Rifle Cartridge Wars: The 270Winchester – A closer ballistic comparison
This month we shall take a closer view of the 270Winchester and how it compares to the 7 Rem Mag and the smaller 308Winchester
The following is a closer ballistic comparison of the 270Winchester, 7Rem Mag and 308Winchester. Together we shall go through their ballistic qualities as well as gauging their relevance in a real world scenario. I augur that this article will make you take a closer look at the cartridge and bullet combination you are using as well as question the way you make use of it.
Wherever I travel to, it seems hunters and shooters alike get into the debate between these 3 popular rifle cartridges. Is the 270Winchester an underestimated long range contender? Is the 7 Rem Mag a superior round? Where does the 308Win stand in this competitive rifle cartridge scenario?
Which cartridge most represents you?
A – 270Winchester (I already have one & it’s worked for so many hunters so why change it)
B – 7rem Mag (I Love 7mms, love the ballistic performance and can take out anything way out there)
C – 308Winchester (Ammo I can find anywhere, It’s killed everything under the sun. good enough to shoot FTR and Palma competitively)
In this series of Cartridge Wars – ballistics by Rifletalks, I shall attempt to dispel some myths as well as shed some factual data in ways which I hope will be easier to understand when comparing rifle cartridges. Keep in mind, here we are speaking of rifle cartridges in their standard CIP factory load format.
Factory loaded 270Winchester VS 7 Rem Mag VS 308Winchester
Each of these cartridges, 270Winchester, 7rem mag and 308Winchester can be handloaded to enhanced specs such as longer over all lengths, increased powder capacity, slower powders, better bullets, longer barrels etc. However, most shooters will acquire a rifle with a barrel length from 22-26 inches as made by most factories. Most of these cartridges, will shoot and burn 100% of their powder charge in a 24inch barrel. Naturally longer barrels provide additional speed as well as added challenges of maneuvering longer heavier barrels so let’s stick to 24inch. Having a few 30inch barrels myself, I’m well aware of this.
In order to find some common base line, I chose the loads as loaded by Hornady Precision Hunter ammunition. I shot this ammo in 6.5 Creedmoor and 30-06 and I believe it is outstanding and fairly well priced at around €2.20 a pop.
A closer look at bullet choice
The bullet choice is largely the most important component which connects you to your target. It cannot be overlooked. High ballistic coefficient hunting bullets are not as easy to find although most manufacturers nowadays like Hornady, Berger, Sierra, RWS, Norma and Lapua have all come up with their own line of high ballistic coefficient hunting bullets.
Some cartridges have seen better traction particularly due to their bullets being widely used in other popular cartridges, hence enjoying a wider selection of bullets. Take the 308Winchester (7.62) for instance, you can shoot anything from 110grain to 240grain bullets (if you have the correct rifle twist rate)
308caliber bullets: Source https://www.accurateshooter.com/gear-reviews/bulletguide/
Wherever you are in the world, you will find ready loaded 308Win ammo, bullets as well as powder, primers and rifles chambered for this cartridge. It’s comparable to the Land Rover Defender of rifle cartridges.
The 7 Rem mag also enjoys a huge variety of highly accurate 7mm bullets (.284). 7mm bullets are highly sought after in competition, made popular by cartridges like the 284Win among others as well as being very popular in hunting cartridges like 7×64 brenneke, 280ackley improved, 7×57, 280rem, 7RUM and more recently, the mighty 28 Nosler. Remember, it’s not the cartridge that makes it a hunting round but the bullet it is loaded with and to a large extent the weight of the rifle platform from which it needs to be fired from.
7mm (0.284) Above is an extensive line up of 7mm bullets https://www.accurateshooter.com/gear-reviews/bulletguide/
The 270Winchester on the other hand has enjoyed years as a leading hunting rifle cartridge but what is it’s ballistic performance like compared to the 7rem mag and the 308Winchester?
On my last trip I heard a lot of discussion about the 270win, the 7rem mag and the 308win. It seems all hunters and shooters have owned one of these cartridges, either because they inherited a rifle chambered for this cartridge or else it was just the first rifle they bought.
During our latest trip in the Pyrenees, one guy turns to me and asks, Rod should I change my Voere 270win Luxus for a better mountain hunting rifle? My reply, what are you going to gain over your existing chambering? He said, well I’ll get a flatter shooting round. From my target shooting experience, I know this largely depends on the bullet you are shooting rather than the cartridge or rifle. As soon as I got home, I started digging into this.
I know that the Austrian brand Voere lbw luxus 270win makes high quality rifles having shot their 338 Lapua mag version a few times grouping extremely well at 800m with it. In order to be able to guide this fellow shooter, I decided to show you their performance on 2 different levels, Drop in MOA as well as Windage in MOA. You may then decide for yourself.
In my view, Windage is what really influences my choice of that specific bullet & cartridge combination. Why?
Bullet Drop doesn’t bother me, once I laser my target and given I know my actual muzzle velocity, I will dial in that elevation and that will take care of drop. Irrelevant of how fast a cartridge you are shooting, past 400m they are all going to drop considerably that you will have to use a laser range finder before making the shot and you WILL need to know how much it drops exactly. For the scenario below, I am assuming you have dialed in your elevation after you acquired the ballistic solution from the many ballistic applications out there. I prefer Kestrel as it takes into consideration my real time atmospheric conditions as well as the ballistics and it’s spot on once you true your ballistic trajectory.
Below: Notice how close the 270Winchester is to the 7rem Mag to 700m…. Do you still want to change your rifle mate? Why not try changing the bullet first.
Windage on the other hand is a trickier skill set and comes by practicing sending rounds down range as well as practicing with a wind meter off the range. Most hunters seem not to spend a lot of time on the rifle range, they just zero their rifles at 100m and they set off. If you’re hunting short distance, that approach will be fine. If on the other hand, you’re expecting long shots as in some known regions of the world, that’s not going to cut it.
The wind drift table below shows these 3 popular rifle cartridges 270Winchester, 7 Rem Mag and 308Winchester and their wind drift component. I placed a game animal at 500m to give a practical example. The lateral deflection gives you an idea of how much drift you would get due to wind.
Ok so let’s find out the difference between the 270Winchester, 7Rem Mag and 308Winchester using some numbers and real-world case scenarios.
Let’s take the diagram above. We have a plains game ranged at 500m. We have a 10mph wind blowing from 3 o’clock (Full value wind). Below you can see how much each cartridge/bullet combo will drift, both in inches and MOA. For those new to adjusting for wind in MOA, at 500m/546 yards 1MOA = 5.6inches.
So let’s assume you have dialed in windage for this distance or you’re holding off your shot using the reticle hash marks. Now the wind speed drops to 7mph from 10mph but still blowing from 3 o’clock. This happens often and if you do not notice, you will be caught out. By how much?
Below: Here are the wind drift values for a 7mph wind.
Faster Cartridges like the 7rem mag and 270Winchester matter
If you were shooting a 308Winchester and the wind drops to 7mph, you now need:
16 inches of Right wind hold instead of 23 inches for a right wind, that’s 7inch difference.
Your 270Winchester would need 14 inches instead of 20 inches that’s 6 inches difference while your
7 Rem mag would need 12 inches instead of 17 inches, that’s 5 inches less correction.
Depending on which way the animal is looking, if it where looking into the wind, you would probably just miss it or just hit it as you would have over compensated but if it were looking away from the wind, you would miss and hit the animal in its hind legs.
Below you can picture this scenario where you are taking a shot at 500m in a 10mph from 3 o’clock (known as full value wind) We are holding off 4 MOA Right wind to compensate for the wind drift. We are shooting the bullet into the wind so that it will bring it back to where we want it to impact.
Should the wind speed change and the shooter not realize, this is what would happen assuming the wind direction does not change. The effects are further accentuated if the wind direction changes.
- 5mph wind – miss, shot would hit in front of the animal. (over compensate)
- 7mph wind – maybe a miss or barely hit (over compensated)
- 10mph wind – shot impacts exactly as shown below right in the lungs. (correct)
- 15mph wind – gut shot (under compensated)
- b) Scenario B – 10mph wind from 3 o’clock with an animal facing away from the wind.
In order to hold 4MOA of Right Wind, we are aiming at his hind legs. Again we are pushing the bullet into the wind so that the wind brings it back to where we want it to impact.
- Wind drops to 5mph – Gut shot (over compensate)
- 7mph wind – Gut shot (over compensated)
- 10mph wind – shot impacts exactly as shown above right in the lungs. (correct)
- 15mph wind – Miss (under compensated)
With a 308Winchester, our Right Wind hold is almost the width of the entire animal at 500m.
Holding Off Windage with your 308Winchester
What does holding off look like in real world scenario? While on the range I managed to take this shot. We were not going to shoot the sheep, it’s just to show you what it looks like. The more you hold off, the large the chance for a miss. Here we are holding 6MOA LEFT WIND meaning we are shooting the bullet into the wind so that it would then blow it back on target.
How do Faster cartridges like the 270Win and 7 rem Mag help us?
They basically narrow down the window that you should hold off as well as diminishing the error bracket. If you ever saw a wind plotting sheet on an Fclass score card, you would see something like this. Dots below the targets plotted to show where the bullet impacted when we dialed a specific wind correction.
Above: Notice the dotted lines that I drew up to show where the bullet impacted the target relative to my wind correction for that shot. It also gives me an idea of how much the wind changed and consequently its effect on my bullet over a 20-shot string at 1000yards. In this scenario we went from 4MOA estimate to 8.25 MOA Left wind call. That’s with a 284win shooting a 180grain VLDs at 2910ft/s, same performance of 7 rem mag!
How do you know how much you have to dial? You can work it out, there is a simple formula to get you there.
(Wind in MOA for 10MPH @3o’clock X by wind speed (mph) X wind direction value (0.5, 0.7, 0.85) = Wind Correction
Then you have to shoot and practice on the range to get proficient at that. A few hundred rounds a year done well will get you there.
Instead of holding all that wind, I prefer dialing in that wind component into my windage turret.
In the picture below, the shooter is dialing in 6 MOA RIGHT WIND. In this case he will not have to hold off his Windage. He will hold dead on target- centre mass. This is a learned skill and you have to practice, dial, adjust, shoot till you gain confidence adjusting the turrets with your eyes closed.
I took this picture through my Swarovski ATS 25-50×65 Spotting scope during Europeans while peeping at some of the windage adjustments during a course of fire. This ukrainian shooter had 6MOA on the very flat shooting 300WSM.
Swarovski BTF Elevation and Windage turrets enable you to do just that. Simple and fool proof to work with. I genuinely believe these are some of the best made turrets out there. Easy on, Easy Off. Moreover, these high quality windage turrets on the Swarovski Z8i enable you to dial 4 Mrad Left or 4Mrad Right then they stop turning, you can never get caught one full turn out. Read more about this Swarovski z8i scope which we used on a hunt in the Pyrenees.
After reading this article, will you be switching to another cartridge or will you explore how your own rifle/cartridge/bullet combination can provide you better ballistics? Contact Us with any feedback you may have and signup to our newsletter!