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Thread: Bullet diameter - How big is too big? 30 BR

  1. #1
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    Bullet diameter - How big is too big? 30 BR

    I'm trying to get started in 30BR, VFS.

    I have a new Krieger 1-17 barrel that was marked 300 / 308. What meaning does that have?

    AND
    My concern is that I have some Lapua 100 grain 30 cal bullets. I have measured them and they measure .3089 - .3090 Is that OK? What do most 30 Cal bullets used for Benchrest measure?

    Does anyone have any experience with these bullets and would they be competitive? Their ads claim they are BR bullets.
    Last edited by jimsplce; 02-27-2022 at 03:39 PM.

  2. #2
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    Quote Originally Posted by jimsplce View Post
    I'm trying to get started in 30BR, VFS.

    I have a new Krieger 1-17 barrel that was marked 300 = land diameter / 308= groove diameter. What meaning does that have?

    AND
    My concern is that I have some Lapua 100 grain 30 cal bullets. I have measured them and they measure .3089 - .3900. Is that OK? YES, that is OK What do most 30 Cal bullets used for Benchrest measure?

    Does anyone have any experience with these bullets and would they be competitive? Their ads claim they are BR bullets.
    I have no experience with these bullets but the sizing is correct

  3. #3
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    CIP 30br spec

    .300 & .308 refer to the nominal bore size (lands) and the rifling groove diameter respectively.

    Interestingly, CIP specification lists a 7.82mm (.3079) projectile max diameter for a 30br whereas for .308 win it is 7.85 (.3085)
    Last edited by Davester; 02-27-2022 at 07:07 AM.

  4. #4
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    The BIB bullets that I shoot in my 30BR measure .3086 at the pressure ring.

  5. #5
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    I have no experience but the sizing is correct?????
    There is a huge difference between .3089 and .3900
    Is that a typo Alinwa missed?

  6. #6
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    Quote Originally Posted by FBecigneul View Post
    I have no experience but the sizing is correct?????
    There is a huge difference between .3089 and .3900
    Is that a typo Alinwa missed?
    I am not a Grammar Nazi. That said, I would not rise to your bait in any case

  7. #7
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    Quote Originally Posted by FBecigneul View Post
    I have no experience but the sizing is correct?????
    There is a huge difference between .3089 and .3900
    Is that a typo Alinwa missed?
    It's a fair question but should be directed to me.
    It should be .3089 - .3090.

    I will change that in my original question.

    Whether Alinwa missed it or felt sure what I meant I don't know, but sure appreciated the reply.

  8. #8
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    The only thing you need to worry about is your loaded round size versus the chamber neck size.

  9. #9
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    Yes, I am aware of neck size consideration. My chamber neck size is .330 and I will target .228 for neck diameter.

  10. #10
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    Ok, another novice question.

    I'm using Lapua 6BR brass and expanding the neck using a Harrel's expanding die to 30 Cal.

    I also have a 7mm mandrel along with the 30 mandrel. Is it beneficial to expand in two steps as opposed to one or is there a down side to doing that?
    Also, When I expand the case, I get a slight ridge or doughnut inside the case at the neck shoulder junction. It doesn't interfere with the neck turning, but there is a small ridge. Is it recommended to use a separate reamer. or in my case, a pilot with a cutter to remove it?
    I'm aware of the doughnut on the outside, but this is inside.

  11. #11
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    Quote Originally Posted by jimsplce View Post
    Ok, another novice question.

    I'm using Lapua 6BR brass and expanding the neck using a Harrel's expanding die to 30 Cal.I would like to propose an entirely different method

    I also have a 7mm mandrel along with the 30 mandrel. Is it beneficial to expand in two steps as opposed to one or is there a down side to doing that?There is a downside. Every time you stretch brass and stop it work-hardens. It is generally best to move brass in one motion. When I neck cases up or down so much that it requires multiple operations I find it best to anneal between moves.
    Also, When I expand the case, I get a slight ridge or doughnut inside the case at the neck shoulder junction. It doesn't interfere with the neck turning, but there is a small ridge. Is it recommended to use a separate reamer. or in my case, a pilot with a cutter to remove it?I own three different brands of piloted inside neck reamers designed to do exactly what you propose and have never gotten sasisfaction from any of the three.
    I'm aware of the doughnut on the outside, but this is inside. Donuts are formed on the inside and need to be ironed to the outside

    OR... to try something completely different;

    I find best results via blowing the necks out with an appropriate gunpowder charge instead of mandrelling up...... and then onto a mandrel for turning, a mandrel which pushes the donut from inside to outside and you turn it off the OUTSIDE instead of trying to ream it.


    Here's how I would go about making cases for 30BR (having never done it)

    #1-load a primed case up to the base of the shoulder with Clays shotgun powder, roll a little wad of paper towel to plug the neck and fire it into the air...NO BULLET!!!

    check your results. Add/reduce powder charge.

    You might find that you run out of powder room before achieving satisfaction in which case you have two choices, a heavier plug than the paper towel (wax, play-dough, modeling clay) or a faster powder (Win WAALite or Norma R-1)

    report back






    Meantime, maybe this will spur some of the actual 30BR shooters to respond to your question

    We can hope!

  12. #12
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    Thumbs up

    Quote Originally Posted by Wayne Shaw View Post
    The only thing you need to worry about is your loaded round size versus the chamber neck size.
    "And here, you have it" - Wayne is correct.
    Adding to Wayne's statement, with proper loaded-round/chamber clearance & judicious load development, bullets, up to, at least, .310" diameter work pretty well . . . don't ask me how I know . . . Of course, with longer bullets, requiring some free-bore, a wider free-bore may also be desirable. RG

  13. #13
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    I agree the ideal way to fire form the case in 30BR would be to have a fire forming barrel and use a fast powder. However, I don't.

    I'm guessing that not too many 30BR shooters have fire forming barrels because there aren't that many "shot out" 30BR barrels like in the PPC world.

    Right now I'm at the stage of working on getting cases fire formed that have been fired 3 times to send off to get a sizing die made.

    For a novice this is a challenge trying to get a custom sizing die without having a die to use for reloading the cases I'm trying to make.

    It isn't the first firing that I'm unsure of, it's what to expect for the next two firings.

    My concern is having bullet tension for the next two firings without having a die to size the neck to hold the bullet. I'm planning on placing a neck sizing bushing on the case and using an arbor press to create enough tension to at hold the bullet. Is there a better way? The bushing I plan to use is a .328, does that sound reasonable for this operation?

  14. #14
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    If your chamber is 0.330" at the neck and you're aiming for a loaded round of 0.328", you need a smaller bushing. Try 0.324" or 0.325" and seat the bullet long. It'll get pushed back and jam into the lands. This'll hold the case head firm against the bolt face. Just be sure to lube your bolt lugs well.

    -Lee
    www.singelactions.com

  15. #15
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    Quote Originally Posted by jimsplce View Post
    I agree the ideal way to fire form the case in 30BR would be to have a fire forming barrel and use a fast powder. However, I don't.
    For all reading this who didn't understand my explanation, this IS NOT ABOUT FIREFORMING IN AN OLD BARREL WITH FAST POWDER!

    My intent is/was to propose fireforming with SHOTGUN or PISTOL powder and no bullet right in your own barrel. No special preparations necessary.

    I'll back out now because this scares me..... I do it all the time but I absolutely know for a fact that pistol powder and a bullet will make you dead. Because I know two brothers of a man DEAD from this.

    I'll


    STOP

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