30-30 Crimp

Discussion in 'Reloading Room' started by lklawson, Sep 25, 2015.

  1. lklawson

    lklawson Staff Member

    As I get a handle on reloading, I intend to do some for family members as well. Dad has an antique 30-30 lever-gun. Eventually, I'm going to pick up dies for it. It got me thinking; this thing is a tube-magazine. Does it make sense to Factory Crimp the bullet to prevent bullet setback due to butt-to-nose spring pressure in the tube? Or am I over-thinking this?

    I'll probably still buy the 3 die set anyway when I get to that point, but how critical is the FC for tube mag fed cartridges?

    Peace favor your sword,
    Kirk
     
  2. Fracman

    Fracman Member

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    Yes a roll crimp is what I use in this application
     

  3. FlashBang

    FlashBang I Stand With Talon Lifetime Supporter

    For 30-30 rounds that will be used in a lever action where they are against each other, I would crimp. There are two types of crimp: roll crimp and taper crimp.

    A roll crimp should, in my opinion, only be used with bullets that have a canelure. Because the canelure is small and in a fixed location on the bullet, it is important that all the cases be trimmed to the same length so that when you seat the bullet, the crimp will be applied at the same location, in the canelure. A roll crimp is typically used for revolver loads and other firearms where the cartridge head spaces on the rim.

    A taper crimp is used to remove the belling done to the case mouth and is used mainly for cases that headspace on the mouth of the case. The Lee FCD is essentially a taper crimp die but it adds more pressure to the neck to really seal the mouth to the bullet without shrinking the mouth to the point where it no longer properly head spaces.

    The choice of the type of crimp you use is pretty much up to you.
    I crimp my pistol and revolvers rounds, but don't crimp my rifles rounds unless they will be used in a lever action or tube feed.

    .
     
  4. ajole

    ajole Supporting Member

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    Yes, the tube magazine requires a crimp. The Lee factory crimp "should" be good enough, but if you want to be sure, the roll crimp is tighter.
     
  5. You are actually under-thinking crimp. You really want to think about it as setting bullet pull instead of crimping.

    Beyond keeping the bullet from moving, crimping is done to create a more consistent pressure curve from round to round. Getting the best pressure curve is what people are trying to do by weighing every powder charge, varying OAL, etc. The amount of bullet pull or lack of bullet pull changes the real world mass burn rate.

    Out of a rifle figure an easy 0.5 smaller group minimum by using the proper bullet pull by whatever method is used to get the near perfect bullet pull.

    There is a reason it's called FCD and a reason that ammo factories crimp them. Factories haven't been doing it for over a 100 years because they want added expenses.

    There is a safety factor in setting bullet pull when using powders that are made to well at ignite slightly higher pressures when used in certain rounds. Like the well known gun damager Blue Dot in 9mm, .357 mag, etc.

    Also if one doesn't want to have several different powders on hand, it allows one to get a very practical good accuracy by using a powder that is less than optimal for a given caliber. It also allows using bullets in a given gun that wouldn't otherwise be suited for it. A FCD isn't an expense, but a money saver.

    To each their own. But one has to decide why are they reloading. Is it to save $? Is the reloading itself the pursuit? Ensure an ammo supply? All of these?

    See both Lee's reloading book and G. Frost's book "Ammunition Manufacturing". Here is some links set getting thinking.

    https://www.shootingsoftware.com/pressure.htm

    http://bulkreloadingsupply.com/

    http://ar15armory.com/forums/topic/...lized-pic-heavy-and-long/?hl=consistent crimp
     
  6. A FCD will cut a grove into a bullet and roll crimp won't. You can only way to get more bullet pull than a with FCD would to to add an adhesive when using a FCD.
     
  7. lklawson

    lklawson Staff Member

    Thanks guys. Great information. I appreciate the input. :)

    Peace favor your sword (mobile)
     
  8. Branth

    Branth Member

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    I had always heard it the other way around - You can over-crimp with a roll crimp die and embed the case mouth into the bullet, but the lee FCD can't over-crimp because of the collet mechanism.
     
  9. Cutting a grove into a bullet isn't necessarily over crimping. At least some old military rounds and all of them I have taken apart will have an indentation on the bullet from using the 3 point crimp die.

    That said, Lee's reloading book(page 44 in mine) says that the FCD will do it and I have done it. I have never tried to do it with a roll crimp die as I haven't used one since I got my 1st FCD.

    Also in the Lee book I have, he quotes some of what G. Frost says about crimping. In part G. Frost says that one doesn't want a bullet to move until at least 1000 psi is reached. Which makes sense to anyone who has studied the details of powder ignition, burn rates(both linear and mass), pressure curves, etc. It takes 100 lbs of bullet pull in a .308 for that to happen.
     
  10. MXGreg

    MXGreg Supporting Member

    Not to get off topic.....

    I've used Blue Dot for both 9mm and .357 mag, what damage are you talking about?
     
  11. undeRGRound

    undeRGRound ROLL wif Da MOLE! Supporting Member

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  12. Look and see on this forum how many of the Hipoints that have broken or cracked were using reloads with Blue Dot. The guy who pushed it here on this forum even ruined his Hipoint with it. I think he ruined some Glocks with it also, but he might have been doing some other thing with them that he didn't understand. I've always wondered why anyone would get reloading advice from someone who ruins guns on a routine basis with bad reloads.

    Nation wide enough .357 mag revolvers suffered damage from reloads using Blue Dot that Alliant said not to use it for .357 mags.

    Blue Dot has for decades been known to have unstable ignition compared to most other powders. Indeed Blue Dot can be and is used safely, but one has to understand the nature of it and reload with it accordingly.

    I wouldn't say this is fully off topic, as Blue Dot is great example of why bullet pull is important. Bullet pull, without question, gives a more stable and predictable ignition.

    The burn rate of all powders changes as the pressure changes and it isn't a straight and smooth line. Some powders have a straighter and smoother line others.

    On the low end, middle and high end Blue Dot's pressure curve line isn't smooth. It has sudden flat line and sudden spikes in pressure. That is why one needs to be a more careful with it than say with Unique to stay out having a problem.

    Personally I came to the same conclusion as many have before I did. If one has to try and get everything they can out of caliber to meet a need, it's time to get a bigger gun.
     
  13. ajole

    ajole Supporting Member

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    That's absolutely not true. FCD will not cut anything unless it's mis-adjusted, and roll crimps actually bend metal into a groove, rather than depending on simple friction as the FCD does.


    Well...there is a reason, but you don't seem to understand it. It has nothing to do with pull weight, cost, or ruined brass.

    They do it that way because you can't roll crimp anything that head spaces on the case mouth, which is most modern semi pistol rounds, and for rifles, because you can't roll crimp any bullet without a cannelure, meaning if they want to use many of the best bullets out there, they cannot roll crimp, even if they wanted to.

    You seem to be overthinking the crimp.

    Sure, that's true of all reloading, isn't it?

    There's a ton of low pressure/low velocity rifle loads for Blue Dot. You have to avoid double charges, but at low velocity, blue dot seems to work well. Often won't function in a semi, but shoots slow, quiet, and accurate.

    In a pistol...it's as you say.

    Not that this has anything to do with crimp, really.
     
  14. greg_r

    greg_r Lifetime Supporter

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    The Lee FCD will damage your bullet IF you set it up wrong, just like a roll crimp will. Imagine taking a belt and clinching it around your waist too tight. A crimp works the same way. You can check the damage of a misadjusted crimp with dial calipers or a micro light.

    Copper has more spring than lead so the core of the bullet will actually be damaged more than the jacket. The biggest problem with this will very accuracy problems.

    Plated bullets can actually have the plating cut.

    Naysayers will say it does not matter because the bullet is "damaged" when it hits the rifling anyway. This is also not true, the bullet is not damaged but uniformly swaged. If this were not true accuracy would be non existant.

    As a general rule I crimp anything fired in a revolver, a tubular magazine, or, usually but not always, a self loader. Anything to be crimped will have a cannelure. Non-cannelured bullets are not meant to be crimped. My main reason for crimping is to prevent bullet setback or bullet pull. In other words, reliability and safety. Loads for my single shots are almost never crimped.

    Crimping can have an effect on performance as noted in other posts, but properly loaded target ammunition is not crimped. From my bench rest shooting days I can say that no match was ever won with crimped ammunition.
     
  15. G. Frost set 2 successful commercial ammo factories in 2 different countries. Before that he worked for Olins for 30 years, mainly in the ammo area and at one time was in charge of quantity control. You have set how many ammo factories? You have how many years experience in commercial ammo loading? You've written how many books of how to setup and run and ammo factory? Do you have test equipment to check pressure curves?

    I'll go with what 2 acknowledged experts have to say about crimping, bullet pull, etc over some guy who a reloaded a few 1,000 rounds of ammo.
     
  16. It depends on the what the target shooting is. Ammo for bench rest it isn't. For things like 2 gun match target shooting the ammo is crimped.
     
  17. From G. Frost's book "Ammunition Making" and found of pages 99 and 100.

    "A necessary control in all metallic ammunition is that of bullet pull.

    The amount of force needed to pull the bullet from or push the bullet into the case has an effect on ignition, velocity, pressure, and accuracy from the ballistic side."

    "a light crimp may lead to uncertain ignition"
     
  18. GoesBang

    GoesBang Supporting Member

  19. ajole

    ajole Supporting Member

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    Geeze...defensive much?:p

    What EXACTLY did G. Frost tell you about WHY factories don't use roll crimps? Because that's what I was talking about.

    Go ahead, show us the quotes where he says I'm wrong. Betcha can't.

    But I don't give a crap what you say about what G. Frost said, because I didn't say anything about what HE said, I said YOU are wrong. And I didn't say you were wrong about bullet pull. I said you were wrong about relative strength, why they use taper crimps, and cutting brass with taper or factory crimps. Because, you are totally, irrevocably wrong.:rolleyes:

    Just because you mention reading some expert about one thing, then make a proclamation about something else, doesn't make you right about what the discussion was really about.

    Talking about bullet pull....no one here but you is even into that! Kirk just wants to stop his bullets from suffering setback, the revolver guys are all about that, and it's opposite as well. Sure, consistent crimp is good for accuracy, no freaking duh..but roll and taper can both do that, and BOTH do it tight enough to provide the pull weight you seem to insist is the only thing one needs to worry about.

    Seriously....it's like you are quoting Spielberg about Sci Fi, then saying Starship Troopers was the only great Sci Fi movie...and expecting everyone to buy your opinion because you mentioned a guy.:rofl:
     
    Last edited: Sep 28, 2015
  20. ajole

    ajole Supporting Member

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    So what? I mean, it's a sort of true statement...but who cares?

    No one here said to light crimp. What's your point?

    Here's an equivalent statement, with just as much application to the discussion...

    "Hard primers can lead to uncertain ignition."

    But see...no one was talking about hard or soft primers, either.:rolleyes: