfg and inspect for this condition on the primer pockets. You would be surprised as to how many exhibit these conditions. Almost looks like the mfg was having a problem with the mfg process. RP with their large radius do make it easier to seat primers but at a cost. Then since this was range brass (most from a friend) some of them may have been altered by some one cleaning the primer pocket with the wrong tool and enlarged them.
     
  20. gamestalker

    gamestalker member

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    Larryh1108, good mention, set back could certainly account for excessive pressure spikes, which could in turn cause hot gases to leak.

    Something else I thought about, and can easily happen to a novice reloader, is over crimping. This could cause a neck tension problem, thus creating set back issues, say 33% of the time.

    Another possible issue related to over crimping, is that, considering 9mm head spaces on the mouth, if it's over crimped, the mouth can actually get constricted during firing pin strike. An over tapered mouth can slip past the head space stop, or what ever that feature is termed as. This is a problem I truly feel is often over looked, thus rarely identified when trying to diagnose a suspected, or possible over pressure situation. This is exactly why I don't like to use the term "crimp" when referring to rimless AL-ing cartridges, as we aren't really supposed to crimp them at all, but rather, just remove any bell that was utilized during bullet seating.

    GS
     
  21. jerkface11

    jerkface11 Member

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    Do you still have primers from that lot that haven't been fired? If so measure one maybe you somehow got an undersized batch.
     
  22. Hondo 60
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    Hondo 60 Member

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    That was my thought as I read the OP
     
  23. amlevin

    amlevin Member

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    To the OP====

    Buy yourself a Primer Pocket "Go-No Go" tool.

    Sinclair has them.

    http://www.sinclairintl.com/reloading-equipment/measuring-tools/case-gauges-headspace-tools/swage-gage-primer-pocket-gauge-prod71030.aspx


    $12 plus shipping.

    If one end goes in and the other doesn't go ahead and reload the case.

    If both go in, toss it.

    Your problem is definitely not firearm, but brass (Unless you are grossly overloading and that usually results in pieces coming off brass or firearm).
     
  24. SCC

    SCC Member

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    Nearly all of the loose 9mm primer pockets I see are in Speer, Blazer, and Federal brass. I see two of the above in your first picture.

    My procedure loading on a Dillon 650 is that if a primer feels "soft" going in compared to the others, I will pull the case from the priming station and set it aside. (I use only CCI primers.) After the main run is complete I load the pulled cases, mark them, and keep those rounds separate. Those cases will be destroyed after firing. This should catch oversize pockets before they become loose enough to become a problem. 9mm brass is just too plentiful to do otherwise.
     
  25. Stefano189

    Stefano189 Member

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    Thanks to all for your comments and suggestions.

    gamestalker: Very early on I identified that I may have been over-crimping. I follow the RCBS instructions very carefully to assure that I don't over-crimp. I try to achieve a taper crimp of .001" - .002"; I measure at a point on the case near the base of the bullet and then measure right at the mouth of the case where the measurement should be .001 - .002" less than the previous measurement. I've also measured factory loads and they are in the range of 0.374" to 0.376" at the mouth of the case which is in line with my handloads for 0.355" bullets.

    jerkface11: I've measured some of the CCI 500 primers and they all appear to be within specification.

    Hondo 60: I'm coming to that conclusion also and I'm watching each reload as I fire them at the range. The first 150 rounds with once-reloaded brass were without blowby.

    amlevin: Good suggestion. I'm looking at the gauge and will probably spring for one.

    SCC: 50 of the brass cases I'm reloading now are Blazer and I'm going to see how they do compared to Fiocchi and Magtech brass.
     
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