LR Advantage - 7mm VS 30 Cal > Using the SAME CASE with caliber

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by 300magman, May 1, 2011.

  1. 300magman

    300magman Well-Known Member

    Apr 29, 2010
    If I were using the same case necked to either 30cal or 7mm (300 JAZZ vs 284 JAZZ) and looking for a hunting round to kill big white tail or even large caribou out to 1000 yards; which of the two would give me the best chances of a hit while still retaining lethal power.

    Now by "chances of a hit" I mean this, even a big magnum with a high BC bullet is dropping a foot for every 25 yards traveled....having a flatter trajectory helps compensate, to some degree, for those times when the range finder is off by a few yards. (maybe you can't get a reading on the deer, but you can get a reading on the big rock that he's walking in front of...but is he 5 yards in front of it or 10?)

    Also, wind..wind..and WIND. A 2mph full value wind can mean 12 inchs of drift, but a higher BC bullet and/or faster velocity could reduce that misjudgement to 10" (those extra 2" might mean the difference between a lethal hit and a wounding hit)

    I am just having a very hard time determining which caliber is superior when using the same case, I can calculate the drift and drop for various bullets. But its a game of guessing velocities. > > > a 180gr 30cal bullet will come out of the barrel faster than a 180gr 7mm bullet, but how much velocity difference will there be?
    And that is a simple comparison, it gets even harder to judge when comparing drift & drop of 160gr 7mm to a 200gr 30cal.

    And then there is the issue of terminal performance and bullet availability. Is it better to reach out with a 162gr A-max (7mm) that will impact with a few hundred fps more velocity but a few hundred ftlbs less energy than a 208gr A-max or is the advantage the other way around?
    And when you get into larger game, there is the 200gr Accubond with an SD of 301 and a BC of .588 ... but what does the 7mm have to compare to this? (bergers and a-maxs are much softer..correct?) and the 7mm accubonds max out at only 160gr with considerably lower SD and BC.

    Even with bullet construction and tougher animals left out of the equation, my head is still spinning as to which caliber bullet combination will produce the maximum ballistic advantage at 800+ yards. (Using the same case)

    Just a note: Please don’t throw .338 into the mix – I’m only thinking about 7mm or 30cal for this “light gun”.
  2. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

    Mar 12, 2002
    I have taken deer and caribou over 1000 yards with the amax bullet. I do not use these on elk or moose. If you are splitting hairs like this you need to look at specialty bullets like the gs, cutting edge, wildcat, etc. I don't know what a Jazz is. If it is a necked 8mm rem mag then either will satisfy you. The only concern is caribou is in grizzly country and I like the larger caliber there. If the Jazz is larger than the 8mm rem mag case it is very simple. Go with the 30 cal so you will not need a new barrel when you get your load worked up for it. With good barrel life the 8mm rem mag case is as big as I have been able to go in 7mm. In 30 cal you can move up to the lapua and RUM cases with respectable barrel life.

    Look in that thread on 7mm remington vs 300 winchester and see if that helps. However the winchester is a larger case so not a good comparison for what you are talking about. I can just tell you I can kill any deer or caribou with either in the same case. I think hunting and shooting skills are going to play far more of a role than splitting hairs of these two calibers. I can tell you from much hunting experience I will always go with the largest caliber all else being about equal. I could easily take either with my 7mm STW's and a 162 amax at 1000 yards. I can shoot that bullet at 3250 fps out of it.

    Here is a comparison apples to apples from two I have shot extensively since the 70's. 7mm-300 wby vs 300 wby. 7mm-300 wby 162 amax accuracy load at 3270 fps. 300 wby 180 grain accuracy load 3240 fps. 7mm-300 accuracy load with 180 berger=3090 fps. 300 wby accuracy load with 208-210 grain=3030 fps. These are accuracy loads in my rifles out of the same case 7mm vs 30 cal. Run the numbers. I shoot all of them so I am not getting into a peeing contest of which is best. I can kill with either. Hope this helps.

  3. elkaholic

    elkaholic Well-Known Member

    Dec 4, 2008
    As LTLR says, you are probably splitting hairs a bit but I would run the #'s on the bullets you think you will be using and choose the one with the shortest tof. The largest factor in a hit or miss will be wind drift as either choice will kill if it hits......Rich