Can shooting long bullet give more bbl life

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Iron Worker, Aug 28, 2011.

  1. Iron Worker

    Iron Worker Well-Known Member

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    Waiting on a 28" 8" Brux 6mm bbl. It will be chambered in 6x284 . If I only shoot 105-115gr bullets will I get better bbl life then shooting faster lighter bullets ?
     
  2. Mikecr

    Mikecr Well-Known Member

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    I doubt it.
    Faster/hotter powders expose the bore to heat for less time, but it's more peak heat.
    Slower/cooler powders expose the bore to less peak heat, but for a longer duration.
    This I believe, is why powder AMOUNT to a given bore ID is dominant in barrel life.

    You just can't wiggle things much beyond this, and no matter what you do a 6x284 will burn up with a low shot count.
    The best you can do is allow the bore to cool between shots. NO HOT GROUP SHOOTING.
    Assuming it's for hunting, I would focus on cold bore accuracy.
     

  3. shortgrass

    shortgrass Well-Known Member

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    Bullets with a longer bearing surface (the area that actually engages the rifling), like target bullets, will wear a barrel quicker.
     
  4. Broz

    Broz Well-Known Member

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    Larger bullets usually require a lesser load of powder to get to the max pressure of a given caliber. Having owned 6mm/284's before I feel that lesser powder will be your friend. The 6mm/284 like most wildcats will burn the throat long before any rifling wear will come farther down the tube. Mikecr gave you good advice here. Take time to cool between shots. Shoot hot groups or take it to a dog town and start repeated firings and you are probably looking at a 500 round rifle, or less. Hunt with it and wait between shots and you will get the longest life. The heat from this large case and the relativly small bore is the killer.

    Neat chambering though they tend to be very accurate.

    Jeff
     
  5. Iron Worker

    Iron Worker Well-Known Member

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    I've been told that Ramshot Magnum powder will give greater life then stick powder ? Any truth to that ?
     
  6. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Iron worker,

    exactly the other way around; heavier bullets wash out a barrel notably faster than lighter ones do. Those long, heavy bullets give better performance at distance, but thqat's the price we pay for that improvement. They're particularly hard on the throat area, as it takes longer to get these bullets moving down the bore than it does a lighter one. In the meantime, all that pressure and high temp flame has more time to do its damage to this area before the bullet gets "out of the way." The rest of the barrle will be in good shape, but the throat will soon be cracked and worn for a short distance ahead of the case mouth.
     
  7. Iron Worker

    Iron Worker Well-Known Member

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    I'll for sure allow for bbl cooling . Any bore treatments out there of any merit ? There's a shooter on 6mmbr that has same caliber and bbl. He say's "He has spoken to some one on the Sierra bullets staff that claims 3,000 rnds out of a 6x284 shooting heavy bullets using Ramshot Magnum powder"
     
  8. Kevin Thomas

    Kevin Thomas Well-Known Member

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    The 3,000 round figure for this combo is right in line with the Easter Bunny, Santa Claus and an honest poliotician; a figment of someone's imagination. unless you're calling a two or three MOA barrel still viable, no, it'll be gone long before you get anywhere near that figure. I'd call it 1,000 rounds or thereabouts before losing the .5 MOA mark. Where you call a barrel "done" is up to the individual shooter, but there will be a noticable degradation in accuracy and a drastic increase in flyers by this point.

    As the Ramshot, double based powders generally run higher flame temps than do single based propellants. This can equate to shorter barrel life in some cases, and in others there doesn't seem to be much difference. All depends on the individual comparison. All other things considered, you won't see as much difference in barrel life caused by powders as you will between those caused by bullet weight and other factors.
     
  9. Iron Worker

    Iron Worker Well-Known Member

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    I kind of figured that was some hooey ! While waiting for this bbl I'm re-thinking having it chambered for 6x284. How much better bbl life with 243 AI ?
     
  10. Outlaw6.0

    Outlaw6.0 Well-Known Member

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    ^^^^ Now that made me laugh, thanks Kevin, & I fully agree, minute of watermellon is probably all that's going to be left after 3k rounds... I AM using Magnum (as well as other shooters), it is a wonderful powder for the 6-284, I recall my load testing from 54.5 up to 56.5 grains (5 loads) all grouping under .500 at 100 yds, thats pretty consistant in my book, in fact the last two 56.0 & 56.5 both going sub .300. As far as bbl life goes... honestly, they are a consumable item.... kinda comes with the territory.
     
  11. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Iron worker,

    Fairly simple set of tradeoffs here, and we have to start with the realization that there is no perfect cartrdige. They're all a seeries of tradeoffs, and we each have to decide where we want to put the priorities. Long barrel life means reduced performance in terms of velocity and and energy, higher levels of performance means you sacrifice some longevity. A 22 Long Rifle is easily the most efficient 22 caliber cartridge, while the 22-250 or 220 Swift are the least. Now if we want to whack a groundhog at 450+, which is the most effective? Efficiency and effectivness are not the same.

    The 243AI would/should give better barrel life than a 6/284, but again it comes down to what you're using through it. I wouldn't expect to see much more than 1,500 rounds or so with this one, if we're still talking about the same weight bullets. Pick the level of performance you want, and then just accept the fact that as Outlaw says, barrels are perishable tooling.
     
  12. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Outlaw,

    I know a grand total of one guy at Sierra that I know has ever worked with a 6/284, and I seriously doubt he's ever worn out a barrel. Hey, I know what you mean. Barrels are threaded on at least one end, kind like they were meant to be replaced from time to time!

    Can't get too worked up about the barrel heating issue, either. Had one of my 308s pretty damned hot four different times this past Sunday. Mid range match at St Louis Bench Rest club. Each of the four matches consisted of 22 shots in not more than 22 minutes, and I usually try to wrap it up in less that 10 to get away from too many wind changes. Clear blue sky, bright sunlight and very high temps all combined with the shooting to make the barrel waaaay too hot to touch. Only way to get around that one is to build it, put it in the safe and leave it there. Otherwise, it's gonna get hot from time to time. Oh well. Not the first barrel I've had on that particular action and it sure won't be the last.
     
  13. Iron Worker

    Iron Worker Well-Known Member

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    Got it. I already have the dies ,so 6x284 lives. Hey Outlaw what kind of velocities were you getting with those charges you listed ?
     
  14. Outlaw6.0

    Outlaw6.0 Well-Known Member

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    You would have to ask me that!! I do know that at 54.5 you're looking at a measly 3150 (got to start somewhere), I cannot remember for some reason where the velocity is at 56.5 (Hey, it's Monday) i'll try to get that to you.

    Kevin,

    You're correct, not the first bbl for me either, next one will be 6-284 also... horse power is addicting! not what a fella would want in a tactical match for sure, but man 'o' man are they flat shootin..gun)