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Thread: Primer brands v. 500 S&W?

  1. #1
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    Default Primer brands v. 500 S&W?

    In reviewing loads for the 500, I see that people always list the LR primer that they used ...are there rules for interchangeability in primers? I know some are hotter than others and what not, but I'm a newbie at this. For example, there's one load that I saw with CCI LRM primers, but I own Fed 210M primers ...any problem in using the Feds? What's the story on primers and how they differ, i.e. in terms of chamber pressure and velocity?

    Thanks,
    Brian

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    As long as you use starting loads and work up you should do fine with your primers.

    http://www.jamescalhoon.com/primers_and_pressure.php

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    Default Primers and loads

    Brian,

    The first loading manual I ever bought had advice on primers:

    Any time you change primers (especially switching from, for instance, standard primers to magnum primers) back off your powder charge at least 10% and work up your loads a little at a time watching for signs of exessive pressure.

    The primer is the first step in internal ballistics and literally sparks off everything that happens after the hammer falls. If a primer torches off only 10% of your powder in the first microsecond, the pressure curve will be considerably different than if 20% is lit at the beginning.

    Just like the "flame front" inside the cylinder of an internal combustion engine, if it moves too fast, can cause pinging or "knock" or even blow a hole in a piston, if too much of your powder burns before the bullet moves far enough down the barrel, you can get a terrific spike in pressure that can even blow up a chamber. Think about this: Develop a load that gives near-maximum pressures using a standard primer. Then use the same powder with a primer that holds 50% more priming compound (like a magnum primer, but don't quote me on the percentage) The powder in the cartridge is BOUND to burn faster and develop higher pressures right away even if they fall to normal by the time the bullet exits the barrel.

    The primer, though small, is every bit as important to the pressures of your loads as the bullet, the powder, the brass. You do know that if you switch brass, you do the same thing, too, right? On the good side, if your loads are NOT near maximum you are probably OK. But always err on the side of caution. Even the bullet lube can make a difference, though maybe THAT is going a little too far.

    Larry

    Quote Originally Posted by tananaBrian View Post
    In reviewing loads for the 500, I see that people always list the LR primer that they used ...are there rules for interchangeability in primers? I know some are hotter than others and what not, but I'm a newbie at this. For example, there's one load that I saw with CCI LRM primers, but I own Fed 210M primers ...any problem in using the Feds? What's the story on primers and how they differ, i.e. in terms of chamber pressure and velocity?

    Thanks,
    Brian

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    Quote Originally Posted by Lost Sheep View Post
    Brian,

    The first loading manual I ever bought had advice on primers:

    Any time you change primers (especially switching from, for instance, standard primers to magnum primers) back off your powder charge at least 10% and work up your loads a little at a time watching for signs of exessive pressure.

    The primer is the first step in internal ballistics and literally sparks off everything that happens after the hammer falls. If a primer torches off only 10% of your powder in the first microsecond, the pressure curve will be considerably different than if 20% is lit at the beginning.

    Just like the "flame front" inside the cylinder of an internal combustion engine, if it moves too fast, can cause pinging or "knock" or even blow a hole in a piston, if too much of your powder burns before the bullet moves far enough down the barrel, you can get a terrific spike in pressure that can even blow up a chamber. Think about this: Develop a load that gives near-maximum pressures using a standard primer. Then use the same powder with a primer that holds 50% more priming compound (like a magnum primer, but don't quote me on the percentage) The powder in the cartridge is BOUND to burn faster and develop higher pressures right away even if they fall to normal by the time the bullet exits the barrel.

    The primer, though small, is every bit as important to the pressures of your loads as the bullet, the powder, the brass. You do know that if you switch brass, you do the same thing, too, right? On the good side, if your loads are NOT near maximum you are probably OK. But always err on the side of caution. Even the bullet lube can make a difference, though maybe THAT is going a little too far.

    Larry
    Larry,

    That's a good description and good advice.

    Just to clear up a point about the big 500. Brass for it is now designed for Large Rifle primers. Rifle primers need a deeper pocket to seat correctly. I have developed loads using Federal 215 and CCI-250 primers (LR magnum) . I found magnum primers to give more uniform ignition when there was air space in the case, when using the extruded powders such as N110. Some of the earlier brass for the S&W 500 was dimensioned for large Pistol primers and was meant to be used with LP primers, magnums, of course. I think the rifle primer brass is marked with an R for rifle primers. The Hornady Loading manual states that "all 500 S&W loads were developed with Large Pistol primers.." I assume LP magnums.

    I would highly recommend the use of rifle primers IF you pursue the highest performance from this cannon. The maximum average industry accepted pressure for this one is 60,000 psi. Rifle pressure for sure and rifle primers have thicker cups to withstand this pressure. Keep the pockets clean and make sure primers are seated .002-.004" below flush Things work better when the primers are bottomed out and not rubbing on the recoil face. If you use pistol primers in rifle pockets there will be likely be misfires.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



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    Thanks. While on 'vacation' the last week or so, I ready everything in the Hornady manual up to the reloading data and got a pretty good introduction there even though the focus is mostly on bottle-necked rifle cartridges.

    More questions:

    1) I'm planning on using Federal 210M primers for my .30-06 reloads and would like to use the same for the 500 ...see any problems with that? Only have to stock one kind of primer that way.

    2) I bought each and every tool that folks have suggested, including the primer pocket uniformer. If I use this, will the fully-seated primers end up just below flush as Murphy recommends? Or should I measure it? How? Wire type feeler gauges? Pointy caliper to measure the area outside the primer pocket then measure on top of the primer?

    BTW, the 2007 Hornady Reloading Annual Manual that's been on the shelves for quite some time (and I now accidentally have 2 copies of) has a pretty good article on reloading the 454, 460, and 500 magnums, including a discussion of brass and a bunch of other hints, etc. To keep things simple, I'm using only 'R' marked brand new Starline brass. It has the least case capacity of those measured in the article, but I'm not going to hand load maximum rounds ...at least not for some time. I'll just buy a box or 2 of Buffalo Bore with hard-cast gas-checked WFNs for now.


    Brian

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