A study on the 308 Winchester:
As an introduction, In this piece we will attempt to showcase that different factors will give an edge to a certain type of load combination. This is not an exhaustive work and therefore is not a complete catalogue on the 308 Winchester. Instead, it is an attempt to maximize a desired outcome from different types of rifles. This work will explain our observations, which are subjective.
After over 5,000 rounds loaded, hundreds of load combinations tested and fired for competitions and game harvesting, we have made these observations as to applying the correct type of load in the correct type of rifle to maximize the desired outcome.
We will break the rifle categories down into 5 basic groups:
- Bolt gun with long barrel
- Bolt gun with short barrel
- Gas gun with long barrel
- Gas gun with short barrel
- Pistol length barrels
For clarification we will use the length of 20 inches as the dividing line. Less than 20 inches will be considered a short barrel. 20 inches or longer is considered a long barrel. This is subjective and could be argued. The reason we chose 20 inches as the dividing line came from our chronograph work. As a general rule, a 24 inch barrel shot 100 feet per second faster than a 20 inch barrel and a 16 inch barrel was 100 feet per second slower than the 20 inch tube. It seemed reasonable to make the division at 20 inches.
Bolt guns classification This includes non self-reciprocating actions so things like break actions, falling block, rolling block, etcetera qualify while Gas Gun classification have self-reciprocating actions; M14/21, HK or clones, FN FAL or similar, AR-10, LR-308, Remington 740 and similar, etcetera.
All firearms used in testing were privately owned. Some were factory original and some were highly modified and specialized. We used rifles from Aero, Rock River, Remington, Ruger, Savage, Tikka, Sako, Springfield Armory, Mauser, POF, SIG, FN, Winchester and a couple of custom actions.
When I use the term “we” in this writing it is because this information has been gathered from several users. I have personally loaded over 4,000 rounds of 308 Winchester for this test while other contributors have loaded extensively as well as using factory rounds.
Please understand that this was not something that we set out to do. There was no pre-planning and no expectation of compiling data. All of this testing came about from our curiosity. Instead of a project it is more of a musing about what we have learned over the years. Speaking of years, let me take you back to where this all began for me.
It was 1996 and I was in high school. A Remington Sendaro with a 26” fluted barrel had caught my fancy and I made her mine. What a piece of machinery! I had fallen in love with the 308.
It was everything I had wanted and dreamed about. Her accuracy was amazing, rivaling many custom guns. She was smooth, fast and sweet; until I took her hunting in the thickets of my Eastern Tennessee woodlands. It was there that my dreams of lifelong happiness with my new love were broken. Lugging that crazy rifle through the woods was a nightmare. I sold it to a friend who has owned her ever since.
After graduating from college I moved back to Tennessee and purchased another 308 in a Sako. That old girl had it all. She was light, fast, accurate, easy to handle and deadly in the woods, but she was certainly not easy on the shoulder. She kicked so badly that even with 150 grain bullets my Wife would not shoot the rifle. It seemed the 308 had let me down again. I wanted it to be THE cartridge. It had all the potential and it was certainly plentiful so it just made sense that it could be the one cartridge that does it all. But, unfortunately, it was not. Yet. Or more precisely, my experience was lacking for me to get the big picture.
There is more to this story, the Sako was built in the late 60’s or early 70’s I honestly don’t remember if it was a pre-Garcia or not. It was beautiful and I did not have the heart to have a muzzle device added to that gorgeous blued barrel. This rifle was my first real foray into long range. We learned in 2003-04 that hitting milk jugs at 800 yards was possible with a factory 308 using Remington 165 corelokt and an 80’s era 3-9 Leupold with a duplex reticle. After some practice 600 yards was easy and 800 yards could be done on a windy day using a sighter round.
A decade passed as did my rifle collection and I found myself drawn again to the 308. This time it was for my Son. He wanted a rifle that would be a good hunting rifle but could also be accurate. Wanting to shoot in competitions for fun and practice with his hunting rifle motivated the hunger for change. He was currently using a 6.5 Grendel and was unhappy with it as ammunition and bullet selection made his particular rifle hard to find a load for. I assumed he would be choosing the new kid on the block, one of the Creedmoor’s, and was surprised when he purchased the 308. He felt the 308 would be better on game and offer a wider selection of factory ammo and hand loading options. He ended up taking a deer with that rifle at around 7 yards. Not exactly what he was expecting but it worked well.
Now that my love affair with the 308 had come full circle and my Son was in love with it as well, I revisited the loading manuals and plied the accrued knowledge of tinkering with loads that the years had granted. Having almost 40 years of reloading under my belt, I now knew that I could tailor loads to fit situational needs and the rifle/platform was simply a tool which could be maximized by the loading choices.
At this point I started keeping track of our loads and we are now well over 4,000 rounds hand loaded. Most of them in batches of 5 for initial testing and then in batches of 10 for confirmation testing. This was not all about accuracy and precision of the loads. We have found some fairly universally accurate loads that seem to function well in almost every rifle. We also found that with changing the seating depth we can influence group sizes for a specific rifle. In other words- we choose a projectile for the specific rifle and intended purpose then choose a powder which will achieve the speed needed to do the job then adjust the seating depth as necessary to get the desired accuracy potential. I am sure many will argue with this process but I can tell you it works for our purposes of creating reliable and repeatable minute of angle groups. We attempt either 3-3 shot groups or 2-5 shot groups, depending on the platform we intend to use, to verify consistency.
Before we jump into the comparison section, allow me to implement a system to qualify the differences.
For comparison standards parameters need to be established. To simplify parameters we will employ distance as the primary differentiating factor. Then we compared drop, drift and foot pounds of energy as secondary factors to determine how each projectile performs at specific distance based on cartridge and firearm capabilities.
Note: as this is THE SECOND MOST IMPORTANT FACTOR in our parameters, allow me a moment to explain wind drift. Wind deflection, wind drift, horizontal shift or whatever else you want to call it, comes from environmentals changing (as in wind speed, angle, switching winds, etcetera) we have noticed in our testing this is determined by time of flight all other factors being equal. For instance- a projectile with a .545 G1 BC going 2450fps (16” 308) will have a much larger wind drift than the same projectile going 3150 fps (26” 300 Win Mag) this is why the 6mm rounds dominate so many shooting disciplines and why the 6.5 Creed is so much “better” than the 308. They can push a bullet with similar BC at a speed commensurate to or faster than the 308 with less recoil. However, what the 308 lacks in specialization it makes up for in versatility. A 308 gas gun with a 16” tube can be supersonic past 1100 yards and at 1500 yards still has over 500ftlbs of energy and has about 2.4 Mils of wind drift.
To be fair, that wind drift is not too much different than the 6 Creedmoor fired in a 16” gas gun but the 308 has a little over 2 times the foot pounds of energy… because the bullet weighs a little over twice as much.
Parameters than can cause deviations from average.
1- distance
2- projectile capability as in ballistic coefficients, sectional density, weight, form factor and then bullet modifications such as coatings, tipping or nose ring, etcetera can be employed as well.
3- cartridge and variations. For example: large rifle primer vs small rifle primer, Military brass versus commercial, brand of brass, steel or alloy.
4- rifle configuration as in barrel length, twist rate, action type and so on.
For instance- When we compare a 6.5 Creedmoor to a 308 Winchester we will need to be specific about all of the above factors to be concise in the comparison.
For example, at 100 yards most commercially available full power load and rifle barrel lengths will produce drop, drag and wind drift numbers similar enough to merit little if any differentiation between the two cartridges but at 800 yards there can be more than a 30% difference in a 24” Creedmoor and a 16” 308 in wind drift even when similar ballistic coefficient projectiles are employed because the speed difference allows the Creedmoor to have less time of flight producing less deviation.
Let’s get into the divisions:
- A bolt rifle with long barrel. Having used rifles from 20” up to 26” please let me reiterate this information is a generalization and is made using a broad interpretation.)
This division is generally considered to be the most effective section; mainly because the length of barrel and lack of gas system provide the peak pressure availability from the round. This translates into higher velocities which provides better exterior and terminal ballistic performance. In short, it goes faster, hits harder and kills better.
0-300 yards.
If you are shooting or hunting Whitetail at distances inside 300 yards this category gives you the most freedom for ammunition choice. We have used almost every bullet weight from 120 up to 230 with success. Typically, the sweet spot is, as expected, in the 150-185 grain range. This will be the sweet spot for this distance in all divisions. Larger game will require the shooter to be more precise about their bullet selection and I personally recommend copper projectiles from 150 and up as well as hunting specific cup and core projectiles in the 150 to 185 range with our best luck coming from what is considered antiquated, an 180 grain flat base lead tipped spitzer.
300-500 yards.
If you are shooting out to 500 yards we have seen exceptional accuracy results on targets with most available bullet weights but the 155-215 grain boat tail designs are superior with the 155- 175 grain range getting the nod most of the time. We did not take many shots on game between 300-500 yards but the tipped projectiles seemed to be superior in the terminal ballistics department at this range.
From 500-800 yards the 155-215 class projectiles are all but essential. Most often the 168-185 selections rule here with the hard to find 195 Sierra TMK being included. Collectively we have only taken a handful of shots on game past 600 yards and I do not have a solid recommendation on what to employ at this range mainly due to needing a “target” bullet to hit at this distance rules out many traditional hunting rounds. Several years ago some companies developed “long range hunting” lines. We tested some and took them hunting. As fate would dictate, we shot the deer at less than 20 yards. Unfortunately, we were never able to recover the animal. It appears the damage was superficial and never reached the vitals. We discontinued the use after that incident.
800-1200 yards narrows the field considerably with the 168 up to 230 weight class is typically needed.
The tried and true 200 grain SMK, the 215 Berger were originally our only available (in stock) options but now there are several new and specialized options. Personally, I’d like to attempt 1200 with some 250 grain Hornady A-Tips but have not yet had that pleasure.
We took some 175/178 grain tipped bullets to a PRS match where they performed beautifully but in all honesty we had some old 180 grain spitzer boat tails with a Balistic Coefficient hovering around .500 that did just as well to 1000 and were fairly stable transonic out to 1200. We were able to hit 50% on the 1200 yard full size torso steel from prone before the match started.
I do not recommend taking hunting shots at these distances. In fact, I do not recommend the average hunter to take shots at 500 yards unless you have earned the confidence with your system to do so reliably.
2. Bolt rifle with a short barrel.
0-300 yards.
This information is the same as the Bolt action with long barrel.
300-500 yards.
The information is similar to the long barrel bolt gun with a few minor exceptions:
Bullets less than 155 work great on targets but most are not designed for deer sized game unless they are machined copper. Most others are designed for varmints and do VERY WELL in that role. The Speer TNT, Hornady V-MAX and others are exceptional at taking varmints out to 500 in short barrels because their time of flight is truncated. When you get to the 500 yard mark the speed reduces quickly and they lose their effectiveness.
Federal sells a 130 grain hollow point that has given great accuracy for factory ammunition and explosive results on varmints.
500-800 yards.
At these distances it usually takes a high BC projectile to be effective. 155 Palma style works well but the 168-185 is typically employed. With a good wind call these rifle/ high BC pill combinations can be highly effective. The good news is there are more than a few factory ammunition selections that make this distance possible. You do not have to employ a custom rifle with specialty ammo to be reliably effective out to 800 yards with a 16” bolt rifle in 308.
800-1200 yards.
This is reaching the end of reliability for a shorter barrel. At 800 yards most projectiles will have about 5 feet of wind drift in a 10 mile an hour cross wind and will be dropping almost 20 feet. In comparison, a 6 Creedmoor with a 24” barrel would have less than 3 feet of wind drift at the same distance. The round is certainly accurate enough to do the job but the environmental variations add up.
We have been successful multiple times at hitting our 1000 yard target with a 16” bolt rig that does not mean we can be reliable with it in poor conditions.
As we were comparing the 308 to the 6 Creed earlier, allow me to point out a 16” 308 is almost exactly 30% more wind drift at 800 yards than a 24” barreled 6.5 Creedmoor with similar balistic coefficient projectiles.
3. A gas gun with a long barrel.
As an important note, when hand loading for gas guns we found the best results in accuracy/reliability matrix when using medium loads as the top end. When we used hotter loads it became increasingly harder to keep the firearm in reliable functioning order. Also, it is ALMOST MANDATORY, whatever that means, to employ adjustable gas systems. Most of our gas guns failed to operate for any length of time with different muzzle devices and suppressors when they did not have an adjustable gas block.
0-300 yards.
This information is the same as the Bolt action with long barrel.
300-500 yards.
This information is very similar to a 16” bolt rig at these distances.
One main exception is that although we have used 175, 180, 185 grain bullets to take game at these distances we recommend the lighter 150-165 grain pills for increased terminal performance.
500-800 yards.
We typically only target shoot at these distances with a long barreled gas gun. We have taken a couple animals in this range but both were less than 600 yards.
To get out to 800 you will usually need a 168-185 long range bullet.
800-1200 yards.
This is pushing the limits on the average shooter and system. I have shot a 1.34 MOA 5 shot group at 1000 with a 20” gas gun using 175 grainers with ballistic tips in a gusting 20 mph wind. When the standard 175 class open tip match was used the Doppler target could only read about 60% of the rounds fired. We have not been able to reliably make impacts past 1000 with any projectiles when there is more than a light breeze blowing.
4. A gas gun with a short barrel.
(This paragraph is the same as the gas system with long barrel) As an important note, when hand loading for gas guns we found the best results in accuracy/reliability matrix when using medium loads as the top end. When we used hotter loads it became increasingly harder to keep the firearm in reliable functioning order. Also, it is ALMOST MANDATORY, whatever that means, to employ adjustable gas systems. Most of our gas guns failed to operate for any length of time with different muzzle devices and suppressors when they did not have an adjustable gas block.
0-300 yards.
This information is the same as the Bolt action with long barrel.
However, it is notable that we were able to build a 9 pound AR-10 with a 16” barrel and an LPVO that was not equal to a 5.56 but close to the manageability of recoil by loading 125 grain bullets at a modest speed. This setup is far more effective at terminal performance than the standard 5.56 at this distance.
300-500 yards
Generally, for hunting varmints we have found 130 grain and down works best in the 16”gas rigs.
For deer we have used the 175/180 grain but recommend the 150-165 grain hunting bullets.
For targets almost any traditional ammo will do well.
Case in point, I took a pistol shooter out to sight in his 16” barreled 308 gasser and within 20 minutes he was ringing steel at 457 yards from a standing tripod. The target was 4” wide and he could reliably (over 80%) hit the target with a 6 power LPVO.
This cartridge is ridiculously effective at reasonable distance for a broad range of applications.
500-800 yards.
Honestly, we found our 16 inch 308 gas’s guns are almost identical at 800 yards as the average 16” 5.56 is at 600… not in the drop and drift numbers but in hit percentage. If you know what you are doing, a good shooter can hit a reasonable target reliably at 800 yards with most high BC target style bullets when they are using an accurate platform, have built a good position and know their DOPE.
We do not recommend hunting at these distances with these rigs.
800-1200 yards.
Hits are possible but not probable when more than a 5mph wind is encountered unless you go with a specialized projectile.
We have used the high BC 230 Berger going about 2100fps and it works. It actually worked better than we thought. The problem we ran into is the gas guns do not function well with heavy bullets. We installed a JP Enterprises Silent Capture spring system that is tunable, in conjunction with an adjustable gas block we could get it to cycle reliably. The whole system had to be specialized to keep it from beating the rifle to death.
5. Pistol length barrels.
These can be VERY accurate in bolt, single shot or gas gun systems. I only have a small amount of information available but I can tell you a 308 in a short barreled rifle or a pistol can be brutal to shoot without a suppressor.
I do not have enough information at distance from target shooting or hunting to go past 300 yards.
At 200 yards these systems can be very accurate and very effective. One friend used a 15” barreled 30-06 to hunt with. He bagged pretty much anything he wanted with it but would not shoot over 150 yards. I asked him why he used a 30-06 instead of a 308. He liked using heavier (180 grain) bullets and it was easier to get them in 30-06. Ballistically, with a 15” barrel the two cartridges were similar and I think the 308 would have worked better if he hand loaded.
For the record, again, 180 grain flat nosed or lead tipped spitzer flat based bullets are UNBELIEVABLY accurate and deadly at modest distance. If your hunt generally ends in a close shot, that old design is effective terminally in every platform that will stabilize them.
As a side note, when loading for 16” barreled gas guns I found the 308 pistol hand loading data valuable.
Closing thoughts:
- Hand loading gives you more options.
- If hunting, it is generally advisable to use a bullet designed for hunting. Many whitetail have been harvested with a 168 SMK. However, when we went hunting in Idaho the Guides discouraged using 308’s because too many animals survived encounters.
- Hunting bullets may not be as accurate as target bullets but if you can shoot close to a 1 MOA group with it you should be fine out to 300 yards.
- If you plan on hunting out to 500 yards you need a reliable Rangefinding tool you are competent with, have verified your information and practiced until you are reliably repeatable.
- I have owned and shot several exotic and wildcat cartridges that I would classify as more accurate than the 308 Winchester. A 6 Dasher or 6BRA, a 6×47 Lapua or a 7SAUM could be said to be very accurate. However, I have seen a factory 308 using factory ammunition cut nylon strings at 200 yards. And I watched as 3 different shooters hit 1/2 paintballs on the first attempt at 100 yards with a factory 308 using factory ammo. It is my firm belief the 308 Winchester, the 6.5 Creedmoor and the 223 Remington are the reasons exotic calibers remain exotic. Very few people need a 7SAUM when the 308 is readily available and modestly priced.
- The 308 Winchester, in my opinion, is THE benchmark by which all other cartridges are judged. For better or worse it is as middle of the road as it gets.
- If you have never used the 308 Win for varminting using varmint bullets, you don’t know what you are missing; It is explosive fun!
- It is my opinion if you could only have 1 rifle you should consider the 30-06 above the 308. But, most of us want more than 1rifle and a 308 is hard to beat.
- The 308 has an amazing range of capabilities that extend into the subsonic realm which make it a more complete package than most cartridges.
- If you want to own a 308 for small framed shooters a muzzle device should be considered.