The 6.5 vs 308 debate is still going strong, with folks on either side of the argument throwing their opinions into the mix…as well as some good-natured piss taking.
The thing is, you know what they say about opinions right? They are like a#%holes…everybody has one.
Some of the information and opinions folks put forward during these debates is based on ACTUAL evidence i.e. fact, while some of the information isn’t. So, this is probably why one of the most common questions I get asked is “should I buy a 6.5 or a .308?”
And the answer…it depends.
It depends on what sort of shooting you are doing i.e. hunting vs. competition and whether you are shooting in known distance, extreme precision events such as Benchrest or F-Class or whether you are a “practical” shooter i.e. you are a hunter or someone who competes in PRS/NRL type competitions.
So, in this article, I want to address the 6.5 vs 308 question from multiple angles such as ballistic performance, recoil, and hit probability. By giving you this information, you can then make an informed decision about whether a 6.5 or 308 will best suit your needs.
Now, before we carry on let me lay down the “ground rules” for this comparison…
To ensure a fair comparison, the ballistic data will be based on Factory Match ammunition, not hand-loads. We all know that by hand loading we can squeeze more performance out of our rifle but the performance increase across the platforms is fairly linear so there is no real benefit in doing so.
Another reason is that a lot of shooters don’t want to hand-load. They just want to be able to buy accurate ammo of the shelf and go and shoot it. So, by using Factory Ammunition for the ballistics data in this comparison they can see what their “real world” results will look like.
Given that I will be using Factory Match Ammo data, I will keep the chambering/cartridge selection to those that have a good selection of Factory Match Ammo and are those usually subject to the 6.5 vs 308 debate, namely the .308 Winchester and the 6.5 Creedmoor. For interest’s sake, I’ll also include data for the new kid on the block, the 6.5 PRC.
So, in short, I’ll be avoiding the Wildcats and those factory chambering’s that are absolute barrel burners. Instead, we will be looking at factory chambering’s that are common, have factory match ammunition options, and have similar recoil performance.
So here they are:
- .308 Winchester – MV 2650fps – 175gr. Nosler RDF Projectile (Litz G7 BC of .271), 1:10″ twist.
- 6.5 Creedmoor – MV 2695fps – 147gr. Hornady ELD M Projectile (Litz G7 BC of .315), 1:8″ twist.
- 6.5 PRC – MV 2910fps – 147gr. Hornady ELD M Projectile (Litz G7 BC of .315), 1:8″ twist.
Now…let’s get stuck into this 6.5 vs 308 comparison.
6.5 vs 308 Trajectory Comparison:
When shooting “long range”, if range uncertainty exists, then a flat trajectory is important.
If you know the range +/- 1m (i.e. you are using a laser range finder) then a flat trajectory isn’t nearly as important.
Personally, I always favor a flat trajectory because if my laser range finder stops working for whatever reason and I have to use another (less accurate) range estimation method, then I have a higher hit probability with the flatter trajectory due to the increased Danger Space.
Right so, let’s look at the trajectory data…
If you take a look at the trajectory data out to 1000m it is clear that both the 6.5 Creedmoor and the 6.5 PRC outperform the .308, having flatter trajectories.
At 1000m the .308 requires 12.41 MIL of elevation to hit the target. The 6.5 Creedmoor only requires 10.5 and the 6.5 PRC has an even flatter trajectory requiring only 8.74 MILs of elevation!
So…the 6.5 offerings beat the .308 hands down in terms of trajectory.
Ranked in order of performance we have:
- 6.5 PRC
- 6.5 Creedmoor
- .308 Winchester
Next up, let look at wind deflection.
Wind Deflection:
Quite frankly, the wind is every long-range shooter’s nemesis and it results in the most significant reduction in hit probability at long range.
So, choosing a bullet/chambering that “bucks the wind” will improve your hit probability which is a good thing! : )
This is even more important when shooting in topographically challenging environments.
On a nice flat range, making an accurate wind call is often a lot easier than making an accurate wind call in the “real world” where you are shooting in an environment where there are gullies, natural and man-made features that channel the wind in different directions and at different speeds, etc.
So, a bullet/chambering the “bucks the wind” gives us a big advantage.
Now let’s look at how the cartridges stack up…
As you can see, the 6.5 offerings once again outperform the .308 Winchester.
In a 10mph, full value wind, the .308 requires 3.37 MILs of Windage to hit the target at 1000 m. The 6.5 Creedmoor and the 6.5 PRC require a whole lot less, 2.59 MILs and 2.24 MILs respectively.
That means that in challenging wind conditions, the 6.5 offering trump the .308 Winchester.
Ranked in order of performance we have:
- 6.5 PRC
- 6.5 Creedmoor
- .308 Winchester
Next up, let look at retained energy…
Retained Energy:
Now, if you are a competition shooter who is simply punching holes in paper or ringing steel then the retained energy “downrange” probably isn’t a big deal.
However, if you are a hunter, retained energy and retained velocity (next up) are important factors.
So, let’s see how our cartridges stack up against one another.
Am I boring you yet? : )
Yes, the 6.5 Creedmoor and 6.5 PRC once again outperform the .308 (yawn).
By 1000m the 175gr. projectile, having been fired from the .308 Winchester only has 490 ft.lbs of energy remaining. The 6.5 Creedmoor’s smaller 147gr. projectile on the other hand still has 567 ft.lbs. of energy and the 6.5 PRC has even more, coming in at 720 ft.lbs. of retained energy!
Those are impressive figures for the 6.5 crowd.
As always, shot placement is crucial if engaging live targets, however, knowing that you have plenty of retained energy (and velocity) on tap definitely gives you peace of mind.
So, based on the data, and ranked in order of performance we have (no surprises):
- 6.5 PRC
- 6.5 Creedmoor
- .308 Winchester
Next up we will look at another metric which is of great importance to hunters, in particular, retained velocity.
Retained Velocity:
Once again, if you are a competition shooter who is simply punching holes in paper or ringing steel then the “downrange” retained velocity of your round probably isn’t a big deal.
However, if you are a hunter, retained velocity is an important factor.
Remember, we are shooting the ELD M projectiles which Hornady claim delivers sufficient expansion (and therefore terminal performance) at speeds as low as 1600fps.
So, let’s see how our cartridges stack up against one another using 1600fps as the benchmark.
Sorry .308 shooters but once again, both of the 6.5 cartridges outperform the .308 Winchester.
As you can see, the .308 Winchester firing the 175gr. projectile only gets to around 600m-650m before the retain velocity drops to 1600fps.
By comparison, the 6.5 Creedmoor doesn’t drop to 1600fps until between 750m – 800m.
The 6.5 PRC takes things to the next level. Fires from the 6.5 PRC, the 147gr. ELD M projectile doesn’t slow to 1600fps until between 900m – 950m!
Now let’s be clear…just because the bullet is still capable of expanding and having the desired terminal effect at this range doesn’t mean I advocate doing so. I’ll explain more in the next section on hit probability.
So, based on the data, and ranked in order of performance we have:
- 6.5 PRC
- 6.5 Creedmoor
- .308 Winchester
So, what does all this data mean?
Well, it all affects hit probability at long range so let’s quickly look at that.
Hit Probability:
Achieving a FIRST ROUND hit at long range is a real challenge and it is the challenge that faces all hunters who like to push themselves and their equipment to the limit by taking game at distance.
In many other long-range scenarios and/or competitions the shooter either has the opportunity to fire “sighters”, or they are not shooting at a “live” target where the risk of wounding is ever present if they get it wrong.
In these situations, one can afford to miss by a little (usually due to wind), and then simply make a quick correction to get the second round on target.
Hunters tough need a FIRST ROUND hit and it needs to be in the “kill zone” not just anywhere in the body.
So, let’s look at hit probability in a “real world” hunting type situation…
To calculate Hit Probability I have run a 1000 shot simulation using the (awesome) Applied Ballistics Analytics software.
Below are some of the inputs I used for the simulation…
- To “simulate” factory ammunition the SD was entered as 15 fps.
- The wind call accuracy was +/- 2 mph which I think is fair in “real world” situations.
- The rifle/shooter grouping capacity was set at 1 MOA which I think is fair in “real world” conditions i.e. not prone on a flat range. So, maintaining 1 MOA or better whether shooting from the prone, sitting, kneeling or some other alternative position.
- The target size was 10″ (5″ radius) to simulate the kill zone of a medium sized deer.
- I used 500m as the target distance. For many hunters, that is further than they would ever try to harvest an animal. For others, they wouldn’t think twice.
In my opinion, you can take game at any distance you want but you MUST know your limitations which is why I have included this section on hit probability.
So, let’s look at the results…
The hit probability for a FIRST ROUND HIT with the 308 at 500m on a 10″ “kill zone” is only 62.2%
The hit probability for a FIRST ROUND HIT with the 6.5 Creedmoor at 500m on a 10″ “kill zone” is a little over 10% higher at 72.6%.
Finally, the hit probability for a FIRST ROUND HIT with the 6.5 PRC at 500m on a 10″ “kill zone” is 78.1%
So, based on the data, and ranked in order of performance, this is how they stack up:
- 6.5 PRC
- 6.5 Creedmoor
- .308 Winchester
The thing that is hurting us here is the wind. If we can get our wind call to within +/- 1 mph our HP goes up considerably but is that a realistic expectation in the “real world”?
Really, that comes down to the shooter and their ability. Not only to maintain 1 MOA or better from any position but most importantly, to be very accurate with their wind call.
If there is any doubt, get closer!
Don’t risk wounding an animal on account of your ego.
That said, if you are VERY confident that you can make a clean kill beyond that kind of distance, then, by all means, go for it!
In my opinion, the shooter and only the shooter can determine their capabilities. They just need to be honest with themselves and not let ego drive their decision to shoot.
Now, I’ve taken us off track a little so let’s get back on it…
Based on all of the data thus far, the 6.5 PRC clearly dominates the others ballistically but at what cost? Is there a penalty for all this performance?
In short, yes. These penalties come in the form of recoil and barrel life.
Let’s look at the recoil figures first…
Recoil Comparison:
Recoil is worth considering as it can affect our ability to spot hits and/or misses which is really important.
Another important consideration is that generally, the more significant the recoil levels are, the harder it is to maintain that 1 MOA grouping capacity from “field positions”, especially with the ever popular lightweight hunting rifles.
So, let’s look at the recoil figures for the contenders based on a 9 lb. rifle.
Why 9 lbs. you ask?
Why not?
I think it is a reasonable “middle ground” occupied by some good entry level factory rifles such as the Bergara HMR (Hunting Match Rifle) and with the Ruger RPR coming in at around 10 lbs.
The heavier the rifle, the less recoil you have to deal with. The lighter the rifle, the more recoil you have to deal with.
So, if your rifle is heavier or lighter than 9 lbs. you can mentally note that the recoil figures I give you will be a little higher or lower.
FYI, I used the JBM Recoil Calculator to get these figures. For the powder charge weight, I used the figures from the respective reloading manuals.
So, let’s look at the recoil figures…
The recoil value for the .308 came out at 14.6 ft.lbs. The 6.5 Creedmoor is softer shooting at only 11.3 ft.lbs. The recoil of 6.5 PRC, on the other hand, is only slightly more than the .308 Winchester.
If we look at the recoil figures alone the 6.5 Creedmoor wins, the .308 slides into second place, and the 6.5 PRC is relegated to third, although not by much.
On the face of it, the 6.5 PRC is the worst performer but you must remember that for recoil figures that are only slightly more than the .308 you are getting a significant ballistic advantage.
So, keep that in mind.
So, based on the data, and looking at recoil performance ONLY, this is how they stack up:
- 6.5 Creedmoor
- .308 Winchester
- 6.5 PRC
Next up, let’s look at barrel life.
Barrel life:
This one is difficult because there are SOOOOO many factors at play.
For instance, the quality and consistency of the steel used to manufacture the barrel will play a part.
The frequency of the shots being fired also play a part on barrel wear.
A hunter is likely to fire only one or two rounds and so the barrel never gets “hot”. In a competition environment, a shooter may be required to fire a string of 10 to 20 shots fairly rapidly. This WILL make the barrel hot and cause it to wear at a faster rate.
Another factor is at which point is a barrel considered to be “worn out”?
For Benchrest and F-Class shooters, it may be as soon as accuracy drops below .25MOA whereas for a “practical” shooter where 1 MOA or less is all that is required, then they may not change their barrel until the accuracy of the rifle drops close to 1 MOA.
So, for all the reasons above (and others such as cartridge case design), determining actual “barrel life” is impossible.
That said, here are some “general” guidelines around influencing factors…
- The larger the powder charge compared to the bore diameter, the more wear one can expect.
- The hotter the barrel gets as a result of “strings” of fire, the more wear one can expect.
- If the case has a steep shoulder and a short neck, it is likely that the throat will erode faster than a case that has a more gentle shoulder angle and a longer neck.
Based on these guidelines/influencing factors we can make the assumption that…
The .308 Winchester will have the longest barrel life, followed by the 6.5 Creedmoor, with the 6.5 PRC having the worse performance when it comes to barrel life.
So, depending on how often you shoot, how fast you shoot, and what level of accuracy you require, and the case design, will ultimately determine when your barrel needs to be replaced.
Does it really matter…that’s your decision.
So, based on the data, and looking at barrel life ONLY, this is how they stack up:
- .308 Winchester
- 6.5 Creedmoor
- 6.5 PRC
Now I think it’s time to wrap this up…
Conclusion:
As I said right at the start, one of the most common questions I get relates to the 6.5 vs 308 debate, specifically, should I buy a 6.5 or a .308?
Hopefully, I’ve given you enough information here that you can make your own mind up based on the data.
Now, based on the aforementioned data you may think that the .308 Winchester is no longer relevant. I disagree.
Sure, it’s not the best cartridge…but it does “enough” to keep many punters happy. Not everybody feels the need for “blistering” performance.
The .308 has great factory loads and works well even from a short barrel which is ideal for hunting in close country and bush. I like to think of the .308 as a “jack of all trades, master of none” type cartridge.
One other thing that I like about the .308 is the fact that it DOES suffer significantly from wind deflection.
This makes it a great training tools for reading the wind. If you master the wind shooting a .308, when you jump behind a rifle with 6.5 levels of ballistic performance, making hit’s in the wind a much easier.
Food for thought…
A penny for your thoughts:
I’d love to get your opinion on the 6.5 vs 308 debate so leave a comment below detailing which you prefer and why.
Right so, that brings us to the end of this article but before I go, I have a favor to ask of you.
If you found this information helpful, please SHARE it with others.
That’s it from me, take care.
Jeremy
P.S. Don’t forget to take a look at our other resources…
