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Thread: unstable bullets ?

  1. #1
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    unstable bullets ?

    i got a 13.5/1 twist barrel that shoots sub 0.100 " groups indoor 100y all day long with BT 68 gr bullets and with loads of 29 gr to 30 gr N133 .
    but when i take it outside it shoots like crap a little change in wind variations make it shoot big groups (.500/.750)
    is the 68 gr boat tail (.825" jackets) maybe not stable in that twist ? ore is it just a not so good barrel ?

  2. #2
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    Quote Originally Posted by johan teughels View Post
    i got a 13.5/1 twist barrel that shoots sub 0.100 " groups indoor 100y all day long with BT 68 gr bullets and with loads of 29 gr to 30 gr N133 .
    but when i take it outside it shoots like crap a little change in wind variations make it shoot big groups (.500/.750)
    is the 68 gr boat tail (.825" jackets) maybe not stable in that twist ? ore is it just a not so good barrel ?
    Are you using good wind flags? And, are you aware of just how much a 10 mph wind can move a bullet at 100 yards?


    .

  3. #3
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    If it shoots sub-1's all day long inside, there's nothing wrong with the barrel or bullet. If either were bad, you wouldn't get those results....which are unbelievable.

    -Lee
    www.singleactions.com

  4. #4
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    There are those that believe otherwise. I'm not here to argue with them
    From my experience your tune will have to change with the condition
    A light seating depth may shoot great in powder puff no wind conditions and won't touch two together when the wind blows.
    You will have to work up the outdoor tune it won't be the same
    As well as what Jerry says about flags

  5. #5
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    Tim - I agree completely with respect to tuning to the conditions. Indoor vs. outdoor is a big shift, and not just on wind. I was just saying if he can tune it to always shoot sub-1's indoors, the bullets and barrel can't be all that bad.

    -Lee
    www.singleactions.com

  6. #6
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    How have you shot with other barrels outside? I can understand if you are shooting powder puff loads inside and then they aren't shooting outside in the wind, but with the loads that you are shooting, they certainly aren't powder puff loads. I've never seen a barrel that shoots so well in no conditions to light conditions that shoots so poorly in windy conditions. I'm sure you are using flags as I've seen your name on this forum for a long time and recognize you as a benchrest competitor. Typically what I'll see and more so at 200 when I'm missing a wind condition is that I'll have 3 or 4 clustered in a small group and one of the shots out. Whether this is the popping a shot from the load not being tuned, I don't know or whether it's missing a condition. I've always considered it missing a condition change as it seems in Texas matches we get anything but stable winds with wildly varying intensities while we're shooting the group. I've found the better I pay attention to the flags for each shot, the better I shoot. I'm sure that you have other barrels for this rifle. I'd give them a try and see how they do inside and outside.

  7. #7
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    i got my shares of wins in the past years normaly i end up in the upper portion of the participans ore better over here in the frenchy region
    i got my own windflags had some barrels that shot better then other in the wind but thise one give me so big groeps (2-3 times bigger then what to expect ore when i compaire to the other shooters)
    so bad i even changed out my scoop to see if that was the problem
    i got a 180 mls drive to the nearest 200m range from my place so do not go every week ( the indoor range is only 5 mls) i work up a desent load inside that in my opinion can work ouside (29.3/30 gr N133 ) (thise barrel shoots well inside with 29 and 30 gr loads)
    both give the same to big results outside i will try some FB to see if they shoot better in the wind ( barrel got 700 shots now so it probly is gooing to be scrapped soon but i got 4 other ones with the same twist 13.5
    and about 8000 BT bullets .so i hope it is not the combination of 13.5 and the 68 gr BT bullets otherways the bullets will gatter some dust for a few years lol

  8. #8
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    Quote Originally Posted by johan teughels View Post
    i got my shares of wins in the past years normaly i end up in the upper portion of the participans ore better over here in the frenchy region
    i got my own windflags had some barrels that shot better then other in the wind but thise one give me so big groeps (2-3 times bigger then what to expect ore when i compaire to the other shooters)
    so bad i even changed out my scoop to see if that was the problem
    i got a 180 mls drive to the nearest 200m range from my place so do not go every week ( the indoor range is only 5 mls) i work up a desent load inside that in my opinion can work ouside (29.3/30 gr N133 ) (thise barrel shoots well inside with 29 and 30 gr loads)
    both give the same to big results outside i will try some FB to see if they shoot better in the wind ( barrel got 700 shots now so it probly is gooing to be scrapped soon but i got 4 other ones with the same twist 13.5
    and about 8000 BT bullets .so i hope it is not the combination of 13.5 and the 68 gr BT bullets otherways the bullets will gatter some dust for a few years lol
    I'd think that the bullets shooting well inside pretty well shows that they will shoot. I've shot lots of 13.5 twist barrels and 68 gr BT's with good results. I think you are on the right track though in trying flat base bullets in the barrel. If you can't get the BT's to shoot, then I'd try flat bases before giving up on the barrel. If the barrel just won't shoot in the wind, I wouldn't waste too much time on it and move on to another barrel. There's too much money involved in this sport with shooting costs to waste too much time on a barrel that won't shoot. Strange though that it will shoot inside with normal loads and won't outside with those loads or minor variations from those loads. It could be that you have it tuned to be wind sensitive and going up or down on the load a little might take care of that. (Benchrest shooter's always go up, never down. ) A little more jam might help as well. I've seen that make a difference as well.

  9. #9
    Join Date
    Feb 2003
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    I shoot indoors a lot . I shoot mostly all 13 1/2 or 13 gain tw
    It's the Load it's not the bullet . This happens a lot . Usually that load is not too far off.
    On the outside just start shooting 2 shot groups.
    Start with the low load and work up then pick the good groups and go to three shots .
    Then go from there .

  10. #10
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    Hi Johan, long time no see. Johan has shot at the Supershoot several times. We have solved some of Belgium's and the USA's problems over a drink at the Legacy a few times.

    Later
    Dave

  11. #11
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    Quote Originally Posted by Dave Coots View Post
    Hi Johan, long time no see. Johan has shot at the Supershoot several times. We have solved some of Belgium's and the USA's problems over a drink at the Legacy a few times.

    Later
    Dave
    yes a lot of problems where soved with the bourbon on the porch ofthe legacy inn LOL

  12. #12
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    Quote Originally Posted by Lou Murdica View Post
    I shoot indoors a lot . I shoot mostly all 13 1/2 or 13 gain tw
    It's the Load it's not the bullet . This happens a lot . Usually that load is not too far off.
    On the outside just start shooting 2 shot groups.
    Start with the low load and work up then pick the good groups and go to three shots .
    Then go from there .
    thx for the tips

    :it can be a powder issue also problems ocurred , around the same time i opened a new batch of N133 looked on the heavy side i can get 30.5 gr in the case rather easy (56.5 clicks)
    i need to meassure the speed (somthing i so often forget to do ) my usual max tune is when the bold starts clicking i decrease the load

    i need to take more notes when i change stuff that will make my benchrest life a lot easyer lol

  13. #13
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    Quote Originally Posted by johan teughels View Post
    thx for the tips

    :it can be a powder issue also problems ocurred , around the same time i opened a new batch of N133 looked on the heavy side i can get 30.5 gr in the case rather easy (56.5 clicks)
    i need to meassure the speed (somthing i so often forget to do ) my usual max tune is when the bold starts clicking i decrease the load

    i need to take more notes when i change stuff that will make my benchrest life a lot easyer lol
    My problem is trying to remember to remember to take notes.....

  14. #14
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    Quote Originally Posted by zippy06 View Post
    My problem is trying to remember to remember to take notes.....
    My problem is trying to find the notes that I did take.

  15. #15
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    It's stable

    I normally shoot a 30 caliber, but I'm no stranger to the PPC. Before the 13.5" twist became popular, most 6PPC shooters used a 14" twist. At that time, the majority of shooters were also shooting button rifled barrels. Some of them came out with twist rates that were slower than 14" twist, becuase button rifling is not as accurate on twist rates as the modern cut rifled barrels. I was one of those who shot a 6PPC with a Hart 14" twist button rifled barrel. I also shot 68gr Tucker boat tails, and even had decent results with the Sierra 70gr Matchking. I shot at an elevation of 1100ft in central Texas. I never had stability issues. Also keep in mind that about 1 out of 4 of all PPC shooters still prefer a 14" twist. Because of high altitude shooting (6500ft Raton), Speedy actually shoots .825" jackets out of a 15" twist.

    As for stability factors, most benchrest barrel and bullet combinations only yield a stability factor between 1.1 and 1.3, and while a 1.5 is the recommended stability factor, that high of stability factor rarely achieves optimum accuracy. A stability factor of 1 is considered stable. I calculated your stability factor at 1.2, or right in the middle of the normal range for benchrest combinations.

    As everyone else stated above. The problem lies elsewhere.

    Michael

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