Quantcast

300 Win Mag Bafflement

Discussion in 'Handloading and Reloading' started by Shmackey, Jul 22, 2018.

Thread Status:
Not open for further replies.
  1. Shmackey

    Shmackey Member

    Joined:
    Dec 24, 2002
    Messages:
    1,496
    Location:
    Colorado
    I've been loading pistol and rifle for about 10 years now, never came across this issue. This is my first belted case, for what it's worth.

    I got new Hornady 300 WM brass, full-length sized it in a standard RCBS die. Checked trim length, chamfered, deburred. Tumbled clean. Primed. Drops into my Lyman case gage like butter. Dropped powder, seated a 200-gr Sierra GameKing, and about a third of them hang up in the case gage right around the web. So they're almost in there, but not.

    I'm not sure if they're hanging up on the web, the shoulder, the mouth, or what. Caliper measurements of those places seem identical to the cases that still gauge like butter after bullet seating.

    Further details:

    RCBS standard seating die
    COAL standard 3.34
    Lee Classic Cast Press
    Elevation 8900 feet
    Zodiac sign Aries

    I'm loading these for a buddy's hunting rifles, so nothing creative going on. I'm not crimping these rounds since (as far as I know) there's no reason to. I'd experiment with that, but I don't even have a crimp die in this caliber. I just set the bullet seater to create the SAAMI OAL and called it a day.

    Ladies and gents, what is going on?
     
  2. Ireload2

    Ireload2 Member

    Joined:
    Mar 19, 2009
    Messages:
    196
    Do they chamber?
    You do not shoot them from a gage.

    BTW All RCBS conventional seater dies have a crimp shoulder. You are probably crimping inadvertently.
    I suspect you might normally be a LEE die user. Only earlier Lee dies from before the factory crimp dies have an internal crimp shoulder.
    RCBS does not make or need a separate crimp die.

    You might paint an offending case with a permanent black marker an see where it hits the gage.
    You should also read RCBS set up instructions for their seater dies.
    Basically you install the die with it backed away from the case a few turns.
    Run the ram up full with a case in the shell holder. Then run the die down until it touches the case with the crimp shoulder. Then back the die up about 1/4 to 1/2 turn so none of your brass can ever hit the crimp shoulder. Then you will never bulge a case by accident. This applies to all die brands with an internal roll crimp shoulder in the seater.
     
    Last edited: Jul 23, 2018
    FROGO207 and entropy like this.
  3. Shmackey

    Shmackey Member

    Joined:
    Dec 24, 2002
    Messages:
    1,496
    Location:
    Colorado
    Good question. Right now I have just the gauge. But _something_ is happening to the brass during seating to take it from "go" to "no go" as far as that gauge is concerned.

    I think you're on to something with crimping inadvertently. I actually don't use Lee dies except for their FC dies for pistol. But that doesn't mean I didn't have a brain fart when I casually set up the seater die, concerned only with OAL. I may very well be crimping enough to push the shoulder outward a hair.

    In between my first post and this one, I had an "aha" moment where I realized I didn't think about the built-in taper crimp. So I re-set-up the die from scratch to give a typical amount of crimp. And it didn't help. But maybe (it occurs to me now) I really need to set it up intentionally with zero crimp and see what happens. I'll do that in the morning.
     
    horsey300 likes this.
  4. Varminterror

    Varminterror Member

    Joined:
    Jul 17, 2016
    Messages:
    8,638
    Magic marker may or may not reveal witness marks on cartridge brass. It usually does, but it can lie to you. Witness fluid or soot, however, are the answer to determine your gauge issue.

    I’m with the others, however, if it chambers without bolt resistance and fires, then you’re imagining a problem for yourself where one is not.
     
    horsey300 likes this.
  5. Shmackey

    Shmackey Member

    Joined:
    Dec 24, 2002
    Messages:
    1,496
    Location:
    Colorado
    Ok so two updates on this:

    1. I set up the seating die with zero crimp. It still produces rounds that sometimes won't gauge even though they did before bullet seating. I don't think it's because of the new neck width (with bullet in neck), as all the necks mic the same. Also, when they don't gauge, it's not a subtle tight squeeze. It's as if the case mouth is hitting the end of the chamber hard and early--or the belt is hitting the front of the chamber hard and early.

    2. I had my buddy chamber good and "bad" rounds in his rifle. They all chamber like butter. So indeed this is a non-issue, but I sure would love to understand what's going on with those occasional "bad" rounds during bullet seating.
     
  6. entropy

    entropy Member

    Joined:
    Feb 9, 2004
    Messages:
    10,682
    Location:
    G_d's Country, WI
    ...and this is why I use a barrel for a gauge, and not a gauge.
     
    horsey300 likes this.
  7. Slamfire

    Slamfire Member

    Joined:
    Dec 29, 2006
    Messages:
    10,684
    Location:
    Alabama
    I took a look at a picture of a Lyman 300 Win Mag case gage, and the thing is non adjustable.

    I have been using the adjustable L.E. Wilson type gages in setting up my dies. Here is a picture of one

    p_749011855_1.jpg

    And this is a video on how to set up the die



    The base to shoulder distance of a belted magnum is not standardized and neither are the base to shoulder distances found in rifle chambers. So, the first thing I am going to comment on, is that you really don't know how much you have pushed the shoulder back, with your RCBS die, from the rifle chamber that the round will be used in.

    These case gages are only measuring base to shoulder distances, they are usually cut large between base and shoulder and it is unusual to have a case so fat that they stick in the die. But it happens.

    Then, something is going on as you seat the bullet. I think you are buckling the case when seating the bullet, that has happened to me. I was never able to measure it, never found the exact location where the interference fit happened, just observed the phenomena when using chamber reamer cut case gages. These case gages were cut with the same reamer as used in my match barrels, so they are dimensionally correct in length and width. The "cure" has been a small base die. Increasing the clearance between case and chamber resulted in less binding after inserting the bullet. You can try greasing the bullet or case neck before seating the bullet and see if that makes a difference.

    I doubt you removed the firing pin mechanism and the spring loaded ejector, or, the extractor in testing your rounds. Spring tension from any of these components will disguise tight fitting rounds, which is why when you do a chamber check, all this stuff needs to be removed. Older mechanisms with claw extractors and easily removed firing pin assemblies provide much better feel when checking a round in a chamber. I regularly remove the firing pin assemblies in Win M70's, M98's, M1903's, when conducting round to chamber checks, and these actions don't have spring loaded ejectors either.
     
    FROGO207 likes this.
  8. FROGO207

    FROGO207 Member

    Joined:
    Dec 7, 2008
    Messages:
    8,949
    Location:
    Mount Desert Island Maine
    I also think you are buckling the lower part of the case shoulder when you are pushing the bullet into the case due to the necessary interference fit to get good tension. You say that you chamfered the case mouth. Did you do it on the inside as well? Breaking that sharp edge will help prevent this from being such an issue. I use a VLD reaming tool on the inside of my rifle brass and this seems to help keep good tension without collapsing the shoulder, especially with those that have thin necks like 30-30.
     
  9. Shmackey

    Shmackey Member

    Joined:
    Dec 24, 2002
    Messages:
    1,496
    Location:
    Colorado
    I did do the insides, but what you're saying could still be happening. Do certain seating dies do a better job than others of supporting the case during seating?
     
  10. FROGO207

    FROGO207 Member

    Joined:
    Dec 7, 2008
    Messages:
    8,949
    Location:
    Mount Desert Island Maine
    You are not trying to support the case you are trying to square the bullet in the brass when you seat it. Some here say that certain brands of dies are better than others and the competition or specialized dies are better yet, but I just use regular Lee or RCBS dies with good results. But you still may need to get a custom built insert/punch (or make your own) for your seating die to fit your bullet better. All companies will make them for you for a price. I have even waxed up the bullet and put JB weld in the cavity of the die and made a custom punch as a temporary answer. I use the VLD reamer as it gives a long gradual taper to the inside of the brass and seems to allow easier bullet seating. Also using slow steady pressure to seat the bullet seems to work better for me than placing the bullet and cranking the handle hardish. Some say using a bullet with a tapered base (boat tail) rather than a flat base works better as well but I have not had problems seating flat base bullets squarely in the neck. If you want to see if the bullet is in the brass straight (no runout), lay the finished round on a flat surface and roll it while watching the tip of the projectile. If there is no wobble or movement of the point the bullet is seated straight for practical purposes as you are not loading for 1000 YDS yet I assume.;). you could measure your expander ball in the sizing die and see if it is around .002 smaller than the bullet. That is what I like my casings to end up sized to for good bullet tension when inserted.
    So at the end of the day (and my long winded explanation) if the rounds chamber with no difficulty there is not really a problem with using the ammo in the firearm.:cool:.
     
    Last edited: Jul 26, 2018
    horsey300 likes this.
Thread Status:
Not open for further replies.
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice