7mm Rem Mag vs .308 Winchester: Ballistics, Drop & Wind Drift

Magnum vs non-magnum hunting cartridge.

Let’s find out more

7mm Rem Mag vs .308 Winchester: Standard or Magnum?

Are you caught up between a 7mm mag vs keeping your 308win? These are two cartridges that have stood the test of time especially amongst hunters and the rifle community at large. The 308win probably being one of the first cartridges that many shooters picked up at some point perhaps due to the large number of rifles chambered in it, a natural choice for their first rifle. Some even go as far as to call the 308win, the only rifle you’ll ever need.  

Above: Surgeon rifles built for field use, training and the occasional hunt topped with a March 2.5-25×42. Join the March Scopes Facebook group. Most target shooting clubs and ranges start off new shooters on club guns chambered in 308win. This was the case for me having started with a 308win target rifle with a club before building my own FTR rifle in 308win. This was built on a Surgeon XL action with a 308bolt face topped off with a Nightforce 8-32×56 and later adding the Barrett BORS. It shot fantastically well and regret selling it although it was a little too heavy and I have since opted for a lighter 308win, also on a Surgeon action, they’re awesome field-use actions.

Naturally the cartridge you try first tends to leave a special memory, your first bull’s eye, your first plate hit, the first perfect score, 1st game animal shot with it and so it rolls into our shooting history and DNA. If you’re making up your mind about factory vs custom rifle, check out this post here. Our 308Win handload basically replicates the Eldx 178gr load. Through our ladder testing we actually found out this to be the best 308win load in < 50 rounds. The huge variety of 308Win ammo means we can all keep our trigger time urge relatively happy. Depending where you are in the world these can go from €0.50 to €2.50 a pop. You will also find 308win ammo everywhere in the world. It’s not always the same for other popular hunting cartridges. 308Win is also a good rifle to learn wind reading with. Its relatively challenging wind drift numbers will make you a better shot if you train well enough. Checkout what a well-tuned 308win will do in this clip below. We took this rifle out for some load testing at 600m than proceeded to true our kestrel ballistics with actual live firing to make sure it’s dead on for an upcoming hunt in the Spanish mountains.

7mm Rem Mag: What Does the Magnum Offer?

We have found the Precision Hunter Line from Hornady very consistent at long distance. Those that have had a hunting buddy on the magnum side of life was probably running a 7mm mag. You shoot a few rounds with one, maybe take a longer shot than usual with a 7mm mag which has been well setup and the bug is set! You will easily be drawn into believing this is the next big thing up your alley. You search online for answers, join a few 7rem mag groups and by that time you’re believing this is the answer to your hunting needs. That’s how it rolls somehow right? The numerous hunting rifles chambered for it means its accessible off the shelf, so before you know, it becomes your next hunting rifle. All the major ammunition manufacturers make hunting ammo for it and it’s relatively accessible too.

7mm Rem Mag vs .308 Winchester Ballistics and Bullet Drop

The proof is in the pudding or rather in the shooting. Ok so how much better is a 7mm mag to the 308win? I prefer a data driven approach so here’s some drop data to start with. Above you can see the drop in MOA for the two cartridges. Drop does not worry me as much, at longer distance we’ll be dialing in our correction anyhow for an accurate shot or if you have one of the newer Christmas-tree like reticles, you will be able to accurately hold the correction. Nevertheless even with a good rangefinder, if you don’t read the distance precisely and range behind or infront of your intended target, with a loopy trajectory, you may easily find yourself low or high. At 700m, a 308win load as described above will drop a further 7 inches from 700-710m! Above: March 5-40×56 FML reticle with 1 mil increments on windage and elevation enables precise hold if you so prefer. The other reticle shows the FMA-2 an MOA based reticle with 1 MOA increments. Read the full story about this hunt in the mountains We will be using a laser range finder to get the exact range readings as well so no guess work here. Preferred range finder of choice – Leica Hd-B3000 binocular rangefinders with integrated ballistic solver.

7mm Rem Mag vs .308 Winchester Wind Drift

Wind drift is everything. Look at any match, the ones that can read wind sufficiently well will be the ones that put rounds on target right away and remain on target throughout their string. What advantage does the 7mm mag bring to the wind-game? Let’s take a look below. The yellow arrow shows wind component from 3 o’clock (full value wind) as the bullet travels towards its target. Above you can see the difference in windage between a 7mm mag shooting a 162eldx at 2940ft/s (Hornady Precision Hunter load) and a 308win shooting a 178eldx at 2600ft/s (Hornady Precision Hunter load) assuming a 10mph wind full value.  At 600m, the 308win is drifting 3.5” laterally for every 1 mph of wind while the 7 mm mag is drifting 2.5” for every 1 mph wind. That’s an inch extra for every 1mph wind. Keep in mind that at that distance, you are not moving a 1inch group with your hunting rifle but a clay pigeon sized group if you have a well put together setup. This in itself is probably the size of the kill zone. Now add the wind component and you’ll start understand how difficult that shot can be when you have only one round to make it count. I’m not making a case whether to make that shot or not. My goal here is to understand what one cartridge brings to the table compared to the other while helping others understand what are the factors at play. Below, two loads shot at 600m with a 308Win while load testing. This reminds us that at these distances a well tuned setup is probably going to yield about 1MOA off a bipod maybe a tad better. Still the challenge remains there. *They are at different elevation as we didn’t want the two groups to overlap. More about load testing for 308win here. Ultimately you need to dial or hold this correction on your reticle. Most shooters even experienced ones are somewhat flying blind when you remove the wind flags which many competent competition shooters learn to read with high proficiency. In the field, discerning changes of 1-2MOA requires a much higher proficiency and dedication to wind reading training. Most shooters and hunters simply don’t spend enough time on the ranges training for these longer shots. _______________ Learn about the ultimate precision hand made rifle builders from Austria that can build a hunting rifle as precise as a target gun with remarkable work of art embellishing it.

JOHANN FANZOJ 338 LAPUA MAGNUM ‘KIPPLAUF’

How Much Advantage Does a Magnum Cartridge Give?

To give you a practical example, in March 2021, we held the training weekend of Extreme Shot One Mile Italia, a long range shooting competition from 300m to 1640m that will be held on 22-26 September in Sicily. Most shooters here were shooting 338Lapua, a known long distance round. From 14 shooters present, only 2 hit the 400m 3inch plate with their competition rifles and only 1/3 had first round hits at 680m target (40x40cm/16inch) in a competition timed environment. Pressure, time and adrenaline induce errors. The 680m target is shown below. Picture taken on 30x mag. How forgiving is the 7mm mag vs 308? Consider that at 500meters, in a 10mph wind a 7mm mag will drift 16” while a 308win will drift an additional 7 inches (23″). Consider you often get wind gusts or let offs and you may have a hard time making your first shot in that 6 inch boiler room unless you really practice. Above: Not a surprise, during our hunt in the mountains, we encounter a French hunter sporting a Blaser R8 in 7 Rem mag! Smart choice. I took two friends of mine on a training weekend before a European hunt in the mountains. We spent 3 days going through the basics, wind reading, spotting and follow through with relatively good overall performance. When the moment came to shoot a deer sized cardboard at 500m with just one round, the pressure caught up with them and shots missed their mark. They were shooting a 30-06 and a 6.5creedmoor.

Beyond 7mm Rem Mag: Introducing the .300 Norma Magnum

During the training weekend mentioned above, I gave these two hunters the possibility of trying a ‘super magnum’. A 300 Norma Magnum loaded with 215 Bergers at 3250ft/s. That leaves the 7mm rem mag and the 300win mag in the dust bin! Check out their experience with this RPA built rifle and learn more about the capabilities of this superb 300NM, one mile cartridge. _____________________________ Related articles that may interest you.

High Performance hunting magnum

Learn what Ammon Ammon 75 had to say about the 338Lapua as a hunting round in this Exclusive Interview with the record breaking hunter. The view through the March scope 5-40x56___________________________ Blaser makes a hunting weight rifle in this caliber, the 300 Norma R8.

7mm Rem Mag vs .308 Winchester: Is It Worth Upgrading?

The ultimate decision is yours. If longer shots are what you will be encountering as with our hunt in the mountains, a 7 mm mag may just be your ticket to happiness or the precursor before you get sucked on to another magnum! Which ever way you take, it will be a fun and engaging journey. I hope the above article has been of interest to you in finding out some of the differences between a 7mm mag vs 308 and whether it’s worth the upgrade for your needs. Feel free to share your experience below.