Load development for a .308

[fordtruckin]

Just started reloading for my Bergara in .308. I decided to use 165gr Accubond's and IMR4064 since I had a pound of it kicking around. I started my test in .5 gr increments starting at 41.5 gr up to 44 gr. After today's run the most accurate 4 shot group was .681 over 42.0 gr. My manual shows that to be on the lower end of the scale for IMR4064. My thought is to do another test of 41.8 42.0 and 42.2 to see if that's the rifles sweet spot and sacrifice speed by going with a lower charge. Or should I try working the higher charges to see if I can get them to tighten up? From the testing I did today the higher charges appear to open up to around 2-3" once I hit 43.0 gr. The tightest groups were 42.0 and then 42.5. I seated the bullets as close to a factory COAL as I can get using a micrometer and the Hornady comparator. I am shooting through a can so I'm not sure if that makes a lot of difference other than a POI shift if I shoot without it on.

Any thoughts as I am far from a master reloader. I'm hoping to get a load figured out and get plenty of practice in before general season starts in MT on October 24th.

[elkhunter11]

0wrsonally, I don"t bother with increment of less than 1/2 grain with a case the size of a 308win. If .2gr makes a significant difference in accuracy, the accuracy will also usually fluctuate with temperature. I look for a load where the accuracy is consistent over at least a full grain or so. I just finished load develop with my 6.5prc, and the accuracy is 1/2 moa over three grains. If I could not get acceptable accuracy with your powder/bullet combination, at a velocity that you are happy with, after experimenting with seating depths, I would try another powder.

[gunluvr]

Can't go wrong with Varget in a .308. It's belongs to Hogdon's Extreme Series which is supposedly less temperature sensitive.

[sns2]

With 165s and IMR 4064 there is typically a sweet spot around 42.8 grains give or take, so you are there.

I will echo the suggestion to try Varget and look for an accuracy node right around 46 grains.

[Dean2]

Add powder till you reached published max or max velocity. Then play with seating depth, mag length and less, seating .005 shorter per batch, to get best group. Now reduce powder charge .3 at a time at best COAL to see if group tightens up. You want max velocity with good accuracy and this method gives me that while burning the least amount of components

[Faststeel]

Originally Posted by Dean2

Add powder till you reached published max or max velocity. Then play with seating depth, mag length and less, seating .005 shorter per batch, to get best group. Now reduce powder charge .3 at a time at best COAL to see if group tightens up. You want max velocity with good accuracy and this method gives me that while burning the least amount of components

I have loaded for almost as many rifles as you dean and I cannot think of a single time that the rifle ever shot best below maximum case capacity.....?

[catnthehat]

Changing the overall cartridge length by .010 can at times have a very dramatic effect .
I start with a mid to upper range powder charge .
I adjust my OAL before my powder charge when working up a load .
I find the most accurate length then start messing with my powder charge .
Cat

[Roamer]

Originally Posted by Dean2

Add powder till you reached published max or max velocity. Then play with seating depth, mag length and less, seating .005 shorter per batch, to get best group. Now reduce powder charge .3 at a time at best COAL to see if group tightens up. You want max velocity with good accuracy and this method gives me that while burning the least amount of components

X2

Most of my rifles do best at max powder charge, I have no problem with that.

[pikergolf]

In my somewhat limited experience, first thing I do is get close to the lands before I start playing with charge weights. I like to start at 15 thousands off the lands. Again I do not have a ton of experience, but I have never had a rifle shoot well until I was close to the lands. How do you find the lands without tools. Here.

https://www.youtube.com/watch?v=TWmIwPwLyyg

[elkhunter11]

Originally Posted by pikergolf

In my somewhat limited experience, first thing I do is get close to the lands before I start playing with charge weights. I like to start at 15 thousands off the lands. Again I do not have a ton of experience, but I have never had a rifle shoot well until I was close to the lands. How do you find the lands without tools. Here.

https://www.youtube.com/watch?v=TWmIwPwLyyg

While close to the lands is where I like to start, it isn't always possible, due to magazine length, or not enough bullet shank in the case neck. And I have had very good accuracy out of several rifles , with quite large jumps to the lands. My Tikka rifles all shot well, and all had large jumps to the lands and my Christensen 6.5prc shoots very well with a large jump, that is required for my loads to fit the magazine.

[catnthehat]

Some of the hunting rifles I shoot run As tight as 1/2 MOA at 200 yards ( 6.5x284)with an .080 jump and these are single shot falling blocks not bolt actions .
My 6MMBr match rifle ( Sportco single shot ) shoots 105 to 108 bullets really well with a .045 jump .
Cat

[kujoseto]

Lots of experience posting above.
I will say that I’ve never concerned myself with chasing the lands as I load for hunting rifles and it needs to fit the mag length anyway.
I typically use the ocw method but have at times started with same cartridge length and change charges or switched to using consistent charge weight with adjusting cartridge length. Reason I prefer to use one length and adjust charge first is I seem to get my end result with fewer rounds fired, which for me means less component consumption and more time on the range for practice. And if you’re like me, that range time can be a challenge to carve out and is precious haha.
Something else I like with changing charges first is I can see the trend of where the group moves and I don’t have to worry about group size yet. Typically I can find 3 consecutive charge weights that group near each other and velocity somewhat plateaus or at least has better extreme spreads. Then I dial the group in playing with seating depth. I think on one occasion I ended up changing primers (read that can be a final factor worth considering) but I usually change the bullet or powder or both if I’m not getting satisfactory results early on after adjusting seating depth (which for me usually means seat near max mag length and seat deeper by 0.010 increments from there)
My view of satisfactory results may be impacted by limited experience, limited range time, and most of all limited patience lol.
If I ever had issues with a specific cartridge, I’d reach out to the likes of elkhunter11, cat, dean, or chuck and take their advice.

[Coiloil37]

Being as you didn’t post a velocity I’m assuming you haven’t got a chrono. As per Nosler that load runs around 2600 from a 24” barrel which is leaving 300 FPS on the table compared to the top performing powders. From my perspective that makes 4064 a non starter unless you just want to make some noise and put holes in paper.
Personally I never had any luck with varget in a .308 but RE15 gave me 2850 FPS from a 165 accubond in a 22” tube.

[Deer_Hunter]

Originally Posted by elkhunter11

While close to the lands is where I like to start, it isn't always possible, due to magazine length, or not enough bullet shank in the case neck. And I have had very good accuracy out of several rifles , with quite large jumps to the lands. My Tikka rifles all shot well, and all had large jumps to the lands and my Christensen 6.5prc shoots very well with a large jump, that is required for my loads to fit the magazine.

I don't have a ton of experience in reloading however some bullets tend to perform better with larger jumps - Barnes in particular recommends beginning at 50 thousands off the lands and potentially walking back further

[DeadEyeGardner]

Originally Posted by catnthehat

Changing the overall cartridge length by .010 can at times have a very dramatic effect .
I start with a mid to upper range powder charge .
I adjust my OAL before my powder charge when working up a load .
I find the most accurate length then start messing with my powder charge .
Cat

This has always been something I’ve tried to wrap my head around. Can you (or anyone else) give me some reasoning behind finding an accurate coal first then playing with charges compared to finding a powder charge that shoots pretty well the fine tuning with coal?

[catnthehat]

Originally Posted by DeadEyeGardner

This has always been something I’ve tried to wrap my head around. Can you (or anyone else) give me some reasoning behind finding an accurate coal first then playing with charges compared to finding a powder charge that shoots pretty well the fine tuning with coal?

The COL will change the barrel harmonics before a powder change will .
This is not anything new or unusual , many long range match shooters and companies like Seirra have advocated if for many, many years .
A powder charge change will change barrel harmonics and group size to z certain extent , and I believe SBR shooters change powder charges regularly , but they shoot ages fixed distance .
It is far easier to develop a truly accurate load from 100 to 500 yards for instance when shooting at the actually distance.
just because a particular load is accurate at a certain distance does not mean it will be accurate at longer distances, and it is much easier and accurate to change the COL ice a cartridge at the bench than it is the powder charge .
Cat

[Dean2]

Originally Posted by DeadEyeGardner

This has always been something I’ve tried to wrap my head around. Can you (or anyone else) give me some reasoning behind finding an accurate coal first then playing with charges compared to finding a powder charge that shoots pretty well the fine tuning with coal?

When trying for the best load you want to play with only one variable at a time. First step, determine max powder load, no pressure signs at max published velocity, with bullet at max mag length that is still at least .010 off the lands. This gets you max load/vel for that rifle and bullet combo. Now by finding the best COAL, working shorter from where you are, you are looking for the very best group at your maximum load and velocity. If you can get the max load to shoot well, 1/2"' to 1" then you have maximized both velocity and accuracy. You can drop powder charge by .3 at a time at the best COAL, best COAL usually doesn't change with velocity much, but most of us for hunting loads aren't looking for the last .2 smaller group size if we have to give up much velocity for it.

You can look for the best charge weight first but the problem with that is if it is near max load and you have to go longer in COAL to fine tune then you risk getting pressure due to less jump to the lands.

P.S. Just saw Cat's post, and he is right about this being the recommended approach by many top shooters as well as at least three of the companies that publish load data. There are a ton of different methods for load development, they all get the job done, pretty much pick your favourite. This is my favourite after years of trail and error, others prefer a different method.

[Pathfinder76]

One thing to keep in mind. Many loads get dismissed because the developer quits at 30 to 50 thou off the lands. I’ve seen many loads turn into “tack drivers” with bullets seated deeper than that.

[Dean2]

Originally Posted by chuck

One thing to keep in mind. Many loads get dismissed because the developer quits at 30 to 50 thou off the lands. I’ve seen many loads turn into “tack drivers” with bullets seated deeper than that.

Agreed. Especially with Barnes bullets I have seen lots that want to be .1 to even . 15 off the lands to shoot their best.

[kujoseto]

Originally Posted by chuck

One thing to keep in mind. Many loads get dismissed because the developer quits at 30 to 50 thou off the lands. I’ve seen many loads turn into “tack drivers” with bullets seated deeper than that.

Very good point.
I have shot several rifles that could not get any closer than double or triple that distance to lands based on mag length and were plenty accurate.

[DeadEyeGardner]

So I’m understanding it as... Start with a set coal about 0.010 off the lands, and work up the powder charge to find a maximum and start seeing pressure signs. Then back off the lands more in small amounts at the max charge weight to see if the group size will tighten up?

BG

[catnthehat]

Originally Posted by DeadEyeGardner

So I’m understanding it as... Start with a set coal about 0.010 off the lands, and work up the powder charge to find a maximum and start seeing pressure signs. Then back off the lands more in small amounts at the max charge weight to see if the group size will tighten up?

BG

.010 is a good place to start .
Remember, it is just a number and one rifle and bullet may not work out the same as another , that is one reason log books are do important .
Personally speaking , I set my cartridge length so it is touching the lands , then load all my test ammo so the bolt will just barely close on a loaded case .
I then start my load testing about .010 off the lands , 5 at a time until I hit a point to where my groups quit closing up or the bolt gets tight on using .
I also check the ammo closer to the lands as well.
One rifle I own shoots very well with Seirra Match Kings right into the lands with less than s caliber of bullet in the case .
Another shoots Verger 107's at .040 off.
These rifles however are true single shot match rifles and will hold a 5 shot group to 1/2 MOA at 1,000 benched and scoped.
For My hunting rifles I set the ammo at least .020 off the lands and sons are as short as .080 off the lands .
Cat

[DeadEyeGardner]

Originally Posted by catnthehat

.010 is a good place to start .
Remember, it is just a number and one rifle and bullet may not work out the same as another , that is one reason log books are do important .
Personally speaking , I set my cartridge length so it is touching the lands , then load all my test ammo so the bolt will just barely close on a loaded case .
I then start my load testing about .010 off the lands , 5 at a time until I hit a point to where my groups quit closing up or the bolt gets tight on using .
I also check the ammo closer to the lands as well.
One rifle I own shoots very well with Seirra Match Kings right into the lands with less than s caliber of bullet in the case .
Another shoots Verger 107's at .040 off.
These rifles however are true single shot match rifles and will hold a 5 shot group to 1/2 MOA at 1,000 benched and scoped.
For My hunting rifles I set the ammo at least .020 off the lands and sons are as short as .080 off the lands .
Cat

Thanks Cat!! I feel my reloading process is very similar to what’s been discussed. A max load has to be discovered first, and to see the group sizes shape up nicely. Then play with the coal. I too have found in my rifles that 0.10 is a safe place to start as the savage 110 actions seem to like around that measurement. At this time I can only afford savages and they become great shooters if a guys hand loads for them.

[catnthehat]

Originally Posted by DeadEyeGardner

Thanks Cat!! I feel my reloading process is very similar to what’s been discussed. A max load has to be discovered first, and to see the group sizes shape up nicely. Then play with the coal. I too have found in my rifles that 0.10 is a safe place to start as the savage 110 actions seem to like around that measurement. At this time I can only afford savages and they become great shooters if a guys hand loads for them.

I don't work with a max load when doing initial load development but many do .

BTW Don't let anybody tell you a Savage rifle is junk and won't shoot , they have won many big matches and I personally have owned more than a couple that will go 1/2 MOA or better at 1,000!
Cat

[DeadEyeGardner]

Originally Posted by catnthehat

I don't work with a max load when doing initial load development but many do .

BTW Don't let anybody tell you a Savage rifle is junk and won't shoot , they have won many big matches and I personally have owned more than a couple that will go 1/2 MOA or better at 1,000!
Cat

Oh I don’t! I proudly own and shoot them, and I certainly recommend them all the time. They are shooters, and I’ve got some with Over 1000 rounds through them that still shoot great and have had no issues whatsoever.

[DeadEyeGardner]

Back on track and not to derail...

I also was able to get IMR4895 to shoot several different bullets quite well for two separate 308s.

[Dean2]

Originally Posted by DeadEyeGardner

Back on track and not to derail...

I also was able to get IMR4895 to shoot several different bullets quite well for two separate 308s.

I agree, IMR 4895 is my got to powder for the 308. One word of caution, approach the maxc loads in the Hodgdon site with care. For example they show 51 grains with a 130 grain bullet. I hit max velocity of 3150 fps a full 4 grains before that in the last three rifles. I have tried the famous Varget, I don't like compressed loads for hunting. The newer powder I find very good is CFE 223.

[elkhunter11]

Originally Posted by Dean2

I agree, IMR 4895 is my got to powder for the 308. One word of caution, approach the maxc loads in the Hodgdon site with care. For example they show 51 grains with a 130 grain bullet. I hit max velocity of 3150 fps a full 4 grains before that in the last three rifles. I have tried the famous Varget, I don't like compressed loads for hunting. The newer powder I find very good is CFE 223.

CFE is ab excellent powder, and the bonus is, almost no copper fouling.

[DeadEyeGardner]

I just got a new rifle for Father’s Day, chambered in 224 Valkyrie. I read that CFE223 is a great powder for the chambering so I picked up my first lb. so far it seems pretty decent, I’ve got 50 reloads down the tube after an initial 100 break in shots.

I did find that my Lee perfect powder measure doesn’t like the small ball powder like CFE223 as much as it liked dispensing stick powder like IMR4895. Sometimes it seems to leak powder out of the middle mechanism, it also doesn’t give quite as accurate loads every time so the trickler gets worked double time.

I didn’t even think about using it in other loads like 308 or 243, our hunting rifles which are all I load for at the moment