6.5-284 VS 260 Remington,

Discussion in 'Big Stuff -- 6.5mm, 7mm, 30 Cal' started by jonsidneyb, Mar 31, 2007.

  1. jonsidneyb

    jonsidneyb

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    When I look at the diagrams of these two cartridges. They seem very similar to me.

    I am still learning so I admit to alot of ignorance.

    I see the case head is the same. Did .260 Remington come along because the 6.5-284 is possible too long for some actions with long bullets?

    Why would one chose the 6.5-284 over the .260 and why would someone chose the .260 over the 6.5x284?

    Pros and Cons please :)
     
  2. jonsidneyb

    jonsidneyb

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    Duh,

    I see the difference. The 284 case has a rebated rim. The casing is indeed fatter.
     
  3. rcw3

    rcw3 Site $$ Sponsor

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    6.5x284 also longer with a steeper shoulder angle & a good bit bigger capacity too. 260 Rem will be working real hard to try to keep up with a 6.5 x284.

    Robert
     
  4. mysticplayer

    mysticplayer

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    From the perspective of LR shooting for accuracy/F class, the 139/142gr VLD bullets like to go around 2900 to 3000fps for best accuracy. This means the 284 case is bigger then necessary. The 260 case a bit smaller then desired however, gets very close depending on the barrel and pressures you run.

    So you need to decide on the application and rifle specs. If you are shooting a shorter barrel and/or for hunting, the 284 is the better case for LR shooting as you have the case capacity to replace the shorter barrel.

    If you are able to shoot a long barrel and concerned about barrel wear/heat/recoil, then the 260 might be the better choice. if you are doing a sport that requires mag feeding, the 260 would be my choice.

    I shoot F class and have settled on the 6.5 Mystic which is my version of the 260AI. I can almost reach 3000fps in my 30" match barrel but this is way overpressure and accuracy stinks. 2900 to 2950fps is where it thrives.

    At these speeds, I run 100% load density and a few grains less H4831SC then common loads in a 6.5-284 and a few grains more then in a 260R.

    260/308 brass is plentiful and way less money then Lapua,I shoot Win brass exclusively).

    Another to consider is the 6.5X55 Swede. Case volume is pretty much the same as the 6.5 Mystic/260AI so you have a case that can be used right out of the box without case forming.

    If you shoot closer more often then far, the smaller case might work best.

    No absolutes in this comparison. Just apply to the desired result.

    Jerry
     
  5. DogBuster

    DogBuster Site $$ Contributor

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    260 AI or std 260 for my LR p/dog needs...my AI has 8 twist...my 260 has 9 twist..both Pac Nor barrels...much better barrel life than the 284 case..
     
  6. Tcon260

    Tcon260 Site $$ Contributor

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    mysticplayer,

    What kind of barrel life are you getting out of your 260 Mystic?
     
  7. mysticplayer

    mysticplayer

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    Barrel one has seen 900+rds and has moved about 20thou. Barrel 2 has seen 400+rds and has not moved.

    They seem to be holding up very well.

    Jerry
     
  8. Kevin_Duckworth

    Kevin_Duckworth

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    Using a 260, a friend is getting 2930 fps with 44 grain of H4350,actually ADI 2209 but it's the same thing I understand) and MK142s, and claims very good 100yd groups,.3").

    This ain't that far from the velocities that most people seem to be driving their 6.5 x 284's,around 2950 fps) and with at least 6 grains less powder.

    Quickload shows a theoretical max chamber pressure of 61290 psi for the 260 with 44 gn of ADI 2209 giving 2944 fps, so he's doing a little worse than the theory suggests.

    By contrast Quickload suggests a 6.5 x 284 needs 51 gn of ADI 2209 at theoretical max chamber pressure of 51658psi to give 2956 fps.

    Given the claimed excellent barrel lifetimes of the 260, I wonder if it is worth another look?

    Kevin
     
  9. Your figures show almost 10,000 psi more pressure for the 260 loading. Load the 6.5-284 to the same pressure and then compare the ballistics.

    Barrel life is secondary to winning performance for the vast majority of competitors. The 6.5-284 serves best as a competition cartridge.
     
  10. Kevin_Duckworth

    Kevin_Duckworth

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    As you rightly say, increasing the pressure to similar levels increases the theroretical velocity to 3107 fps.

    But my point is that people don't seem to be using these velocities-repeatedly the "magic range" claimed is 2950-3000.

    Is a 6.5 x 284 therefore more "inherently accurate" than say a 260, and is that partly why people use it?

    And is the life of the 260 much shorter at these pressures, so the longevity goes away?

    For example there is a spreadsheet available on the net that calculates barrel life, and it indicates a "lifetime" of 1350 rounds for the 6.5 x 284 versus only 1550 for the 260 using the loads mentioned earlier-which would tend to indicate that indeed the 260 longevity may evaporate at these more aggressive loads.

    I'm not trying to raise a bunch of theoretical arguments which fly in the face of reality but seeking to understand what is it about the 6.5 x 284 that makes it the huge success it obviously is.

    And I'm good with the idea of barrels being a consumable, and a means to an end.

    Kevin
     
  11. Just my opinion based on personal experience but I believe that a .260 has to really strain to get the 139-142 grain bullets out at 2900+ fps, while the 6.5-284 does it easily.

    I've found that, generally speaking, most cartridges yield better accuracy when they're loaded to under maximum pressures. Also the additional 10k psi in the .260 can't be doing very much for case life.

    In my experience, 48.5gr of H4350 or 51.5gr of H4831sc both deliver velocities in the mid 2900 fps range with either the Scenars or the SMK's with ES's and SD's in the single digit range and fine accuracy from my 6.5-284 with its 30" Bartlein 5R 1/8.5 twist barrel. And I haven't thrown a case away yet :)

    Some shooters that I know with .260's keep talking about Ackley-izing them, but then they're looking at fireforming their brass and feeding troubles from a staggered magazine, not important unless you need a repeater, but fireforming's always been a PITA for me. Another thing about fireforming that bothers me is - where's the supposed advantage in barrel life when you've got to fire all of those extra shots just to form the brass that you're going to load?

    Then there's always the variable quality of .260 brass combined with its sometimes sketchy availability.

    OK, so it's obvious that I'm predjudiced towards the 6.5-284. Nobody's perfect :D
     

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