Pressure Signs .223

Discussion in 'Reloading' started by brettm357, Jun 6, 2012.

  1. brettm357

    brettm357 New Member

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    Apr 26, 2012
    Have some cratering using 25.6gr Benchmark with Nosler 55gr Ballistic Tip with Remington SPS 700 - Very Accurate load - 2 on left of pictures are Reloads 2 on Right are Factory - Does the Cratering Look Severe
     

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  2. J E Custom

    J E Custom Well-Known Member

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    It looks like the problem is that the firing pin hole in the bolt is two big (Two much clearance
    between the firing pin and the firing pin hole in the bolt).

    Have a smith look at it and see if it needs to be fitted with an over sized firing pin.

    It should not do that with factory loads and with hot loads could cause primer failure (Blown
    primers).

    Having a bushing installed will also fix this condition, but may cost more than a replacement
    firing pin.

    J E CUSTOM
     

  3. RTK

    RTK Well-Known Member

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    J E is spot on, I can flatten primers pretty well and never have anything close to that in cratering and you are not flattening them at all
     
  4. SidecarFlip

    SidecarFlip Well-Known Member

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    Plus 3. Thats not a hot load. I reload hundreds of 223's. I prefer the Hornady FMJBT's in 55 grain with H335 or 322, depending on my mood.

    That is surely a component/action issue.

    You need to be watching your case mouth's as well. I've taken to annealing mine regularly.
     
  5. K31Scout

    K31Scout New Member

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    Jun 3, 2012
    I love BM for the 55gr but Varget is "almost" as good and never shows pressure signs. I have to be careful with BM because MAX creeps up fast and below what Hodgdon shows in their manuals for my Howa 1500 bolt and RRA AR15.
     
  6. johninok

    johninok Well-Known Member

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    weak firing pin spring/ firing pin hole issue. had a couple like that, a quick trip to Greg Tannel took care of it. Cratering in pics is normal.
     
  7. Bart B

    Bart B Well-Known Member

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    Looks just like my .264 Win. Mag. I had built on a Win. 70 action. The hole in the bolt face was way too big. A 'smith did a hard chrome plating job on the last 3/8ths inch of the firing pin then ground it down to about 2/1000ths smaller than the hole's diameter.

    I've seen large rifle primers with very rounded edges indicating a mild load actually have higher peak pressures than SAAMI specs. Such is life with hard, thick primer cups. Soft, thin cups will show their edge sharp at very low pressures. All of which makes it hard to generalize that primer shape after firing is a good indicator of pressure.
     
  8. Mikecr

    Mikecr Well-Known Member

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    Primers cannot be used as a single pressure indicator.
    Unless piercing or falling out, I wouldn't even pay them any mind.
     
  9. Bart B

    Bart B Well-Known Member

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    In looking closer at those dimples in the primers, they're quite shallow. I think you should have your firing pin spring replaced or get a longer one. Measuring the strength of the springt you have then comparing that with specs will tell if its weakened too much. If the firing pin doesn't protrude at least .050" (or about .005" more than half the firing pin tip diameter) from the bolt face when it's full forward in the bolt, it's too short; they should protrude at least that much and .055" is better.