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Why Not the 7mm?

Discussion in 'Rifle Country' started by Welding Rod, Dec 12, 2009.

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  1. Welding Rod

    Welding Rod Member

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    When looking at many rifles billed as long distance "tactical" shooters it seems 308, 300 win mag, and 338 Lapua are the common offerings and picks.

    Why does there seem to be little love for the 7mm Rem Mag for this application?

    Am I missing something or isn't it ballistically superior to those three cartridges? And substanstially superior to the first two?

    It certainly should have adequate punch for human use at extreme long long distance, roughly doubling the energy of the 308 at 1,000 yards.

    All with reasonable recoil.

    I can see some picking a 308 for low recoil, long barrel life, ammo availability at a low cost, handy short action, etc in exchange for reach.

    But as far as the other two as an anti-man rifle, what am I missing?
     
  2. jlbpa

    jlbpa Member

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    best shot I ever witnessed was a remington 700 bdl on a ground hog so far away I couldn't even make it out with naked eye. But I did see the dust and the ground hog flop when the 7mm dusted it.
     
  3. The_Pretender

    The_Pretender Member

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    Too Many Considerations

    There are many factors to consider when selecting a cartridge. You have to pick your intended purpose, ranges, conditions, personal preference within the set guidelines, etc. etc.

    I have no doubt the 7mm mag will put someone on their ass. But when you're talking about 1000 yards, the bullet can be affected by gravity, temperature, moisture and wind a lot more than a heavier grain and better makeup of the larger .30 cals.

    Use what you feel most comfortable with. There isn't a right answer to anything, it's not written on a rock somewhere that 7mm mag isn't enough. 300 win mag and .338 Lapua are utizlied by many sniper units around the world. A 300 win with 178g matchgrade ammo will deliver outstanding accuracy at long ranges. Not to mention drop an anvil on something 1000 yards out.

    A .338 Lapua will fight wind even better and deliver a mortal blow through layers of clothing and body armor. Something else to consider at that range.

    Getting there isn't the problem. I've watched people shoot 800 some yards with .223.

    It's what you do when you get there that counts.

    Good luck and happy shooting.

    edit: typos
     
  4. Welding Rod

    Welding Rod Member

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    Isn't speed and BC what beats environmental factors?
     
  5. Slamfire

    Slamfire Member

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    Spoken like someone who has never shot an 8 at 1000 yards.

    I've shot 6's. :neener:
     
  6. Snakum

    Snakum Member

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    The 7mm has, at times, been used by various services all over the world as an agency sniper rifle. In fact the US Secret Service used at one time. The ballistics of the hottest 7mm factory loads are superior to everything else short of the .300 Win Mag - which brings a LOT more recoil (and yes ... I've owed both). It shoots flatter, with more energy at all ranges, than anything else under 300 win mag. I am sitting here looking at the numbers for all Remington and Federal factory loads for everything from .270 to .300WSM. The 7mm is king for trajectory and power. And that's why it was one of the best selling rifles for many, many years.

    All that said, however, other rounds such as the .308 and especially the 30-06 are for more flexible and have many more weights and bullet types available. Also, the .308 is a very, very accurate round. I read something once about the .308 round and equipment being easier to wring extreme accuracy out of. Dunno if it's true. Anyway, as said, the raw numbers don't always tell the whole story. 7mm kicks harder than the .308 and a little harder than the -06 and recoil can be an issue for some agencies and for some people. 7mm mag ammo is expensive, too.

    For me, the 7mm will always be number one. For what I do (deer, bear, varmints, long range paper punching) it serves me perfectly. I am looking at all the numbers tonight because I want a new rifle, and once again the 7mm makes the most sense. So I'm emailing around for another Winchester Model 70 in 7mm mag or a Savage 116 Stainless 7mm mag with the Accustock/Accutrigger and muzzle brake. I'd even take one without the muzzle brake. Me likee 7 mil. :)
     
  7. ArmedBear

    ArmedBear Member

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    .308 was designed for guns like the M14. It's based on the ballistics of the old Garand-compatible (weak) .30-06 military rounds. It's not a bad round, but it's sure not the end-all of long-distance sniper rounds, either.

    The reason it soldiers on is simple: a huge installed base. It's become a standard. Rounds around 7mm were recommended by diverse experts for the Garand, but the .30-06 was already a standard at the time, and really, 7mm isn't THAT different.

    .300 Win Mag and .338 Lapua, OTOH, are chosen specifically for their ballistics, not just because they were lying around in large quantities.
     
  8. Maverick223

    Maverick223 Member

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    There are several shooters that choose the 7mmRM, it has a better trajectory than the .300WM and bucks the wind just about as good, with nearly as much energy...and it has a good bit less recoil in a lighter rifle.

    :)
     
  9. Bluenote

    Bluenote Member

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    When looking at many rifles billed as long distance "tactical" shooters it seems 308, 300 win mag, and 338 Lapua are the common offerings and picks.

    Why does there seem to be little love for the 7mm Rem Mag for this application?

    Am I missing something or isn't it ballistically superior to those three cartridges? And substanstially superior to the first two?

    It certainly should have adequate punch for human use at extreme long long distance, roughly doubling the energy of the 308 at 1,000 yards.

    All with reasonable recoil.

    I can see some picking a 308 for low recoil, long barrel life, ammo availability at a low cost, handy short action, etc in exchange for reach.

    But as far as the other two as an anti-man rifle, what am I missing?
    ****************************************************


    I shoot 7mm mag , and do so at extended distances , it always goes along with the rest of my 'golf bag' at varmint shoots. And I see quite a few other guys showing up with them , so the 'love' is there at least among the varmint crowd. And in the long run one can learn more about long distance shooting under real world field conditions from the varmint crowd than one can from the benchrest competition crowd.

    I still keep a .338 mag for the far north , but it may well get sold off as I'm giving serious consideration to a .375 rum I ran across to replace it for the same purpose.

    And to each their own but personally I've just never cared much for .308.
     
  10. Maverick223

    Maverick223 Member

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    Yes, you are missing a lot. The .338LM has much better ballistics, but that comes at a much greater cost and a whole lot more recoil energy (= muzzle brake). The .300WM also has a little more energy than the 7mmRM, and bucks the wind a little better, but it also has more recoil and drop. I think the biggest factor is factory match cartridges (as well as bullet selection) for .308cal. is more abundant than for 7mms.

    :)
     
  11. ArmedBear

    ArmedBear Member

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    Yeah, if cost, recoil, rifle weight and barrel life didn't matter, we could all just shoot .338-378 and just be done with it. Hell, why not .50 BMG?:)

    EVERY cartridge is a compromise between multiple competing factors.
     
  12. Welding Rod

    Welding Rod Member

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    See Maverick that is where I am confused.... how can the 300 win mag "buck the wind better" if a 7mm RM can shoot an equivalent or higher BC bullet as fast or faster?

    Edit - I just learned some things about 338 bullets... there are some ~ 300 grainers available with some incredible BCs. It appears the cartridge can push these around 2,700 FPS or slightly better. Wow... that is something. I was not aware of these very heavy bullets and that the 338 LM had the ability to push them that fast.
     
    Last edited: Dec 12, 2009
  13. rangerruck

    rangerruck Member

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    I think as far as long distance paperpunching/target shooting goes, for a long time, there were just better made bullets for other cals, not so much for the 7mm bullet category. But that has change alot in the last 5 years, and you can now get some very nice made 7milly bullets, from the 160's up into the 200 range , I believe. A vld bullet in 7, with a weight of either 180 or 200 grains, has got to have some huge b.c. numbers, and still be fast as heck.
    Also , a dude about 2 years ago, shot a world record group at 1000m's, using a wildcat round; a 7mm/300wsm. Basically a 300 wsm case necked down to take a 7mm round. Very nice idea; I am really digging that loading for a wsm; as it is now, the 270 wsm makes up the most ground from it's parent cartridge. The 300 wsm makes up a bit, but a 7 bullet on a 300 wsm case, has to make up some serious speed gains, and do it in a short fat case, that is allways a plus.
     
  14. Maverick223

    Maverick223 Member

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    Perhaps I am wrong (just going off of memory), but the .300WM will handle wind a little better than the 7mmRM with the best BC bullets (and there may very well be a 7mm projectile that bests that now). There are some very high BC projectiles for .308cal. cartridges, well over .70 (and nearly .80 with the heaviest of SMKs), I believe that the 7mm is limited to a sub-.70 BC. But the speed of the cartridge still makes it fly a little flatter, at least at practical ranges. The .338LM just beats the snot out of anything sub-.40cal (other than wildcats) due to far superior ballistics, but that comes at great cost.

    :)
     
  15. Uncle Mike

    Uncle Mike Member

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    There is no replacement for displacement! Thin may be in...but fat's were it's at!

    The weight of the projectile wins, between the two.
     
  16. Utah1

    Utah1 Member

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    In 7mm the 180 Berger has a BC of .659, the 175gr SMK .608. I don't think you'll find off the shelf ammo for these rounds, but I'd imagine most shooters would be handloading at this point anyway. With the .30 cal bullets you have to move beyond the 190SMK (BC.533) and up to the larger offerings to get better BCs. 240SMK has a BC of .771. The 210 and 220 SMKs, run in the low .600s. The Berger offerings are low .600s as well. The 208gr AMAX is at .648.

    If I'm not mistaken the 240SMK needs a rifle throated for that bullet. I think the military is starting to use this bullet as well in 300WM.

    6.5mm, 7mm, 30cal, all can and do shoot great. The recent 1000yd world record group was shot with a 300 Weatherby Mag. However, 6.5-284 loadings are doing well also at that range. I'd think the 7mm is the clear winner over the 308 and the 30-06. You'd have to be using a WM, RUM, or something like that to push the heavy bullets fast enough in a .30.
     
  17. Maverick223

    Maverick223 Member

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    Not sure, but I don't see why you couldn't just set it back in the case a little farther (but that is one heck of a long projectile). I am currently shooting the 208gr. A-Max, but I have considered giving the 240s a shot, just not sure if it will stabilize properly in my 1 in 11" twist Krieger (I am doubtful, especially with the reduced powder and velocity).

    :)
     
  18. buttrap

    buttrap Member

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    For my two bits what you are missing is with a heavy long range slug they dont do as well as your basic .308 or 30-06 or dont exceed what they can do by enought to worry about all the odd guns they come in. Plus they kick harder pushing the same weight slug as a 06 at about the same speed too.
     
  19. Jim Watson

    Jim Watson Member

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    Depends on your application.
    The military has got a lot of .308s, some .300 WM, some 338 Lap, some .50 BMG. They are not going to add another caliber to the supply chain for a small theoretical advantage.

    The target shooter shoots a lot. The .300 WM used to be the Long Range caliber of choice, if you didn't shoot a .30-338. But recoil mounts up over a day on the range and smart shooters moved to the 6.5x284 or something similar. Some shooters are now working down in the 6mm class; but some others have moved back up to 7mm looking for a new compromise between recoil and ballistics. They aren't shooting the 7mm RM, though. The belted magnum has never been real popular among heavy use shooters/handloaders, they just used .300 WM because that is what was available. Now there are more choices. I have reports on 7mm WSM and a 7x270 WSM wildcat.
     
  20. ArmedBear

    ArmedBear Member

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    To put it in terms that are easy to visualize, stand in a 25 MPH crosswind. Throw a tennis ball as hard as you can. Throw a baseball as hard as you can. Which one will be displaced more by the wind?
     
  21. Uncle Mike

    Uncle Mike Member

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    Could you imagine a 240 grain 7mm bullwet...? Hey, we can clone sheep now, why not...?
     
  22. Maverick223

    Maverick223 Member

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    Put it in a 7mm-08 and it will touch the bottom of the case. :D
     
  23. ArmedBear

    ArmedBear Member

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    New wildcat: 7mm-378.:D
     
  24. atblis

    atblis Member

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    Neither here nor there
    7 mm does have a following and is increasing. 7mm WSM. Belts are to be avoided.
     
  25. Welding Rod

    Welding Rod Member

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    What is wrong with belts?
     
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