Your opinion of what is the closest substitute for Rem 7 1/2 primer

Discussion in 'Reloading Forum (All Calibers)' started by VaniB, Sep 29, 2019.

  1. VaniB

    VaniB

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    Yes, I'm trying to stick with the Rem primers, being that's what my test loads are based on. The problem is with both brand new brass, as well as fired brass. I guess spending a LOT of time per case drilling the uniformer into the pocket helps. I have to drill long and hard enough so that the backstop plate of the uniformer is scraping the Lapua name on the brass. Only then does the pocket seem to be deep enough. Thanks.
     
  2. VaniB

    VaniB

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    I measured the Rem primers in 3 different cartons I have on hand (and 3 different lots bought months apart) all to be .122" tall. (And that was using both a digital, and a manual caliper..... so the problem is not faulty caliper readings.)
    I don't know where the specs you found are coming from, but they are certainly at odds with my actual measurements I'm getting. Perhaps with the anvil removed they might measure. 110"

    Thanks for the links of the uniformers. The simple Lyman and RCBS uniformers I have, (which screw into the green handle) aren't fancy but they do their job and work.
     
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  3. Uncle Ed

    Uncle Ed

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  4. RegionRat

    RegionRat

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    VaniB, sometime when a cutting tool is designed, the volume space for removed material is smaller than we would like. The cut material can “clog” the cutting action and cause a number of finishing issues. With cartridge brass, it is easy to miss the difference.

    See if the reason your pocket uniforming tool seems to be giving you a struggle has something to do with an unusually high amount of material it needs to remove causing the need to clear the chips several times to achieve the final cut. When you think you are done, clear it and run again over a mirror or clean surface to see if more material is still being removed.

    I have seen this happen over a lifetime of different batches. My usual case prep run with one of the carbide tools didn’t finish after the first pass on some statistical samples. I ended up going back over those batches and was surprised to find the cutter was still removing significant amounts of material on some samples. It hasn’t happened often on Lapua, but it has still happened often enough that I watch for it on every new batch.
     
  5. foxguy

    foxguy Gold $$ Contributor

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    Sorry Vanni,

    I took it from some spec's I found online as I don't have any Remington 7 1/2's.

    [​IMG]

    It appears it's to the bottom of the Cup.

    How deep is your primer pocket unformers cutting the pockets?
     
  6. VaniB

    VaniB

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    Foxguy, I just measured the primer cup WITHOUT THE ANVIL, and sure enough it measures the .110" that you indicated from your source. But the primer is a full .122" tall with the anvil included. All my small rifle primers I've seen have an anvil protruding beyond the cup which increases the height. (At least all the different primers I own, do) A primer is not sold without the anvil and does not function without the anvil, so what good is it for that that source to have provided a measurement without the anvil and NOT at least reference and/or mention the anvil? No need for you to say your sorry to me, as it's not your fault that the source is incomplete & confusing. We get this same sought of thing with what we hear between Fox & CNN News sources and often have to come to our own conclusions what may or may not be half truths. (not that I give CNN 5 seconds of viewing day) LOL. I appreciate you taking the time.


    RegionR, Yep, just a fact of natural physics that micro cutting blades can jam up and often need to be cleared. I might need to spend 1 hour uniforming the primer pockets on a NEW box of 100 Lapua 221 brass cases. But, it will only need to be done once, so I only cry once. LOL. But, I suppose if I didn't want to spend an hour doing that then I would NOT be a handloader and I would take up some other hobby like butterfly collecting, etc. It can often take me an hour just to load up 5 cartridges. Then I will spend 2-3 hours at the range firing off the 25 rounds I spent half the day making. Gotta love this hobby.... Keeps one away longer from an angry wife.
     
  7. Doom

    Doom

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    See attached. Height dimension is to anvil.
     

    Attached Files:

    Last edited: Oct 2, 2019
  8. VaniB

    VaniB

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    Thanks guys for the input. But now we're beating a dead horse here with statistics that don't change anything. It doesn't matter what size or dimension the primer is called, what matters is that it doesn't fit my brass case and what course of action I choose to take to remedy that.

    Appreciate the links and info. Thanks again.
     
  9. Doom

    Doom

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    Not trying to beat that horse, just wanted to post the SAAMI pocket dimension. I’m not real familiar with the Rock Chucker but could the issue be with the shell holder?
     

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