Maybe I’m reading too much into it, but I received a comment on the 6.5mm Creedmoor selection post where a reader implied the recoil comparison numbers couldn’t be trusted because it was hard to believe that the 6.5mm Creedmoor has 50% more mass [compared to the .243 Winchester] and less recoil. To be honest, I hadn’t looked at it that way before. The truth is that does sound too good to be true so I started second guessing my calculations and figured it couldn’t hurt to revisit this topic in a bit more depth.
Full disclosure, I am a 6.5mm Creedmoor (65CM) fan boy. I won’t deny it. I think it’s a fantastic cartridge and have been using it extensively for deer hunting over the past two seasons (and hunting exotics between the deer seasons). Additionally, my experience is that the 6.5CM does feel like it has softer recoil than the other cartridges I compared in my selection process. This subjective opinion has also been shared by several friends and family members (it was echoed unanimously at a get together I blogged about a while back). However, the subjective perception of felt recoil is anecdotal at best which is why I want to revisit those numbers.
Before diving into the calculations, it’s important to understand that not only is “felt recoil” subjective, but it is dependent on the specific firearm. The design of the firearm, how it’s held, and accessories (like recoil pads and muzzle brakes) are all factors that affect what recoil feels like. Thankfully, we can use math and physics to arrive at some recoil numbers that can be used to objectively compare recoil.
Recoil is generally measured three different ways: recoil energy, recoil velocity, and recoil impulse. Recoil energy is the kinetic energy (measured in foot pounds) of the recoil which can be thought of as how hard the firearm pushes back against the shoulder or the hands. Recoil velocity is a measurement of both speed and direction (measured in feet per second) of the recoil which can be thought of as how fast the firearm is pushing against the shoulder or hand. Recoil impulse is a measurement of the recoil impact (measured in pound seconds) which can be thought of how the recoil feels – a higher value indicates a more forceful impact. Combined these values help create a picture of how strong, fast, and sharp the recoil might feel like.
I’m not going to rehash the physics formulas for these calculations (one can search the internet for energy, velocity and impulse formulas if interested). I’m also not going to reuse my spreadsheet. Instead I’m going to use the nifty recoil calculator available at ShootersCalculator.com. There are four variables used as inputs for the recoil calculations, they are the bullet weight, bullet velocity, powder charge weight, and firearm weight. I’m going to pull the bullet weight and velocities from the advertised values on Hornady’s Precision Hunter product line. The powder charge weight will come from the most accurate powder and charge for the given cartridge with the closest projectile weight matching the Hornady data (some of this won’t be exact, but I’ll link and point to the exact data source). For the firearm weight I’m going to use a static 7.2 lbs because that is the weight of my hunting rifle.
Let’s look at some numbers.
| Cartridge | Bullet Weight (gr) | Bullet Velocity (fps) | Powder Charge Weight (gr) | Firearm Weight (lbs) | Recoil Energy (ft-lbs) | Recoil Velocity (fps) | Recoil Impulse (lbs-sec) |
|---|---|---|---|---|---|---|---|
| 243 Win | 90 | 3150 | 43.5 | 7.2 | 11.06 | 9.94 | 2.22 |
| 25-06 Rem | 110 | 3140 | 47.0 | 7.2 | 14.84 | 11.52 | 2.58 |
| 6.5 Creedmoor | 143 | 2700 | 31.5 | 7.2 | 13.02 | 10.79 | 2.41 |
| 270 Win | 145 | 2970 | 49.5 | 7.2 | 20.26 | 13.46 | 3.01 |
| 7mm-08 Rem | 150 | 2770 | 45.5 | 7.2 | 18.21 | 12.76 | 2.86 |
| 308 Win | 178 | 2600 | 39.5 | 7.2 | 19.21 | 13.1 | 2.93 |
| 30-06 Sprg | 178 | 2750 | 62.0 | 7.2 | 28.16 | 15.86 | 3.55 |
| 300 Win Mag | 178 | 2960 | 79.0 | 7.2 | 37.44 | 18.29 | 4.09 |
So what do the numbers say? Well first and foremost, my calculations during my selection process were wrong. At least, when using a static value for the firearm weight. The numbers here indicate that .243 Winchester (243 Win) calculations yield lower recoil values all the way around. This means I need to go update the older 6.5mm selection process post to hopefully avoid misleading other folks should they stumble upon it.
This begs the question, how is that I perceived less recoil on from the 6.5CM when shooting a 243 Win rifle side by side? Remember, I mentioned that felt recoil is subjective and factors such as rifle features come into play? Well, the 6.5CM rifle I used the last time I shot both of those cartridges in the same range session was the hunting rifle which has a recoil pad and a muzzle break. The 243 Win rifle was a Ruger American rifle which weighs a pound less and doesn’t have either a recoil pad or a muzzle break. Let’s run those numbers again with the different rifle weights and see what we get.
| Cartridge | Bullet Weight (gr) | Bullet Velocity (fps) | Powder Charge Weight (gr) | Firearm Weight (lbs) | Recoil Energy (ft-lbs) | Recoil Velocity (fps) | Recoil Impulse (lbs-sec) |
|---|---|---|---|---|---|---|---|
| 243 Win | 90 | 3150 | 43.5 | 6.2 | 12.84 | 11.54 | 2.22 |
| 6.5 Creedmoor | 143 | 2700 | 31.5 | 7.2 | 13.02 | 10.79 | 2.41 |
The updated numbers are interesting. While the energy gap is smaller between the two cartridges (pretty darn close to identical), the recoil velocity of the 243 in the lighter rifle rose above the recoil velocity of the 6.5CM in the heavier rifle. Given the faster recoil velocity of the 243 and the lack of recoil dampening rifle features, I can see why the 243 could be perceived as having more recoil.
Regardless, I still remain a 6.5CM fan boy. Even so, all of these cartridges are fine deer hunting cartridges. And for the record, I, like many others, don’t like being wrong, but appreciate it when folks point it out since it gives me an opportunity to learn and grow (and update older posts with better information).