7mm SWT vs. 7mm Allen Mag


Feb 18, 2008
I have neither.... but I would chose the Allen hands down... simply because it out-performs the STW in every way. The main advantage of the STW is over-the-counter ammo by my way of thinking.


Well-Known Member
Jan 20, 2004
Blackfoot, Idaho
What trj said.

Also, over the counter ammunition availably? Think about it. How hard does one have to work to get into a situation where ammunition availability would be come a problem.


7mm STW by far. It doesnt require special dies, loads of load development and is very load friendly. Not knocking Kirbys brilliant line of mags but they do require a special amount of work to get to shoot right. The 7mm can be a finicky caliber when extreme overbore is encountered. This may not be what your after.

The 7mm stw only downfall is its a belted mag and to some the belt equates to less accurate. While this may be the case I have yet to see a difference and have enjoyed years of accuracy with my couple of 7mm stw's. In a 34 inch barrel behind 74.5 grains of H1000 I was able to get 3100 fps using Berger's 180 grain VLD's. This far exceeded the 7mm Ultra factory offered heaviest bullets in a shorter barrel burning more powder.

The ultra however if chambered in this same barrel would probably offer 3300~3350 or so this would be a substantial benefit and worth it. If your end product is within 100 fps of each other the difference between them at 1000 yards is hardly noticeable but if you plan on going out to 1500 and beyond then something else may be needed. Anything out to 500~700 yards is all velocity beyond that is BC and velocity.

Sometimes in the quest for the best you end up spending more time in the garage/shop and range than you do hunting or enjoyable shooting. Spending loads of time and travel trying to find the perfect combo of powder, bullets, and group size can be overwhelming.

A lot of these magnum wildcats require some load development. What the fellas on here are getting didnt happen with one load and a trip to the range it tooks some months to find the right combo.

The stw if chambered in a 1:9 twist barrel by a good barrel company will like powders in the range of the H1000, Retumbo, US869, RE22, RE 25 with bullet weights in the 168~180 class with great results. Loads of data exist on the net and on here and you can usually get a few loads ya like and they'll also perform the same in your weapon as they did in the others.

I enjoyed the 7mm STW and its accuracy as well as its forgiveness in small loading differences. I am currently upgrading the wifes gun to a new Bartlein barrel in a 1:9 twist Sendero contour finished at 26 inches fluted 5R rifling. I know it will be a screamer and I dont even have the barrel yet. I thought about the 7mm WSM, the 7mm Ultra and yes even the 7mm Allen mag.

I want a fun gun right out of the starting gate and I know this will do it. Most of the other cartridges when you get into 100 grains of water capacity are a waste unless you intend to extract every ounce of performance. Huge cases require longer barrels to take advantage of all that powder and that means heavier guns unless you want to dump $800~$1000 in an ABS wrapped barrel at which point you should go with one of the 100 grain capacity cartridges as money must be no object :).



Well-Known Member
Feb 7, 2005
Texas born and raised
As Daveosok said, if you want the top end velocity for that caliber Kirby is the one to talk to. He builds a great rifle no doubt and does have a niche in the velocity dept with his creations. However, as was also mentioned his creations might not be for everyone. Unless your looking to squeeze every inch out of your capabilities, then yo umight be better suited working into one of his rigs.

Myself I had him build me one of his .270's for some long range work on feral hogs. I wanted something that would shoot far as I felt was feasable under the conditions and anchor them on the spot with out wasting too much. What he built me works wonders if I can do my part out to 800yds easily and then some. However my furtherest shot has only been just a tad over 450.

I picked up a used STW and figured that I might as well see if it would shoot before using it for a donor program. I bought up a couple of boxes of Federal ammo loaded with the 150gr Nosler Solid Base. THey run right at 3250 from my rifle and have generally grouped at or under 1" at 200yds. from the bench. I figured that I might as well grab some while they were on sale and picked up 10 boxes for around 15 bucks a box. Since then I have not tried but a couple of times to work up a load using a heavier bullet. I mostly just grab up a handful of the Federals and head out with it. I did manage to grab up some cases to actually do load development with but just haven't seen the need. I can drop anything I am after with the 150's and they match right up with the Burris scope I mounted on top of it out to 600yds. All I need to do is hold for the wind and adjust the dot for the range. Dies were easily obtialned and under $40 for the set. Powder isn't a concern as so far I have only tried a few that I have on hand. Should I need to I can easily obtail something which will be suitable for several weight bullets. It might not be THE poder for all of them but hey I only shoot it a couple times a year. Same as the .270 Allen Mag, I have somewhere around 250 rounds down the tube maybe a few more. Generally I only bust one occaisionally to see if I can still hit that little plate way across our back pasture. They are both great rifles but I think if I had found the STW first, I would have probably not had the .270.

Now however I have both and just got a new toy to break in.


Official LRH Sponsor
Jun 12, 2004
Fort Shaw, Montana
While your question seems simple enough, it really is quite compicated because if a customer came to me with that question, it would be followed by a volly of return questions to help me figure out what this potential customer really needs in a rifle to meet his goals for a new rifle.

If you will not be shooting more then 600 yards, there is really no REAL reason for the added horsepower of the 7mm Allen Magnum. It certainly does not hurt at closer ranges, just makes hitting your target a bit easier in some cases but its not needed and it does have a shorter barrel life then the STW.

If you want the ultimate in consistant 7mm long range power, there is no real choice, a 200 gr ULD RBBT loaded to 3200 fps in a 27" barrel out of the 7mm Allen Magnum is simply something that has to be witnessed to believe ballistically.

A 160 gr Accubond loaded to 3500 fps in a 27' barrel, again, is a wonder to play with.

That said, out to 600 yards, is it needed, not really.+1/2 mile, thats where the 7mm Allen Magnum really shines over its smaller brothers.

Dies for the 7mm AM are more expensive but this is just a one time expense so I generally do not recommend to use this as a decision breaker either way.

brass is much cheaper for the STW at this time if you can find it. Getting hard to find but it is still out there. Nosler will be starting to make STW brass soon as well but this will bring its cost much closer to that of the 338 Lapua which is the parent case of the 7mm AM.

Brass quality, no contest, far in the favor of the Allen Magnum with the Lapua case.

Formed cases, I offer formed cases for my customers so there is no need for the customer to spend the money and loss of barrel life fireforming brass. Costs a bit for the formed brass but case forming is no longer an issue for customers if it was a decision breaker.

Rifles for a 7mm Allen Magnum will be slightly more expensive simply because of the modifications needed for the fatter chambering to feed well. If you want a single shot, really not much difference in price.

Simply put, from the designer of the 7mm Allen Magnum, as mentioned, it is not for everyone, its not needed for may situations compared to the smaller 7mm chamberings. You have to decide what is needed to cover your goals for the rifle. Again, if you will never shoot over 600 yards, hell, even 800 yards, the 7mm AM is not needed, the 7mm Rem Mag, 7mm STW or RUM will all do this easily.

If you want to shoot this range on heavier game or extend your range well past 800 yards and even well past 1000 yards, the 7mm AM will really shine and show its worth over the smaller 7mm magnums.

If you just want to have the highest performing, practical 7mm around, the 7mm AM is pretty much there.

Really it comes down to what you want to do with this rifle. I recommend lesser 7mm chamberings 2 to 1 over my 7mm Allen Magnum chambering simply because those customers do not need this level of specialized equipment to do what they want to do with their new rifle.

My goal is to get them what will work the best, not to sell my Allen Magnum rifles. I only recommend them when they will be the best for the application at hand.

Tell us what you want to do with the rifle and we will be able to offer you a better idea which would be better for you.

Kirby Allen(50)


Well-Known Member
Jun 11, 2005
Yakima, Washington
I had a STW but sold it, have a 7mm Rem Mag and have had many over the years, also have a 7mm Wby and I also have a 7mm Allen Magnum.

This is Long Range Hunting. Now, if your definition of long is 600-700 yards or less, and if the factory ammo thing worries you, and if money might be a problem then I'd say go with the factory setups. When is the last time that any of you have had to not hunt with a wildcat because you couldn't find factory ammo? I've been loading for longer than most can imagine and have never had my ammo supply become a problem. Planning helps a lot.

If you want the best performance you can get at loooong ranges them the 7mm Allen Mag is the winner hands down.

The 7mm AM has been the easiest 7mm to work up a load for that I've ever worked with. I've found nothing picky about it and had far more problems finding a load for one 7mm RM that I had.

There are no "special dies" needed for the 7mm AM. You simply buy a set from Kirby just like you'd buy a set for an STW or any other gun.

I believe that I have in my 7mm AM the best long range 7mm available. I spend far more time hunting and shooting with this gun than with any factory gun I've ever had. Months to find the right load for my 7mm AM......nope, sorry. Simple and easy and no matter what bullet weight I try it likes them from 160s up to 200s.

I read a lot about the AMs being bound by one bullet or picky to load or time consuming but I find it to be the opposite.

I'm not knocking the factory rounds. If that's you piece of cake then cut it and eat it. If you want the absolute best long range 7mm then for me it's the 7mm AM. I guess in the end it might also come down to money as building a 7mm AM is probably going to cost you more than buying a factory gun. But remember, if you start putting money in the factory gun, where and when do you stop and how much can you spend to be cost effective by using the factory over custom or semi custom?

Just my $ .02 worth. Take it for what it's worth.;) However it kinda looks like, other than Kirby, my opinion was the only one that included experience with both rounds mentioned. Even if you go with the STW you will be very pleased and it is capable of killing game at long ranges.:)
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Official LRH Sponsor
Mar 26, 2006
Tumwater, WA
Well....I have both. It depends on what a guy is looking for and what you plan on doing with the rifle. I get 3340fps with the 168 Bergers out of my 28" STW barrel, and I get 3330fps with the 200gr WC out of my 30" Allen Mag barrel. For everyday shooting, the STW probably gets the nod. If you were starting from scratch and Kirby hadn't already done so much work with the Allen Mag, I would say the STW would be easier to load for. A guy can usually use Kirby's loads with the AM, and fudge the charge a little one way or another, and it shoots great. There is an incredible difference at 1000yds when the 2 bullets hit rocks. I did do a little work with the 180's in my STW, but I had 1000 168's to burn through first. Even with the 180's going around 3200, the Allen Mag still hit harder. Case forming is kinda a pain, but it is only a one time ordeal. I have given my STW to the wife and now use my 338 Edge and the 7mmAM as my main go to rifles. I don't see how you can go wrong with either rifle.


In an original thread back in 2002 I tested a bunch of powders and bullets. In my weak 7mm STW I managed to hit 3493 fps with 75 grains of N560 without the need for a Lapua sized cartridge shooting the LRB 162 gr J40 bullets.

In some cases you don't need such a big case to achieve some of the fastest velocities.

I also knocked on the door around 3500 with the 168 SMK in 7mm with my STW.

Now I see no benefit between the Lapua based wildcat and the stw since I was able to acheive the speeds listed in the post on here with a 1/4 of the powder less but in a 34 inch barrel.

I also hit 3100 with the 180 gr Bergers in a very conservative loading of 74.5 grains of H1000.

Dan Lilja goes into great depth on diminishing returns on hsi website and at some point with all these huge cases your going to see it. The only way to obtain the most out of these large cases is very long barrels.

At shorter barrel lengths its simply not worth the money unless your in an argument and need the male length to subconsciously help you win it.

BTW 3100 fps with the 180 and 3493 with the 168 is plenty good for 1000 yard shooting and taking game.


Well-Known Member
May 13, 2007
Kirby recommended and is building a 7 STW African plains game rifle for me. (Rem 700 mag action, Lilja barrel, Manner's GAT stock).

I won't be after buffalo or eland, or shooting at more than the above mentioned 600-700 yrds., so the 7 STW should be about perfect.


Well-Known Member
Jun 12, 2001
Potomac River
The 7STW is a great cartridge and may be just what you need. For many years I shot a 7mm Wby as my long range rifle and I guess I know what its good points are and what its limitations are. If you are shooting small eastern deer or antelope the 7STW has more lethal range than most people will ever need. However, if you want better performance in the wind and or longer range on bigger animals then the 7AM is great.

The differences between the 7STW and the 7AM is that the 7AM has just about double the lethal range on hoofed big game. On elk, that is about 1800 yards and on the smaller stuff it is beyond 2K. My goal was to build my last great elk rifle with a capability to 1500 yards and I am more than happy with it. The extra margin of safety of having killing power to a mile is great. Last season, I watched a large bull and I could range a flat rock face with the Bushnell 1500 at a distance of 1680 yards. The bull was 100 to 150 yards beyond the rock face. In other words he was beyond a mile. The rifle was capable of the shot but without an accurate range the shot could not be taken. The issue is not the rifle, but the rangefinders.

There is little if any load development with a 7mm Allen Magnum. Kirby tests the rifle before he sends it and it comes to you shooting better than 0.5 MOA. He will tell you the load he used to do that. He told me he shot the group with 102 grains of US 869 and I use 103 grains. This is a 34 inch barrel and Kirby chrono’ed the 102 grain load at 3340 fps. The max recommended load is 105 grains. Of course with a Nesika M action I can run the loads way higher if I wish, but being as I am not yet out to the margins of the rifle’s capability, I do not have to ruin my brass pushing any harder. The furtherest group I have shot with it is 1563 yards and four rounds went into 0.488 MOA. So there is no question concerning the accuracy of the 7AM and 200 grain Wildcat at long range. The heavier bullet with the higher BC has way more momentum downrange than the lighter bullets and that is what makes it a one mile cartridge. In the next few months I will get some data out to 2K or more.

The loading dies are just as simple as the 7STW because Kirby sends you what you need. If you order the fire formed brass then it is a two die set, a full length sizer and a competition seater. If you want to form your own then it is a three die set and there is a die for reducing the neck from 338 to about 308 or so. Just so we don’t get too confused about accurate reloading techniques, I use a three die set for a 308 F-class rifle

Forming brass is by running it through the neck reducer and then through the full length die and finally using the corn meal method. It will take most of a day to get it all blown out and the barrel cleaned and the brass re-prepped and into the tumbler. I am certainly no benchrest reloader and I can hold runout to about 0.0015.

I use my 7AM for what it was built for and it does what it is supposed to do. So, be realistic about what you want to do with the rifle and how you want to hunt and select the cartridge based upon that.



Well-Known Member
Dec 8, 2007
You cant go wrong with either cartidge. They would each be fun to shoot. I went a different route and did the Lazzeroni Firebird and the 7 Ultra! Both are fun toys!!!