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  1. #31
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    Default Re: Bullet Jump and its affect regarding Accuracy

    Shooty, I can believe in 0.075 mm measurements in regard to concentricity and even more so for chamber fit of case, but for OLL (overall loaded length) --- naaaaaaaaaaaa!
    I guess it would be possible these days with regard to using Mono bullets that are manufactured to 0.005 mm, but then you going to have to shoot from a chamber thats the same temperature every shot as well.

  2. #32

    Default Re: Bullet Jump and its affect regarding Accuracy

    @Treeman, good point about barrel expansion. It probably also the reason why he backs out of the lands. So that you don’t also have expansion issues between first and more shots, as well as OAL variation


    Sent from my iPad using Tapatalk

  3. #33
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    Default Re: Bullet Jump and its affect regarding Accuracy

    Quote Originally Posted by janfred View Post
    Not sure what shooting ranges are like where you are from with regards to safety, but at all the ones I have been to, you have to open and make safe when a ceasefire is called. There is no latitude to quickly fire the shot, unless you want to be disqualified and instructed to leave.

    Also, I think it is stupid not to be able to open the bolt on a live round.
    Look, this was many years ago, in an environment where things were generally... accommodating... to the toppies that participated. Not condoning any of this, just relaying, with the intention to illustrate that loading onto the lands were not necessarily the purpose, but the result of what these guys were trying to achieve.

    The (unfortunate) effect, partly resulting from this, was that was that trying to get on the lands became a "thing" for "normal" shooters and hunters, "because jislaaik the Bisley guys shoot out to 900m and they do it so it must be good", WITHOUT a full understanding of the original reasons.

    Whilst looking for something complete different (although my tinfoil hat tells me this isn't coincidental, and that Google is reading our forums posts), I stumbled on an interesting link:

    https://precisionrifleblog.com/2020/...est-practices/

    The follow up artcles are actually of more interest to me, because it explains that there also seem to be a range of "jump distances" where the POI is insensitive to the specific value of the jump:

    https://precisionrifleblog.com/2020/...d-development/

    and

    https://precisionrifleblog.com/2020/...elopment-data/

    The above are probably more applicable to high-volume, long distance shooters, but makes interesting reading nonetheless.

    Coming back to the original question, I'm quite sure it's possible in most well-made rifles to develop a ~1MOA load for most of the bullets it can shoot to hunting distances, without bothering about jump (i.e by powder charge alone, and loading to whatever OAL guide you prefer, be it a certain neck engagement, magazine length, cannelure position, etc). Perhaps one can shrink this even further by playing atound with the jump, but I also think you may end up with a solution that may be sensitive to the specific jump, and that the effort expended may not be warranted for most situations.

  4. #34
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    Default Re: Bullet Jump and its affect regarding Accuracy

    Thanks Pirate. Interesting reading and backing up ECortana's 3thou increments, although 5thou seems common.
    Did not think it was that sensitive.

    Sent from my SM-A505F using Tapatalk

  5. #35
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    Default Re: Bullet Jump and its affect regarding Accuracy

    Quote Originally Posted by Smurf View Post
    Thanks Pirate. Interesting reading and backing up ECortana's 3thou increments, although 5thou seems common.
    Did not think it was that sensitive.

    Sent from my SM-A505F using Tapatalk
    ************************************

    Will take a long nite to convince me that it is. I know in theory it can be, but then you will need to tell me about the temperature controlled room you shooting in and CNC turned bullets and CASE'S and other variables to much to list.
    Go read this and then consider, one of my favorite go back to again and again bit of shooting writing:
    https://precisionrifleblog.com/2013/...ifle-accuracy/

  6. #36
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    Default Re: Bullet Jump and its affect regarding Accuracy

    Thanks Dave.
    Undoubtedly these BR shooters operate in a different universe.
    I cannot see jump increments of 0.1 mm making a difference in my setup, but sweet spots clearly exist and is supposedly only about 1.2 mm wide.
    At 0.1 mm increments you would need perfectly sorted cases by volume and likewise bullets measured Base-to-Ogive and perfectly sorted. Else the volume error will be bigger than the seating volume change.
    What I have learned though is changing jump by 0.3 mm is too much when searching for a sweet spot range.

    Sent from my SM-A505F using Tapatalk

  7. #37
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    Default Re: Bullet Jump and its affect regarding Accuracy

    .5 mm increments works for me, but then I am usually only chasing clover leave representations at 100 m

    To be fair, perhaps the likes of me should not argue too much with the guys that shoot 3 shot 1 holes at 200 m and hit the target at 1000 m
    That said i doubt there are 10 guys on this site that can/have the equipment and ability to show on paper what can be achieved by most of this 0.00? fuss.

    I may likely get flack now ...................................but then again perhaps thats the idea.

  8. #38
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    Default Re: Bullet Jump and its affect regarding Accuracy

    Quote Originally Posted by treeman View Post
    ...

    I may likely get flack now ...................................but then again perhaps thats the idea.
    To draw FLAK, you first have to FLY.

  9. #39
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    Default Re: Bullet Jump and its affect regarding Accuracy

    .................................................. .................................................. ...............
    censored. Much.

    now we can never hunt in the same Province.

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