Big 7 vs Big 30 --- long range rifle cartridge selection

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Len Backus, Nov 28, 2011.

  1. Len Backus

    Len Backus Administrator Staff Member

    Messages:
    6,359
    Joined:
    May 2, 2001
    I have a new rifle customer asking my opinion of what cartridge he should select from those I offer. I mentioned to him how I had surveyed my LRH members in a POLL for their opinion of favorite long range hunting cartridges. He indicated some interest in the 300 RUM and based on how he describes his needs I said either the 300 RUM or the 7 Dakota would serve him well.

    cartridges-navigation.jpg

    He asked me how the Dakota compares to the 300 RUM. I explained that I have been a proponent of the 7mm bullet caliber since Warren Page wrote about Remington's introduction of the 7mm RM in the 1962. My first bolt action rifle was in this cartridge a year or 2 later. I knew next to nothing about ballistics but simply reading the drop table and velocities told me the skinnier bullet retained velocity better than the 30-06 and had less drop as a result.

    Anyway, the following is what I told Bryan in an email this morning.


    Bryan

    In order to select a cartridge for your new Long Range Rifles, LLC gun you asked me for a comparison of the ballistics between the 7 Dakota and the 300 RUM. Both are great cartridges and will do a fine job for your needs.

    There are 4 images attached that show the velocity, wind drift, drop in minutes of angle, and energy.

    The 300 RUM uses about 20 grains more powder for the 210 grain Berger vs the 180 grain Berger for the 7 Dakota. I used the 210 for the RUM comparison since that would perform the best at 1,000 yards over a lighter 30 caliber bullet.

    I used an Excel spreadsheet that I developed to compare recoil. Recoil will be about 50% greater with the 300 RUM than with the 7 Dakota since the rifles weigh the same but the RUM has more powder, heavier bullet and same initial velocity.

    So for 50% more recoil with the 300 RUM you get roughly the same ballistic performance except for higher energy with the 300 RUM -- which is so high with both cartridges that the difference in energy is academic.

    Len

    VELOCITY
    7Dvs300RUM-veloc.jpg
    .
    DROP
    7Dvs300RUM-drop-moa.jpg
    .
    WIND
    7Dvs300RUM-wind-drift.jpg
    .
    ENERGY
    7Dvs300RUM-energy.jpg
     
  2. pyroducksx3

    pyroducksx3 Well-Known Member

    Messages:
    782
    Joined:
    Sep 27, 2009
    Using bulletflight fte I get a little higher energy numbers but very similar. I myself am struggling with this same decision. I went with a 7 rem mag in the end. The smith I'm using states I'll get around 3100 to 3150+ using 168 bergers in a 26" barrel. I have yet to prove to myself that that I can shoot out past 800 yards, which is where the 300 starts to matter on elk size game. After all the thinking I went with the 7 because after all the practice I will be less beat up. About the time I get truely competent out too 800+ the barrel will be running low on life. I figure then only after I have proved to myself that I need and can shoot out to a 1000 I will rebarrel to 300 RUM. The other thread I started dealing with this exact question is 300 RUM using 210/230 Berger vs a 7mm using 180 bergers going 3100 fps. The polls support the 300 but its closer than I thought if would be.
     

  3. rscott5028

    rscott5028 Well-Known Member

    Messages:
    2,608
    Joined:
    Apr 18, 2010
    I've never seen 7 Dakota ammo on the shelf at Walmart, Academy, or Cabelas.

    I hand load, but it's nice to have the option of factory ammo in a pinch.

    Is 300 RUM really 50% more recoil after installing a good brake?

    I put a CSR brake on my 300WM and it went from painful to pleasant.

    -- richard
     
  4. Len Backus

    Len Backus Administrator Staff Member

    Messages:
    6,359
    Joined:
    May 2, 2001
    Richard, where I hunt 90% of the time I couldn't find any of the typical long range factory cartridges. And if I found some 300 RUM's to use that one as an example I wouldn't have much of a hunt anyway. Not sighted in, no good groups, no drop table.

    So I've always thought that concern was overblown.

    If you put a brake on BOTH rifles the recoil will still be 50% more.
     
  5. pyroducksx3

    pyroducksx3 Well-Known Member

    Messages:
    782
    Joined:
    Sep 27, 2009
     
  6. Franklin

    Franklin Well-Known Member

    Messages:
    252
    Joined:
    Feb 23, 2008
    Len,

    Your post gives us a good, head to head comparison, but what are you asking us to reply about?
     
  7. Len Backus

    Len Backus Administrator Staff Member

    Messages:
    6,359
    Joined:
    May 2, 2001
    Just meant to be informational, no need to reply.
     
  8. theflyonthewall

    theflyonthewall Well-Known Member

    Messages:
    224
    Joined:
    Jul 10, 2011
    .......My interpretation of what Len is asking is the membership's opinion on a caliber choice and WHY.

    My response to that is this:

    Not knowing how proficient this shooter is, I'd go with the Dakota hands down just for the recoil issue. Those of us that have put lots of lead downrange and take our shooting to the extremes tend to be able to shrug off the psychological effects of recoil pretty well. I know I'm preaching to the choir to say the least, but the point is still valid when a new shooter is asking about big calibers.

    I'd never recommend a RUM to someone that I didn't know PERSONALLY, so I could gauge whether they could handle it well.

    I've seen tons of posts about shooters getting beat up shooting the 7mm Rem Mag. I can't fathom that myself. But it goes to show how recoil sensitive some shooters are.

    So yeah...if it were me, I'd have to recommend the Dakota.
     
  9. rscott5028

    rscott5028 Well-Known Member

    Messages:
    2,608
    Joined:
    Apr 18, 2010
    Overblown or not, that's my opinion/preference.

    If you had to go to all that trouble to do the comparison, then the Dakota isn't compelling for me and I'd lean towards the one with a factory ammo option.

    But, I do agree that accuracy and long range viablility would be a big concern if you had to resort to that. So, the spare rifle is always a good thing as stated by pyro.

    Thanks,
    Richard
     
  10. pyroducksx3

    pyroducksx3 Well-Known Member

    Messages:
    782
    Joined:
    Sep 27, 2009
    I do however agree with you to a point on factory chamberings. In the case of the Dakota what would concern me is the brass availability. And from what I have heard the Dakota brass (made by hornady I believe) has gotten mixed reviews. I have heard that it's expensive though. At least with Remington brass it's cheap and you can get it.
     
  11. ultraedge

    ultraedge Well-Known Member

    Messages:
    410
    Joined:
    Aug 17, 2011
    I hunt with both 7STW and 300 RUM. Both are very accurate but the 7STW does not hit as hard or deliver as much damage as the 300 RUM
     
  12. B23

    B23 Well-Known Member

    Messages:
    1,106
    Joined:
    Oct 30, 2008
    Before I became a big fan of customs and wildcat chamberings I had a small love affair with Weatherby's. I owned a 7mm Wby Mag for a long time and shot alot of game with it before I sold it and bought the first Accumark 300Wby mag. my local dealer got in his store.

    I would assume there was a measurable difference in recoil between the two but I noticed little to no difference in recoil between them. Having used both for many years I would go with a big .30 over a big 7 any day. Im a big fan of the big .30's such as the RUM and IMO if I could only have one rifle to do everything with, it would be a big .30 such as the RUM.
     
  13. elkaholic

    elkaholic Well-Known Member

    Messages:
    5,346
    Joined:
    Dec 4, 2008
    Unless recoil is the issue, I would always go with the 300 when you are talking long range. This is of course comparing equal or close b.c.'s. All else being equal, there is no substitute for the extra punch and greater frontal area so why not take advantage of it. This is why a lot of the guys on this forum use the big .338's........Rich
     
  14. pyroducksx3

    pyroducksx3 Well-Known Member

    Messages:
    782
    Joined:
    Sep 27, 2009
    I think we get lost and focus just on ft/lbs energy when we talk about which calibers when really there's so many other factors to consider as well. The big 338's I personally don't even consider an option unless you are planning on shooting over 1000 yards. Do these other calibers arrive with more energy? Yes! But do you need it is the question. No doubt the big 30 have more power and therefore "more killing potential" but that doesn't mean that the lesser calibers are not effective. I think there was a poll on here and most shooters have never taken game past 700 yards, now j know there are lots that have but these are exceptional shooters and not the norm. My realistic range isn't to 1000 so shy would I need a gun that has better power at ranges I won't even be hunting, especially when there are option that fit my needs more appropriately. There's no doubt on pure numbers the n
    Big 30 have more killing potential than the 7's and the big 338's more than the 30's but there are always individual factors to consider that make make a lesser chambering a better choice. Don't get me wrong though I love the idea of a 300 RUM and one day it will be the right choice for me, it just isn't right now.