Auto 5 Magnum 12 with light loads

Discussion in 'Shooting - Reloading Forum' started by Sunklands, Apr 10, 2018.

  1. Sunklands

    Sunklands Elite Refuge Member

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    I picked up a case of Estate 1 1/8oz, #6's, that are 1300fps, at a store close out a couple weeks ago. I shot a box of them with my Belgian mag 12 and they cycled and shot well. When I switch to using my "new to me" jap mag 12, it would cycle them about 75% of the time. I took the Jap gun all the way down after I got it and examined it. The friction rings are all good, mag tube is very clean, recoil spring is good, and I replaced the action spring. Comparing the two guns, the Belgian has the double recoil spring, whereas the Jap has the single. Seems to me that it should cycle the 1 1/8oz ammo but, there's an obvious difference between the guns. Or is this brand of ammo just borderline for functioning in these set ups?
     
  2. teul2

    teul2 Senior Refuge Member

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    post a pic of the recoil spring with the friction rings as they are setup on the Jap mag 12. I am curious.
     
  3. Sunklands

    Sunklands Elite Refuge Member

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    I'll have to post a pic later but, it's set up with 1 friction ring and 1 bushing on top of the recoil spring.
     
  4. Steelshot Scott

    Steelshot Scott Senior Refuge Member

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    My Jap-made A5 will only cycle reliably with heavy dove loads. You need to replace the recoil spring with a recoil spring for a A5 Light 12. Do not forget to switch it back before firing magnum loads.I have found that lubing the top of the barrel where it contacts the receiver also helps this problem.
     
  5. Sunklands

    Sunklands Elite Refuge Member

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    Thanks Scott. I'm assuming they(Miroku) used a heavy spring because of the heavier barrels? What if I replace the jap single spring, with a Belgian double spring?
     
  6. A5Mag12

    A5Mag12 Elite Refuge Member

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    Your Belgian gun is just worn more. Neither was designed to shoot 1 1/8 oz lead loads. High power/high brass 1 1/4 oz lead loads were the smallest recommended loads for the Mag 12.
     
  7. buck_master_2001

    buck_master_2001 Elite Refuge Member

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    My Jap will not shoot light loads reliably either. Never has.

    Sounds like the trick is to swap out the recoil spring??
     
  8. Sunklands

    Sunklands Elite Refuge Member

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    Thanks boys, I may find me a standard 12 or light 12 recoil spring for it. Ah hell, I've been looking at a nice Remington 11 that's cheap, surely the wife will be on board. Maybe the spring in that 11 will work in that Mag 12.
     
  9. buck_master_2001

    buck_master_2001 Elite Refuge Member

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    So what about 1 1/8 oz steel loads? Would the light 12 spring be better to shoot those out of a mag 12.
     
  10. 10GAGENUT

    10GAGENUT Elite Refuge Member Sponsor Flyway Manager

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    I'll make you some 1 1/8 oz leads loads that will cycle in it, off the shelf ain't gonna cut it.
     

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