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Thread: Loose primer pockets?

  1. #1
    Member Alangaq's Avatar
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    Default Loose primer pockets?

    In regards to brass and primer pockets in particular; just how loose is too loose? I am aware that loose fitting primers is a sign of brass that has been exposed to excessive pressure, but the term “loose” is so vague and subjective as to be nearly useless. Case in point; I have been working up loads for 375 Winchester in two different rifles, a BB94 and a Marlin 375 using cast bullets described in previous posts on this forum. I have started off with 100 pieces of brass (Winchester) and will use these exclusively for load development and will then trash the whole lot, or segregate them for plinking loads. That said, I have not been particularly careful about keeping track of how many times they (individually) have been loaded, but some are now on their 4th or 5th go-round; The mechanical force required, using an RCBS hand priming tool on some of this brass is now nearly effortless. It is not to the point that the primers are actually loose in the primer pocket, or in any danger of falling out of the brass, but the physical effort required to seat them into the case is noticeably less than with new brass……………I think. But again, this is going on “feel” and no two cases seem to be exactly the same. I am also wondering if perhaps this is just typical for Winchester brand brass, as I seem to notice similar characteristics with the 30/30 and 30-06 Winchester brass, and not so much with Remington brand.
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    Default Loose Primer Pockets.

    A couple of my thoughts: I appoligize if I don't answer your question.

    I don't use my press anymore for priming brass. I don't have near the feel with the press as I do with a hand priming tool such as a Lee Priming tool. I've had some hot loads that when repriming it felt as though there wasn't any resistance at all when pushing home the primer. Those cases were tossed, or saved for plinking, and I reviewed my range notes to ID the load in question.

    I think there is a difference in brass as to it's resistance to stretching in the primer pocket area. I see the most stretch in Remington and Winchester brass, less with Federal and Norma, and Lapua being the most resistant to stretching.

    Certain primers do fit tighter than others, either because of the material used or actual diameter of the primer. I'm not sure which one it is either, one of these days I'll spend some time and figure it out. CCI seem to be the tightest of the brands I use (Winchester, Federal, and CCI). For practice (plinking) loads I've substituted CCI for Winchester or Federal primers to take up some of the sloppyness of the primer pocket.

    Woody

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    To me, ‘Too Loose” means very loose, not the normal variation of how easily some go in compared to others. That could be due to how well the primer is lined up with the pocket when you push it in.

    The argument for using a Hand primer seater as opposed to the primer arm on a bench press, is that you can “Feel” them better, and I suppose that may have some merit, if you could “Feel” the difference.

    When I did that, I threw some brass away, but since I’ve used only the primer arm types of primer seaters, I haven’t thrown away any brass because I thought primer pockets were too loose, and I’ve experienced no problems. I like the extry leverage.

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    I not you did say you use an RCBS hand priming tool and I assume you have used it throughout. You would be able to say then that pockets are now "looser". (is that a word?)

    I can't say how bad they are and you'll be the judge, When I gind loose pockets I toos them aside and segregate in a zip bag to make that the last loading.

    The 375 Win does not operate at pressures that would normally stretch primer pockets. After a number of loads they will stretch however. Some brands certainly do open primer pockets more easily than others and Winchester seems to do it more. That is one of the reason I like useing Winchester brass, it serves as a limit on my loads. It is good brass otherwise. The head (rim area) of the case should be hard and the mouth soft annealed on any caliber. I think Winchester is a little softer at the rim area than some. You could also just have a soft batch. I'd toss these soft seat primer cases after this firing. You might consider another brand of primers as cup diameter may vary some and softer cups, like federal, will seat tighter in stretched pockets..
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  5. #5

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    I can't remember ever having any issues with primer pockets stretching at the operating pressures that Marlin an Winchester lever guns operate at. Most of the lever gun brass that I've pitched were done so because of split cases not stretched primer pockets.

    Have you had this happen before with the 375? My first thought is a bad lot of brass!

  6. #6

    Default loose primer pockets

    Normally, an oversized primer pocket is not caused by pushing primers into them too often, and primers of different hardness or consistency in their roundness can make it seem like the pocket is wrong. Oversized primer pockets are generally caused by too much pressure. That being said, they are only one sign of excessive pressures among a number of other ones. Are the primers themselves overly flat and enlarged looking after firing, with a cratered firing pin strike. Is the lettering on the base of the case smeared and shiny. The most important sign of excess pressure is over-expansion just above the case webbing, though theories vary as too how much is too much. Signs of incipient case head separation, another sign of excess pressure can be seen as a vague ring on the outside of the case just above where the inner solid section of the base ends which can easily be checked out by taking a thin hard piece of wire, bend a short piece on the end and sharpen the end of it. Running it up and down inside the case will allow you to detect a beginning separation. Then too, bad manufacturing procedures can create inconsistent primer pocket diameters
    I know, this thread started out just talking about over-sized primer pockets. The only over-sized pockets I have personally experienced occurred quite quickly once a certain excess pressure was reached. I have never, to my knowledge, had one occur using normal pressure loads. But, I don't use any kind of device as a primer pocket cleaner that removes any material when cleaning the pocket.
    I check pressure signs on the case after every shooting, but i don't just toss the case without a good reason, especially with what brass costs these days. I have sometimes annealed necks and shoulders after the brass becomes work hardened, but as long as the case looks good without signs of case failure, I keep using them. I have had cases that I didn't max loads out in that I've used twenty times or more, but i check them very carefully.

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    Default

    Thanks for the valuable input guys. I managed to find a couple of first run, un-fired cases and the “feel” inserting the primers is similar to all the other cases that have been fired multiple times. I now suspect that when I changed from CCI to WLR primers after the third go-round on working up loads that, that is when I noticed the reduced effort in seating the primers. After reading your comments and re-analyzing my load data, I am now confident that none of the cases have been subjected to excessive pressures. I am a bit embarrassed that I did not “connect the dots” so to speak and realize it was the primer brand change that was causing the reduction in seating effort, but I guess I just leaped to the conclusion that I was getting some case stretch in the primer pocket due to over pressure. The 375 Winchester is a rather high pressure loading for a lever gun (hence the Big Bore receiver modification) but none of my loads has exhibited any other signs of excessive pressure, but I do believe them to be close to maximum for this chambering as I am routinely getting 1900 fps + with a 265 grain cast bullet from both rifles.

    As a side note, if any of you were curious as to the Marlin Micro Groove barrel versus the Winchester tube, I can report that both work very well with cast bullets (gas check) and the Winchester, in the case of my two rifles at least, leads the Marlin by about 50 fps in every load, and also groups about ˝” better with every load at 50 yards. I wouldn’t go so far as to say that this would hold true for other rifles out there by these two manufactures, but I did find it interesting with these two particular guns.

    Thanks again for your input and advice…………..rest assured that it has been duly noted!
    “You’ve gotten soft. You’re like one of those police dogs who’s released in to the wild and gets eaten by a deer or something.” Bill McNeal of News Radio

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    I have noticed that different primers even from the same brand (I've only used Fed 210M so far) vary in diameter. At first, I thought my new Starline brass (flash hole deburred, primer pocket uniformed) varied and I blamed my 'new hands' and the primer pocket uniforming. While putting primers into the cases with the RCBS hand tool, I found that the pressure required varied. I got one primer that would NOT go in, period ...tried another and it went in just fine. A few cases later, I had one go in that felt like it went in pretty easily ...so I experimented. I ran the case carefully into the sizing/depriming die to push this primer out, then I pressed another primer into it. Voila! The second one that I put in went in with a lot more resistance. I came away from the whole experience believing that the primers varied more than the brass did...

    Brian

  9. #9

    Default CCI primers

    I started using CCI primers again after many years of not using them. They may be more consistent roundnesswise (is that a word?) then they used to be, but in years past, they would do terrible things in a progressive press. The hard out of round cups would actually shave little bits off the edge of the primer pocket. These shavings would start making indentations on the installed primers in their little half moon shape. It remains to the imagination what might happen if you worked things a little hard and fast with the shaving in the wrong place. They also started building up in tightly fitted places in the press, finally jamming things up and demanding a tear-down. That is when I started using Winchester primers exclusively. They were very consistent and softer so that pressure signs would show a little sooner and more clearly. Never had a problem with them.

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