Regulation: Bullet Weight vs Velocity

Discussion in 'Double Rifles' started by Rick Hill, May 21, 2017.

  1. Rick Hill

    Rick Hill AH Senior Member

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    I have a 458 Win double rifle that regulates best at: 500 grain bullets/2100 fps. It is striking how the groups shrink as you approach 500 gr/2100fps. If I was to develop loads for other (480, 465, 450 and 400 grain) bullets - would it be best to plan for 2100 fps?

    Rick Hill
     

  2. Nosler guy

    Nosler guy AH Veteran

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    Only one way to find out - sounds like you get to do some more shooting - enjoy :)
     

  3. Rick Hill

    Rick Hill AH Senior Member

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    True but a wise and in this case less poor man learns from the mistakes of others! Love to stamp out ignorance especially my own.

    Rick
     

  4. Nosler guy

    Nosler guy AH Veteran

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    No experience with anything that big - but I have done a lot of load development for rifles from .35 down to 6mm - from my experience every one seems to have its own personality - In my opinion, it would be hard to generalize and assume something like that (2100 being the optimum velocity for all bullets). I would suggest that experimenting would be the only real way of knowing
     

  5. Mekaniks

    Mekaniks GOLD SUPPORTER AH Elite

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    If your rifle regulates it well without any sign of over pressure go for it and leave it alone. 500 grains at 2100 is over 4800 ft lbs of energy at the muzzle, which will kill anything on this planet and probebly the next one too:)
     
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  6. Rick Hill

    Rick Hill AH Senior Member

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    I was speaking of only the one gun
     

  7. crs

    crs AH Fanatic

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    Rick,
    In my limited experience, as weight increases, speed decreases, so maybe the converse is true. The lighter bullets might regulate at a higher velocity.
    Some testing will reveal the truth.
     

  8. PaulT

    PaulT AH Elite

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    Rick, for whatever it is worth, my own Verney Carron .500 was factory regulated with Hornady factory 570gn loads which I chronographed at roughly 1950fps - 2000fps.

    My own personal hunting loads were 475gn C.E.B Safari Raptors which hit the sweet spot, regulation, at 2400fps - 2450fps.

    I cannot tell you that this will apply to all doubles and/or across all calibers but that is what happened in my case as well as several other .500 shooters that I am aware of.

    Oddly, between approximately half a dozen .500 doubles, some of different makes, all regulated the .475gn Safari Raptor within 100fps of each other.

    I simply cannot adequately describe the effect the impact of a 475gn Safari Raptor has when it hits a buffalo !
    It definitely leaves a mark !!!!!
     

  9. Double BC

    Double BC AH Member

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    My 450 regulated well with both 500 and 480 grains. The lighter bullets went marginally faster on the upward velocity spread.

    I also had fun working up lighter 400 grain loads with the 75% rule. They were moving faster.
     

  10. AkMike

    AkMike AH Fanatic

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    The 75% rule is "75% of the weight of the regulated load IE 500grns, with a full powder charge". Another respected shooter says 75% powder charge with a full weight bullet.

    I use the full powder charge, light bullet and it works quite well in several doubles.
     

  11. HWL

    HWL AH Fanatic

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    Whenever the barrels of your double rifle do not shoot to the same point of impact, you have a barrel-problem, not an ammunition-problem!

    Those who try to match this problem by changing the powder charge, only can reduce the charge, but not increase.

    Because factory cartidges are generally loaded to top pressures, "improvers" will finally end up with a less powerfull rifle....at best.

    In most cases, the attempt will end up in burning a lot of powder & a frustrated reloader.

    The serious way to solve the problem is to regulate the barrels, in soldering by a gunsmith or by installing an regulating device.

    Soldering means, you fix the problem today, but tomorrow, with another lot of ammunition the problem raises again.

    The "final solution" (some Germans still like the phrase ;)), is an regulation device....

    Pictures show a SxS and an O/U.

    DSC00223.JPG DSC00221.JPG
     
    Last edited: Jun 24, 2017

  12. CTDolan

    CTDolan AH Elite

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    No.

    You're going to be fighting barrel time with the lighter bullets. It's a catch-22 situation...you need recoil on par with the 500 grain load, yet with a lighter bullet this will run contrary to the desire (need) to match the bullet's time traveling the bore. Further, there's the need to watch pressure (which will also go against the objective as, with a lighter bullet, heavy (high pressure) loads will be required to match the system dynamics present when firing 500 grain pills downrange).

    That said, though, these things are an enigma. In other words, it's more art than science (in other words, have at it!).
     

  13. CTDolan

    CTDolan AH Elite

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    If you were shooting a large capacity cartridge, such as Holland's 500/450, you could choose a heavier charge of powder all the while aiming for near 2,100 fps with a 465-480 grain bullet. This would likely work (within reason). But, with the 458 Win Mag, such an option does not exist.

    I say stick with the 500 grain bullets at 2,100 fps. It's perfect, ballistically. Lighter bullets will likely cross, no matter what you do.
     
    Dr Ray likes this.

  14. crs

    crs AH Fanatic

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    HWL,
    What are those devices in your pix?
    Brand and product name?

    ? If they work really well, why are they not in more widespread use?
     

  15. Double BC

    Double BC AH Member

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    They are used on smaller calibers and in some cases lower cost doubles. Not as expensive to finish.
     

  16. Double BC

    Double BC AH Member

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    Barrel time is a function of not only recoil but velocity. What position the barrel is whipped in relation to the bullet exiting. Lighter bullets create less recoil for less whip but exit the barrel faster. It is possible to match the point of impact of the lighter bullet with Increased velocity. I needed about 2200 to 2300 fps to regulate 350 -400 grain bullets out of my 450 NE.

    NOT SURE HOW THE PRESSURE AFFECTS THE 458 win.

    Honestly except for practice I just went back to the standard loading 500 grains at 2150 fps (480 grain). It's just easier and these are the loads that made them famous.
     

  17. CTDolan

    CTDolan AH Elite

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    That's what I was trying to say, albeit somewhat clumsily.
     

  18. crs

    crs AH Fanatic

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    DoubleBC,
    Thanks.
    My reason for asking is that such a device could reduce the labor in making double rifles from double shotguns. Since the shot gun actions are always fitted to a new set of barrels, the regulation device could become a part of that process. It would also allow the rifle owner/shooter to re-regulate the gun himself, much as does the Baikal DR.
     

  19. HWL

    HWL AH Fanatic

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    They come from a bavarian gunsmith, but you can order even your Heym double from the factory with this...

    They are not really cheep, 1500 €, but they work perfect.

    Whenever you change your ammunition, you simply screw... ...perfect regulated.

    HWL
     

  20. Double BC

    Double BC AH Member

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    They are interesting, looks like they work well.
     

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