Deer Hunting with .220 Swift, 6mm ARC, or .25-06 Remington?

A reader asked for a comparison between the .220 Swift, 6mm ARC, and .25-06 Remington cartridges with a deer hunting context. Of course, comparing cartridges is something that I enjoy and, as such, I’m happy to oblige.

Before getting started, I want to be clear that I don’t have any direct experience with .220 Swift or .25-06 Remington. I’ve also only started dabbling with 6mm ARC. As such, this post will be purely academic and I’ll consider the external and terminal ballistics of these cartridges using advertised ballistic data. In other words, take what I say in this post with a grain of salt.

One more thing before getting into the nerdy details. As previously covered, deer are classified as medium game animals (CXP2). For this class of animal, I’m looking for 800 ft-lbs of impact energy and a projectile with a .210 sectional density (SD) or greater to ensure sufficient penetration and terminal energy in order to ethically dispatch a game animal of this size. The .210 SD requirement is a problem for .220 Swift since even the heaviest 62gr 22 caliber (.224″ diameter) projectiles the cartridge can be loaded with only provide a .176 SD. In my opinion, this makes the .220 Swift suitable for varmint and predator (CXP1) hunting, but not suitable for medium game animal (CXP2) class. For the sake of this post, I’ll ignore that detail for the comparison.

Enough preamble, let’s look at the ballistic properties of the cartridges I’ll be comparing.

At first glance, the ballistic data supports the notion that the 6mm ARC and the .25-06 Remington with the loaded projectiles have the properties I would look for in a deer hunting cartridge.

The initial muzzle velocity and energy from the .220 Swift are quite impressive. If it wasn’t for the low SD, then I’d say it is also a viable deer hunting cartridge. That said, the .220 Swift’s numbers make it look like a .223 Remington on steroids. I’ve also heard several anecdotal stories of folks successfully harvesting deer with a .223 Remington. As I’ve mentioned, it wouldn’t be my choice due to the SD I demand for a deer hunting cartridge of this caliber. However, I’m sure other folks will disagree on that point. The question that remains is how far can it go and retain more than 800 ft-lbs of energy. Given it has a much lower BC than the other two cartridges and the lowest muzzle energy, we can expect to have the shortest range of the three.

The greater velocity and muzzle energy of the .25-06 Remington seems to suggest that it will have the longest range of the three cartridges. However, it does have a lower BC than the 6mm ARC which means the .25-06 Remington will decelerate and lose energy faster than the 6mm ARC. The only way to be certain of the deer hunting effective range is to put the ballistic data in a ballistic calculator and see how these cartridges can go before their energy drops below 800 ft-lbs. Let’s do that now.

As predicted, the .25-06 Remington had the longest effective range out of the batch with an effective distance of 725 yards. The 6mm ARC came in second place with an effective distance of 550 yards. The .220 Swift’s effective distance came in at 275 yards. Once again, the .220 Swift reminds me of a .223 Remington on steroids as the .223 Remington can only maintain 800 ft-lbs of energy out to about 175 yards.

Before I close out this post, let’s compare the drop and wind drift from these cartridges at those same distances to get an idea how flat they shoot.

At 275 yards, the .220 Swift is the flattest shooting cartridge so far with -6.4″ of drop. This might seem contradictory given it had the lowest ballistic coefficient which describes how “aerodynamic” the projectile is; the higher the value the more “aerodynamic” the projectile is. However, the .220 Swift was also the fastest projectile out of the muzzle by large margin. This means that if all three cartridges were shot at the same time, the .220 Swift would have been the first to reach a target at 275 yards. This also means that gravity had more time to do it’s thing before the 6mm ARC and the .25-06 Remington reached their 275 yard targets.

At 550 yards, the .25-06 Remington is also traveling faster than the 6mm ARC. This makes the .25-06 Remington the second flattest shooting cartridge of the batch. Much like the .220 Swift, the faster muzzle velocity of the .25-06 Remington was enough to make up for the slightly lower BC difference compared with the 6mm ARC.

What about wind drift? Let’s check it out.

The large BC difference between the .220 Swift and the other two cartridges becomes apparent when looking at the wind drift these cartridges experience at 275 yards given a consistent 10 MPH crosswind to contend with. At this distance, the .220 Swift drifts 8.8″ compared to the 5.1″ drift of the 6mm ARC and the 4.8″ drift of the .25-06 Remington.

Similarly to what we witnessed when comparing drop, the greater initial muzzle velocity of the .25-06 Remington is enough to make up for the difference in BC value compared to the 6mm ARC.

So there you have it, a brief comparison of these three cartridges with the context of deer hunting. As I wrote this comparison, I became increasingly intrigued in how they would compare in the context of varmint (CXP1) class and predator (CXP1) class contexts. That might be a fun exercise. Let me know if that is something you would like to see.