450 Ackley build using a Zastava

Discussion in 'Gunsmithing' started by Quaticman, Mar 6, 2018.

  1. Quaticman

    Quaticman AH Member

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    Can I use a Zastava Commercial M70 rifle currently chambered in .458 Winchester magnum for this build? Is it as simple as using a .450 Ackley reamer to re-chamber or am I missing something? What about the feed ramps, magazine lips, etc? That’s assuming that this action can accommodate the extra length of the .450 Ackley cartridge.
    For those of you with more experience I’d love to hear your feedback.
     

  2. CTDolan

    CTDolan AH Elite

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    It's been used for the 375 H&H, so yes, you can (if you know what you're doing...lots more than reaming and feeding involved). Go with the 458 Lott, though. It is every bit as good and a whole lot more common.
     

  3. John P.

    John P. AH Senior Member

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    You will have to open up the magazine well for the 450 Ackley. To the front as most do (Horrors!!!)

    I have a Mark X in 458 Win, a factory built rifle. I am leaving it as is.

    I will also be building a 450 Ackley in the near future. I have the barrel, the chamber reamers, dies, brass, and a BBK Action. The BBK is a big action and will hold 5 down. A bit rough as shown in the photo below, but the long winter hours will take care of the metal finish.

    [​IMG]
     

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  4. CTDolan

    CTDolan AH Elite

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    The action will clean up nice, no doubt. I am curious, though, why not go with the 458 Lott? It's far more common, can shoot 458 Win Mag in a pinch (which you already have, so ammo will have two rifles in which it can be used), and is a ballistic twin to the Ackley.
     

  5. John P.

    John P. AH Senior Member

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    I have two 458 Lott rifles already! I like the nostalgia of the Ackley. I met Parker Ackley years ago and I have always had a respect for his accomplishments.
     
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  6. fourfive8

    fourfive8 AH Enthusiast

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    I think any of the more or less 375HH-based cartridges can be housed in a standard length Mauser, and not sure there is much difference in any of them- 458 Lott, 450 Watts, 450 Ackley (or even the 458 Express in some actions). I know a 458 Win Mag can be fired in a 458 Lott. And a Win Mag and Lott can be fired in a Watts. And a Win Mag, Lott and Watts can be fired in an Express. But, the expanded shoulder of the Ackley prevents similar flexibility with other slightly shorter cartridges. Another seldom reported downside to the longer case length in regular length actions is the availability of bullets with the crimp groove in the proper place. Seems bullet manufactures have designed many of their 458 bullets with the location of the crimp grooves for the shorter OAL of the 458 Mag- grrr :( That seems especially true for some of the 500 grain bullets where the groove is placed well to the rear because of the limited Win Mag case capacity. Just too much bullet nose length added to the standard case length of 2.8- 2.9 of the longer cartridges to fit properly into standard length actions. Some of the 480 gr (Nitro) 458 bullets however do have the crimp groove far enough forward allowing for an OAL that can fit into a standard action.

    Another issue is the published ballistics re: the "Ackley" cartridges. Ackely was known to publish load data for his cartridges right on the upper ragged edge of dangerously high pressure. I do not use published Ackley data and would never recommend it- especially for dangerous game hunting loads. The data I see for the 450 Ackley Mag is no exception so I would approach it with caution. Plus- what's the point when trying to load for 100% reliable operations in potentially high temperature field conditions anyway??
     
    Last edited: Mar 9, 2018

  7. John P.

    John P. AH Senior Member

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    The 450 Ackley, as I said, is a nostalgia cartridge for me. One advantage of the big BBK action is the magazine is long enough to put that crimp groove where it belongs, at the case mouth. Hmm. A free case capacity increase.

    I know all about PO Ackley and his claims. Chronographs were rare in his early years. I do appreciate his quest for "bigger is better" though and admire his gun smithing skills. I am 71 years old and have read about everything Ackley wrote and the writings about him by others both pro and con.

    Maybe I will write history as I have the Oehler M43 strain gauge system: I plan on pressure testing some of the loads. Will be interesting. Both velocity and chamber pressure at the same time. The M43 is accurate if a guy does his attention to detail in placing the strain gauge in the correct location and knows the chamber wall thickness at the strain gauge attachment point.

    I also have a 450 Watts.

    Building rifles to me is the retirement thing: Keeps me active and exercises my brain. I do not sit in front of a boob tube while the attendants keep a bowl on the TV dinner stand full of "Geyser Chow".

    African Hunter had an interesting article years ago comparing the 450 Ackley, 458 Lott, and a couple other 458's. I printed it off and have it in my files. Do a search, it is well worth the read.
     
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  8. John P.

    John P. AH Senior Member

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    Strain gauge and my 100 pound "sled". Note the chrono screens out past the muzzle. The barrel is purposely small diameter at the chamber to give a good "flex" at firing for the strain gauge to read. 50 Caliber. Yes, the sled does move back a bit at firing. Note the wood strips to allow returning the sled to "battery". There is a big gravel pile in the brush that the bullets go into, nope, I am not spraying lead into the trees. Nearest civilization is 45 miles away.

    Question: If a big bore rifle is fired way out in the deep woods, with no one within hearing distance, is a noise produced?

    [​IMG]

    [​IMG]
     

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    Last edited: Mar 10, 2018
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  9. Tam Dl

    Tam Dl AH Senior Member

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    If nobody is within hearing range I think the more pertinent question is what is the bear doing with your rifle?
     

  10. Shootist43

    Shootist43 AH ENABLER GOLD SUPPORTER AH Legend

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    John P it is obvious that you enjoy taking rifle building, testing and comparison to a whole new level.
     

  11. AZDAVE

    AZDAVE AH Elite

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    It is nice to see the level of testing you are doing. I would rather read one article that is written by someone that does REAL testing and provides a analysed details of the testing methods and data gathered and conclusions. Than a million of the other kinds of articles. I am envious of your testing equipment and location for testing.
    Keep up the great work.
     
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  12. Mick Moriarty

    Mick Moriarty New Member

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    Like Ackley? Build a 17Ackley Hornet, they are a ton of fun and cheap, sleeve the 458WM (sleeve it alone, haha).
     

  13. John P.

    John P. AH Senior Member

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    'Ol Bruin likely will be chewing on the oil soaked stock.
     

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