WHY (c3) do barrels with the same specs ‘prefer’ different ammo?

Discussion in '.22 Rifle/Rimfire Discussion' started by Vincine, Mar 31, 2013.

  1. Vincine

    Vincine New Member

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    Their rifling, twist rate, heat absorption, cool rate. etc. doesn't change. Their tolerances should not be different. Presumably the QC of high end ammo doesn't change.

    Finding the ‘right’ ammo for a specific rifle is such an accepted practice, I would've thought some investigation on this would have been done.

    It reminds me of when people thought it mattered whether they used ‘Shell’ or ‘Gulf’ in their cars.
     
  2. Axxe55

    Axxe55 The Apocalypse Is Coming.....

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    i like to think of rifle barrels as like fingerprints. every one of them is different. even if you took 10 rifles of the same make and same caliber, every one of them would group differently with the same ammo. each one will like a certain bullet weight or a certain ammo brand to be accurate.

    honestly, even though all were built exactly the same and on the same equipment, a person would think they would perform the same, but i can't tell you exactly why they don't.
     

  3. Vincine

    Vincine New Member

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    But, but, but, . . . looking through the barrels and looking at 22lr bullets, it's clear to me that the barrels are machined and the 22lr bullets are not (at least not the ones I can afford). There is more variation in the bullets than the barrels so shouldn't the barrels be more consistent and the ammo variable?

    Or is cold forging/hammering a hit or miss process?
     
    Last edited: Mar 31, 2013
  4. Axxe55

    Axxe55 The Apocalypse Is Coming.....

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    i see what you're saying and i agree, but honestly i don't have an explanation a to why. hopefully someone much more knowledgeable than me will chime in.
     
  5. Overkill0084

    Overkill0084 Active Member

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    You'd think so, wouldn't you?
    It's not just different brands of ammo. The variation from lot to lot of the same ammo can be dramatic. Some brands are more consistent than others, but variation seems inevitable. Production equipment wears, powder varies, different personnel overseeing the various processes. There are probably variables that would never occur to me. Variations amongst Match grade ammo was noticeable, even among high end makers. One lot of Eley Tenex can be noticeably worse than a great lot of CCI Green Tag. A weak lot of Green tag might not be any better than a good lot of Mini Mag. RWS Match seemed fairly consistent most of the time.
    I watched my Dad test multiple lots of ammo many times. It can be surprising sometimes. Like other consumer products, sometimes even the best names kick rubbish out the door. I always liked it when CCI would perform better than the expensive Euro ammo.
    Barrel making is subject to a huge number of variables as well. Quality of the steel. Content of the steel. Type of tooling used to make the barrel. Method used to create the rifling. The amount of wear on the tooling. The skill of the guy operating the tooling. The fit of the barrel into the action. The bedding of the action. And so forth.
    Combine that two sets of variables, add the shooter's variables and the weather, barometric pressure, temperature. You see where this is going...
     
    Last edited: Mar 31, 2013
  6. Vincine

    Vincine New Member

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    Okay, this is getting to it. But it makes my point. Being off by a hundredth of an inch, or thousandth of a psi, or whatever, on a rifle is a much lower variation than the same variation on a 22lr round and that different lots of 22lr, and even different rounds of the same lot, are more variable than different barrels. So that to say a rifle 'likes' Elmer Fudd brand ammo in their wabbit wifle the best is naive.
     
  7. Hawg

    Hawg Active Member

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    You have to take into consideration the differences in each raw barrel blank. Plus every time you pull a rifling button through a barrel it wears a little, giving each barrel its own characteristics.
     
  8. Overkill0084

    Overkill0084 Active Member

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    Yes & no.
    In my experience, Remington golden bullets have never grouped as well in my rifle (Kimber 82) as CCI Mini Mags. One can argue the reason, but at the end of the day, group size removes all doubt. The difference may be minor (it usually is), but it is there. Thus because of that, I will tell anyone who asks "My Kimber prefers CCI ammo." I shot Silhouette matches with Mini Mags because doubling or tripling the ammo cost for an extra 1/4" +/- at 100 yards wasn't worth it to me. My rifle shoots Eley products really well too, just not two to three times as well.
    In all honesty, it does eventually boil down to hairsplitting (or would that be hare-splitting ;) ) at some point. How much money & time is one willing to invest to milk that last bit out of his/her equipment?
     
  9. Hawg

    Hawg Active Member

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    Remington rimfire ammo is crap.
     
  10. 7point62

    7point62 Lifetime Supporting Member Lifetime Supporter

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    I'll drink to that.
     
  11. Tackleberry1

    Tackleberry1 New Member

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    No... It's not naive. Elmers rabbit rifle WILL like a particular ammo... but it won't like it forever. How's that for another wrinkle. Not only do we get to deal with finding the right match. We must also recognize that once found... barrel wear with each round fired means it will only go downhill from there. :D

    The best term I've found to explain ^^THIS^^ is "harmonics".

    Stick you index finger straight out... Now rotate it as though your drawing a small circle in the air. This is what your barrel is doing while each round travels down it's length. Accuracy is factor of consistently getting your round to exit the barrel at the exact same point of rotation.

    ^^THIS^^ is why many match grade bench rifles sport "heavy" barrels. While a barrels rifling is emparting "spin" on the projectile, the projectile "and the force of gas pressure behind it" are imparting torque on the barrel causing this rotation and heavier barrels rotate less than light weight barrels.

    It's also why serious centerfire competitors use handloads and why rim fire competitors individually weigh each cartridge. Consistency of load determines consistant "rotational" point of exit.

    As to why different barrels from the same builder and model prefer different loads, this is a factor of tooling and raw materials. Each time a barrel is "cut" the act of cutting imparts a degree of wear on the tooling, which means no two barrels are ever the same... and different "runs" may come from different batches of steel which effects "harmonics" and the resulting effects of "rotation" and "point of exit.

    Tack
     
    Last edited: Mar 31, 2013
  12. shouldazagged

    shouldazagged New Member

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    And we haven't even touched on the metaphsyical and genetic aspects...
     
  13. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    There are a number of "Intangibles" that cannot be accounted for. "Why" one brand, or weight, or velocity, or powder, or etc, works and another does not? Your guess is as good as mine.
     
  14. SSGN_Doc

    SSGN_Doc Well-Known Member

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    Stress points in the metal as the bore in made, then rifled. Then stress relieving the barrel. Also each barrel bore may not be cut with the exact same tools on each line. The tools do wear which causes other variations. A lot of the final trying is actually done by hand. Then rimfires, especially semi autos, rely a lot on rim thickness and chamber rim dimensions for consistent accuracy. So bolt face and extractor cuts play into it.

    I found I got best accuracy by measuring ammo for rim thickness and brands that had similar rim thicknesses performed similarly. So finding a rim thickness that a .22 likes seemed pretty important to accuracy.
     
  15. Axxe55

    Axxe55 The Apocalypse Is Coming.....

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    they also make a measuring device for checking rim thickness on rimfire ammo for consitency.
     
  16. mrrabbit

    mrrabbit New Member

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    You have to remember:

    A measurement is an estimate.

    Estimates have ranges no matter how fine your resolution is.

    Even with the finest resolution is production - one piece will differ from another - at a very small amount.

    Just like a 1.00 meter piece of 12g copper might will resonate differently than a 1.01 meter piece of 12g copper wire with a frequency range shift in the 10ths of Hertz.

    Perhaps one barrel is longer than the other by .01mm. Perhaps one barrel's rifling start left in chamber and end right on end, while the other starts up in chamber and ends down at the end. Perhaps the diameter of one barrel is .2201 while the other is .2202 allowing a little more premature gas escape. Perhaps the first barrel's rifling was done with a fresh "bit" while the second barrel's rifling was done with a "bit" that had already done 20 or 30 barrels resulting in rifling that is .001 in. less in depth.

    When your teacher in college give you a 97% on a chapter exam. That's not your real score. You real "estimate" was likely 97% with a SEM of +/- 2.5 with an alpha coefficient of .97.

    That means on a good day you might have gotten 99.5% and a bad day 94.5%. In either case, the score would have been considered a reliable statement about the test itself and your performance.

    All you can do is observe the behavior - and adjust to it.

    =:cool:
     
  17. stratrider

    stratrider New Member

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    As .22 LR ammo is so hard to find in southern Alabama I ordered what I could find online. I bought 1,000 rds of this fancy match grade German stuff, figuring most of what comes out of that country is of good quality. It was Randfeuerpatronen Kal .22 made by SK
    I used this in my new Ruger Single Six Convertible. It shot like a pig trying ballet for the first time. I "borrowed" some of my brother's el cheapo and very old CCI ammo and my groups really tightened up. Later, I tried the uber German rounds in my Henry Golden Boy and they really shined. Go figure.
     
  18. Trez

    Trez Well-Known Member

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    Am I the only person on earth that likes these??!!
    Whats the big problem with them? Im starting to think its your guys crappy guns not the ammo... :p

    The Golden Rems are what both of my .22 like best..
    My .22's are ancient too, one is a Winchester from 1933 and the other is a 1964 Weatherby

    :confused:
     
  19. natman

    natman Member

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    There is a certain amount of variation from one barrel to the next, even in ones that came off the assembly line one after the other.

    The major reason for different rifles preferring different ammo is barrel harmonics. When a rifle is fired, the muzzle vibrates back and forth, not a lot but enough to influence where the bullet lands 100 yards away.

    Ammunition that has the bullet exiting the muzzle just as it's changing direction (i.e. standing still for an instant while it does it) will be more accurate than than ammunition that has the bullet exiting while the muzzle is still moving.

    Since how the barrel vibrates is dependent on how the gun is bedded, there is plenty of room for variation between to seemingly identical rifles.
     
  20. longunner

    longunner New Member

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    I like em too they shoot out of my marlin great