7mm AM vs .300 WM

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by TARGETMAN, Jan 7, 2009.


    TARGETMAN Active Member

    Jan 4, 2009
    Hello eveyone, Im new to the forum here.

    I have finally decided to build a custom long range hunting rifle and cant really decide on the best caliber. This rifle will be used for elk, muleys, kudu, and at least once on an eland (if the good Lord is willing). I have some what narrowed my list down to the .300 Win Mag and the 7mm Allen Mag. I am 5'10" and 160 lbs so I am concerned with recoil. The rifle should not exceed 9 lbs and 26" barrel so as to make it more friendly on my mountain hunts. My Kimber .325 WSM has a sharp recoil but I can manage it well (I think I can shoot better than this particular rifle!) The 7mm AM should be sufficient on the large eland with 175 grainers out to 500+ I would think, certainly adequate for the other large critters. I like the .300 for 200 and 220 grainer capability but my all purpose load wiould be the 180 grainer. SO..., is there any other calibers that you would recommend? Thoughts, comments, suggestion?

    HELP! Thanks in advance.
  2. Tyler Kemp

    Tyler Kemp SPONSOR

    Aug 10, 2006
    The Allen Mag whoops the 300 Win in every category. Shooting 180 Bergers or 200 Wildcats it will trounce the 300 in drop, wind, ft lbs, and most likely accuracy.

    You'd probably want a brake on a light gun though.

  3. WildcatB

    WildcatB Well-Known Member

    Jan 27, 2008
    My vote is for the 7mm AM. It's on top of the pile for longrange hunting.
  4. Derek M.

    Derek M. Well-Known Member

    Jul 12, 2004
    There are plenty of reasons to get either. For decades, many who prefer to be a "one gun" hunter choose the venerable 300 WM, and for good reason. It simply works and works well. The hole is bigger, the bullet wt selection is heavier, it is a very accurate caliber. It is an excellent choice.

    I do not have personal knowledge of the 7AM other than what I've read here. It appears to be an excellent choice for a do-all rifle. To be blunt, if a 140 Berger VLD from a 6.5x284 can dump a bull elk at 900+ yards, there's nothing either of your two choices can't do better.

    If you are to travel across the world to hunt, you can find 300 WM ammo just about anywhere. Not so with the AM. So, if you go on a hunt of a lifetime and your 7mm AM ammo is a no show, you are out of luck. I guess that would be the only downside of any wildcat or semi-uncommon caliber.

    Kirby built a rifle for me in 270AM and did an excellent job. The rifle shoots very well.

    Good luck with your decision.
  5. Buffalobob

    Buffalobob Writers Guild

    Jun 12, 2001
    I own a 7AM and for the purposes you describe, it hardly sounds like the cartridge of choice. It is best with a lot of barrel length to burn all of the powder. A 7mm AM is the ultimate ultra-long range 7mm. Kirby has a "small" green stocked 7AM he hunts with a lot and I do not know the weight of it. Maybe it meets your criteria. For a under 600 yard rifle for elk sized animals it would seem to me that the slightly smaller 7mm's would be easier to build a rifle to meet your specification and do the job just as well. I killed a near B&C wild bison with a 7 Wby. I don't think an eland or kudu is bigger than that.

    So, if it was me and I was building a rifle for shooting animals under 1000 yards a 7STW is what I would compare to a 300 WM. I am a fan of the 7mm but I personally don't see much difference in killing ability of the two cartridges at the ranges you talk about.

    Kirby does build a lot of rifles that are not Allen Mags, so it is not like he can't put in whatever chamber you would like.
  6. 7mmSendaro

    7mmSendaro Well-Known Member

    Feb 9, 2007
    Kirby built a 300WM for me on a Weatherby Vanguard action that is a great shooter! It would be hard to beat for your purposes.
  7. davewilson

    davewilson Well-Known Member

    Feb 19, 2004
    i basically agree with everything said. my concept of a 7AM is it's a serious long range cartridge. my gut feeling is you don't have much experience with long range and i wouldn't recommend a 7AM. the 300WM is also a great cartridge, can do everything you want.

    my suggestion would be to use the 325WSM. it will also do everything you want. bullet selection is not as good but you can probably find something that will work well. get the gun accurized and shoot it a year or so. then decide what you want to build.
  8. grit

    grit Well-Known Member

    Mar 23, 2005
    I went with the 7Dakota, a big step down from the dragster 7AM. BB and Dave are spot on.

    Myself, having my first custon built, I wanted something a little special. Frankly the 7wsm or 7rem would have suited my needs fine. But, the Dakota is a neat round, with a significant increase in performance.

    The choice between the 300win and a 7AM is surprising. Completely different ends of the spectrum. One a conservative, readily available, easy to load and shoot round, the other a top fuel dragster, requiring costly brass, custom dies, and fireforming. Still, an impressive round.

    For my Dakota, I wanted an all around, mid weight, long range capable, but still comfortable to carry rifle.

    It is my opinion the 300 win is underrated in todays magnum minded world. With my 210 grain berger load, I consider the cartridge 1500 yard capable. Wether I can get the bullet there is another matter.

    All that said, if you really want the 7AM it is nothing short of awesome.
  9. Lightvarmint

    Lightvarmint Guest


    If you are stuck on the 7MM bore the 7MM RUM is a little smaller than the 7MM AM. Benefit of that is that you have a chance at getting one that will shoot as good as some customs if you get one of the Sendero models. The only pickle is that you can't get one in a super fast twist to shoot long bearing surfaced bullets..... If you are shooting factory bullets and/or ammo this may be your ticket.

    We have found that with properly tuned ammo (both factory and reloaded), epoxy skim bedding and aftermarket trigger installation, that most factory barrelled Remington Senderos will shoot as good as the group size guarantee you get from most custom gunsmiths.

    We have done it with .270s, 300 RUMs, 30-06, 280s and 338 RUMS. I was so impressed with the 338 RUMs, that I bought a very nice one the other day just because I did not have one and I really did not even need it. I may even sell it..... Who knows.

    In short, I have many custom rifles and pistols and I can still make the case for the factory Remington Senderos.... Simply put, they work better than what you pay for.

    Hope this helps you out.

  10. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Jun 12, 2004
    For 600 yard shooting and under, the 7mm AM is alot of rifle. If you want one just to have one, it certainly will work fine. Making a 600 yard shot with this chambering in a quality rifle is hardly a challange, even with conventional bullets. Still, its extremely fast for conventional bullets. You are looking at 3450 fps with 160 gr class bullets in 26" barrel lengths. I generally load down a bit to 3375 just to give the bullets a bit of a break and you still have around 100 fps over what the 7mm RUM will get in the same barrel length with comparible case life.

    That said, the 7mm AM is what it is, the top of the pile in the 7mm family of chamberings. As such, it has its querks that need to be delt with. Extreme performance always comes at a cost, barrel life is the main one. Not a huge deal to a big big game hunter but its a consideration that has to be mentioned. Not noticably harder on barrels then a 7mm RUM class round but a bit.

    It also really should be used with slow ball powders which raises some other issues, have to stay on top of carbon fouling. Also have to realize that environmental conditions changes will have slightly more effect on trajectory then the smaller chamberings. Especially with the ultra heavy custom bullets.

    The longer the bullets baring surface, the larger the capacity and the faster the twist, the more effect temp changes will have on velocity, no matter what powders you use. Just a fact of life. Is this enough to cause problems, generally not if your aware of it and prepare for it.

    Its bonuses, flat out shear horsepower and ballistic performance. When the 200 gr ULD RBBTs come back on line, there is really nothing that will run with it, especially in a +28" barrel. Really the only thing that will are the big 408 CT based 338 magnums and thats it.

    Recoil is very managable, with a quality muzzle brake, its really nonexistant to be honest, even in a relatively lightweight rifle. Its also accurate, very accurate which has been proven and reported on by MANY dozens of times here on LRH.

    On game performance is also extremely good. Far more then most would ever expect from any 7mm magnum chambered rifle. In fact, from the game I have taken with the 7mm AM which is now several dozen big game animals, its terminal performance seems to be right there with the largest 30 cal magnums.

    At 600 yards and under, bullet selection needs to be considered critical, especially if the game will be larger in size. I was able to put my 7mm AM to a real test this last fall on a moose hunt. In my old lightweight 7mm AM which is in severe need of a new barrel, I am using the 160 gr Accubond loaded right at 3380 fps out of a 26" barrel. This is because the wear on the barrel prevents me from shooting the 200 gr ULD RBBTs, just to hard on the jackets and they come apart.

    I was concerned with bullet performance on moose size game but figured that if the shot was over 300 yards I should not have a problem as I would avoid any large support bones.

    Well, it did not turn out that way, the young but large bull I harvested was only 150 yards away when I shot him the first time. He was running broadside to me and the first shot broke his onside shoulder. He ran another 50 yards or so and my second shot landed a bit higher and the bull fell. He then got up again and a final shot at the shoulder/neck junction put him down for the count.

    When we skinned the bull, the first two bullets were found just under the offside hide. Which impressed me to be honest at that launch speed and on that size of an animal(1000 lb). The third shot exited through the front of the shoulders.

    The first bullet retained 101 grains of weight and the second 115 grains.

    Though they did the job on the moose, I personally feel that for game larger then 500 lbs, its still best to step up to a larger caliber bullet simply to move and damage a larger amount of vital tissue during penetration. For game the size of elk or larger, especially at ranges out past 800 yards, I certainly recommend a larger diameter bullet just for those occasions when things do not go just as we have planned.....

    That said, you are not planning on shooting past 600 yards. Is a 7mm AM needed? NEEDED? No, its not, certainly not. But it also will not hinder you either if you know the issues it has and prepare for them, just like any other chambering.

    Its abit spendier to load for then a factory chambering mainly because of brass cost which you can purchase preformed brass from me for a fireforming fee but it eliminates any need to fireform brass.

    Most would be suprised that I talk far more customers out of my wildcat chamberings they rifles I actually make in them. In fact, I would say I talk 3-4 out of them for every one I acutally build and ship to customers. Why, well, once I find out what they will be doing with the rifle, I usually determine that they really do not need the hyper performance of a chambering like my wildcats. In such case, we talk things over and come up with a more conventional chambering that will cover their needs perfectly and go that route. Now, if you just want a 7mm AM, no problem there, it will serve you well.

    As far as the 300 Win Mag goes, what can I say about the old Win Mag. Its not sexy anymore but it works and works great. Reliable, easy to load for, list of usible componants that is so long its hard to believe. Not much more needs to be said about it.
  11. phorwath

    phorwath Well-Known Member

    Apr 4, 2005
    What impact velocity are you talking at 1500 yds? 1600 fps @ 10,000 ft elevation? 1400 fps @ 5000 ft elevation? 1100 fps @ 300 ft elevation? That's why I don't consider the 300 Win Mag a 1500 yd cartridge for taking large game, even with a good hit at 1500 yds. No way to know what kind of bullet performance you'll get at those low impact velocities.