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Thread: Same Wt. Bullet, different construction, Much difference in powder Load ??

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    Member kodiakrain's Avatar
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    Default Same Wt. Bullet, different construction, Much difference in powder Load ??

    I've been wondering if you guys see much difference in the loads developing for two bullets that are the same weight but of different construction, as in the tip, or Boattail vs. Flat base

    For example, in a .277 bullet for .270wsm, I have a box of Nosler 140gr Accubond Spitzer, and also 140gr Partition Spitzer (sectional Density exactly the same, Ballistic coefficient quite different, so..)

    the weight is the same but shape, distance to lands, etc. fairly different.
    So, if I work up a fine load for the Accubond, will I be able to start close to that same grain load for working on the Partition ??
    Or, is it start all over again.

    Working with .308 bullets in 180gr, for 30-06 lately I found the diffference to be very close between a Speer Round Nose, and Mag Tip (tho those are nearly identical bullets) and also a Hornady SST Interlock, which is a boattail, the others are not (that ideal load was very close to the Speers)
    (in fact for IMR 4350, all 3 were at either 54 or 54.5 as best for accuracy)

    I'm thinking I can take some short cuts on going all the way back to Minimum and working back up with the differently constructed bullet,yet, same powder, rifle, etc.

    What have you guys seen on this ?
    Ten Hours in that little raft off the AK peninsula, blowin' NW 60, in November.... "the Power of Life and Death is in the Tongue," and Yes, God is Good !

  2. #2

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    In my experience it boils down to difference in bearing surface with different profiles. Some just have more metal striking the bore even though they weigh the same. I don't have much experience with the newer Barnes and such, but I have to guess that their long length translates into lots of extra bearing surface. I'd reduce charges way down with them and work up, just in case.

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    Except for an all copper bullet, if the loads are near max, I'd drop 5% and work up again.

  4. #4

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    It's been a while since I looked at a Nosler book, but I thought they always listed both the Accubond and Partition together as interchangeable as far as load data goes.

    That may not answer your question for all cases, but it should for the specific example.

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    Member kodiakrain's Avatar
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    Quote Originally Posted by evandailey View Post
    It's been a while since I looked at a Nosler book, but I thought they always listed both the Accubond and Partition together as interchangeable as far as load data goes.

    That may not answer your question for all cases, but it should for the specific example.
    Yes, they do list them on the same page for load data,

    I was figuring, you would have to work a load out for each different bullet as they technically would fly differently (?)

    Not sure that makes sense, but, (different Ballistic Coefficient, you know, a boattail, would sail quite a bit differently than a flat base, right(?) isn't that why they list the BC of the bullet, even tho on the same page, same powder data "to start with" but that each bullet is actually unique?
    that is the core of my question.

    It seems even if you had an exact load worked out for an Accubond,
    it would not necessarily be best for the same wt. Partition, or not ??
    Ten Hours in that little raft off the AK peninsula, blowin' NW 60, in November.... "the Power of Life and Death is in the Tongue," and Yes, God is Good !

  6. #6

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    Quote Originally Posted by kodiakrain View Post
    It seems even if you had an exact load worked out for an Accubond,
    it would not necessarily be best for the same wt. Partition, or not ??
    In my experience, almost certainly not. Sometimes it happens, but more often different brands and styles of bullets in identical weights will shoot a little differently. One of my 250 Savages with 100 grain bullets is the worst I've ever seen. Each brand demands its own max, and infact has a different accuracy load. Could be because it has a slender barrel, and could be due to the longer throat. But there you have it.

  7. #7

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    Perhaps interchanging load data would not necessarily produce best flight characteristics in both, but I was always under the assumption that interchanging between the two would be SAFE. Maybe I am wrong. You've got me curious now.

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    Member kodiakrain's Avatar
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    Yeah, evandailey, I am fairly sure it would be safe, (maybe not if up at max loads tho)

    but it is about accuracy, and even velocity produced, that I am interested in

    Thanks guys, I'll be learning all about it more as I work on this 140 grain set,
    maybe if I remember I'll post the comparison results,

    mauserboy, what are you referring to in your mentioning "except for all copper bullets," how does that affect things?
    I don't work with Barnes much as a result of the fouling problem I feel they gave me, but am definitely interested
    Ten Hours in that little raft off the AK peninsula, blowin' NW 60, in November.... "the Power of Life and Death is in the Tongue," and Yes, God is Good !

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    You really can't tell for sure until you actuall try them. I probably wouldn't go all the way back to starting loads, but I would back down some and work up. More for pressure than anything else.

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    Member Smokey's Avatar
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    Kodiak,
    I have been playing with 2 diff 140 grain bullets in a 280 of late - it seems to like them near max - for the RL19 powder that's 57 grains - today I loaded a 3rd 140 bullet and dropped to 56.5 grains as that seems to be working well with the other 2 bullets and no pressure problems showing for them.
    I have tried 6 diff powders so far and the 2 that have gave me the smallest FPS variance were IMR 4831 - (17 fps ) and RL19 ( 43 fps ) - I am not going to suggest max loads are safe - however I think the manuals are pretty safe in the max they list and in a good modern firearm it does not scare me to change bullets ( of same weight ) and try a near max load that has been working SAFELY as a way to skip some trials. However like others have stated it seems to be hit or miss if it will perform the same way for sure....
    When asked what state I live in I say "The State of Confusion", better known as IL....

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