Need to fix high ES

[TackDriv3r]

When testing @ 100 using the .308 and 168 SMK / Varget. I used 43.8 grains at 2740 fps average, used a P35 and I am seeing ES of around 25 to 30 fps and I don't like it and knew what will happen at 600 yards. @ 100 yards it shoots .1 to .2 MOA which is nice, but,,,,I won't use it beyond 600 yards.
Tested @ 600 yards, and vertical is about 4.5 inches and an inch wide and I want to fix it, so I went home and tried different primers, BR2 which I'm using, CCI200 and FGM 210 and tested again @ 100 for ES, and same variation of 25-30 fps.
I switched to Hornady 168 BTHP and I'm getting the same 25-30 fps variation.
I'm using .001" neck tension, cases are fired 2 X, annealed until it barely glows under no lights and pull out of the flame, powder is weighed by the kernel, I bumped shoulders .002" using a bushing die, seated .030" off. | I can't think of anything I can do to fix this high ES.

I could guess maybe change the neck tension to .002" or change powder to IMR 4064. Varget is a fine powder for the .308 and I want single digits.
My 6 BR ( Varget ) and 6.5 Creed ( H4350 ) has 3 to 4 ES spread that I'm happy with. But not the .308

What do you guys recommend I do to get my high ES fixed?

 

[Dean2]

First, make sure there is not lube or graphite in the necks as lube will affect things a lot. Then, I would be using a min .003 neck tension. Fast way to tell if neck tension is the issue is to put a LIGHT crimp on 5 rounds and see what you get for ES. Other option it to try seating .005 into the lands. I would try each separately. Final point, what is the SD you are getting with this larger ES. Are you getting occasional outliers and the SD is actually pretty low?

 

[Pdyson]

I think you should give up and sell me that rifle right away. It's obviously a lemon.

Seriously an ES of 35 isn't that bad. I just ran the numbers in my ballistics calculator an SMK at 2740fps avg + or - 18fps (36ES) the drop difference at 800yds is only plus or minus 3" drop. There must be another reason for your 3/4 MOA groups at 600

I don't own a rifle that shoots as good as yours. If I did I wouldn't burn the barrel up chasing better ES numbers. I'd save it for competition and hold my round count low to make it last as long as I could.

 

[308win]

When testing @ 100 using the .308 and 168 SMK / Varget. I used 43.8 grains at 2740 fps average, used a P35 and I am seeing ES of around 25 to 30 fps and I don't like it and knew what will happen at 600 yards. @ 100 yards it shoots .1 to .2 MOA which is nice, but,,,,I won't use it beyond 600 yards.
Tested @ 600 yards, and vertical is about 4.5 inches and an inch wide and I want to fix it, so I went home and tried different primers, BR2 which I'm using, CCI200 and FGM 210 and tested again @ 100 for ES, and same variation of 25-30 fps.
I switched to Hornady 168 BTHP and I'm getting the same 25-30 fps variation.
I'm using .001" neck tension, cases are fired 2 X, annealed until it barely glows under no lights and pull out of the flame, powder is weighed by the kernel, I bumped shoulders .002" using a bushing die, seated .030" off. | I can't think of anything I can do to fix this high ES.

I could guess maybe change the neck tension to .002" or change powder to IMR 4064. Varget is a fine powder for the .308 and I want single digits.
My 6 BR ( Varget ) and 6.5 Creed ( H4350 ) has 3 to 4 ES spread that I'm happy with. But not the .308

What do you guys recommend I do to get my high ES fixed?

If your goal with the rifle is to shoot 600+, then I would do my testing at 600+. 100yrd groups make you feel better, but really are meaningless. I'd say if you are getting 4.5" vertical at 600, your load is wrong. Forget about the ES/SD numbers and let your target tell you what the rifle likes? Go back and try a ladder test at 600 and find what powder charge you need? If you know how to read your results from the ladder, you should find a forgiving load that gets your vertical under 3" or less.

As an example, I was running a ladder on my .223 (.3gr increments) at 634yrds and found a series of powder charges that ranged 1.2grs for an ES of 110fps across 4 different loads. 110FPS is crazy high ES! The vertical was 1.5 inches or .22MOA. This was 2 shots per charge (8 shots), so I was very confident in the results and loaded up the remaining right in the middle of the 1.2gr range. I can't quote you what my ES is on that load, but it hits right where it's supposed to every time I go shoot it.

Sorry this got long winded, but short of the story is.....don't get hung up on ES/SD until you start getting out to that 1000yrd + range. Good luck

 

[TackDriv3r]

First, make sure there is not lube or graphite in the necks as lube will affect things a lot. Then, I would be using a min .003 neck tension. Fast way to tell if neck tension is the issue is to put a LIGHT crimp on 5 rounds and see what you get for ES. Other option it to try seating .005 into the lands. I would try each separately. Final point, what is the SD you are getting with this larger ES. Are you getting occasional outliers and the SD is actually pretty low?

I cleaned my necks with a nylon brush.
As for SD, I turned my printer off and never bothered to check for SD, just the ES. What does the SD tell me if its good or not? What do I look for?
I switched from a .336 bushing to a .335 which will give me .002", its all i have for now. Just need to test it.

 

[Jud96]

I personally wouldn't worry about 25-30fps ES being high. That's really not that bad. I'd test different seating depths and loads at 600 if you want to shrink your vertical.

If you're concerned about the high ES though, I'd try different powder charges going up from your load now in 0.3gr increments and down in 0.3gr increments for a few loads each way, as long as you don't hit pressure. I'd also run .003+ neck tension. That seems to help things more than lighter neck tensions. Finally, if trying more neck tension and different loads doesn't help, I'd switch powders. How clean is the barrel when doing these test?

 

[Dean2]

High ES with low SD says you have one or two outliers. High ES and high SD says you have a lot of variation between loads. If you have only a few outliers then the fix is usually different than high SD. A low SD or ES does not guarantee small groups.

Standard deviation is a measure of the amount of variation or dispersion of a set of values.[1] A low standard deviation indicates that the values tend to be close to the mean (also called the expected value) of the set, while a high standard deviation indicates that the values are spread out over a wider range.

 

[TackDriv3r]

I personally wouldn't worry about 25-30fps ES being high. That's really not that bad. I'd test different seating depths and loads at 600 if you want to shrink your vertical.

If you're concerned about the high ES though, I'd try different powder charges going up from your load now in 0.3gr increments and down in 0.3gr increments for a few loads each way, as long as you don't hit pressure. I'd also run .003+ neck tension. That seems to help things more than lighter neck tensions. Finally, if trying more neck tension and different loads doesn't help, I'd switch powders. How clean is the barrel when doing these test?

Barrel is pretty clean, shot about 20 rounds before the tests.

 

[Mike Matteson]

Change your brass. Unless you are using top end brass to start with.
All I see is you are annealing, That helps! You haven't said about any other steps. Cleaning flash holes, Primer pockets dept, seating primer? Metering your powder. Case lengths. that enough for now.
What you are doing presently is good for at least 500yds.

 

[TackDriv3r]

Change your brass. Unless you are using top end brass to start with.
All I see is you are annealing, That helps! You haven't said about any other steps. Cleaning flash holes, Primer pockets dept, seating primer? Metering your powder. Case lengths. that enough for now.
What you are doing presently is good for at least 500yds.

I did all case prepping and using Lapua brass.

 

[Mike Matteson]

You have great brass. How do you seat your primers? There has been a lot on seating primer here as of late. Case lengths are all the same and not varying by several thousands. I got in 500 case here the other month. They varied several thousand in length. How are you setting your powders charge weight?

 

[Rick Richard]

Some may "shuck" this practice, but for whatever reason it works for me. Weight sort the brass in various batches attempting to get a batch as close in weight to that bunch.…..Waiting for the criticism.

 

[Mike Matteson]

Some may "shuck" this practice, but for whatever reason it works for me. Weight sort the brass in various batches attempting to get a batch as close in weight to that bunch.…..Waiting for the criticism.

That's what I did a long time ago. Also did it a couple of years ago.
I have changed my ways. I use volume weight now. Not brass weight. It's not the weight of the brass, but the volume inside, and what it will hold.
I got my ways changed here, and darn thing I had to agree.

 

[TackDriv3r]

You have great brass. How do you seat your primers? There has been a lot on seating primer here as of late. Case lengths are all the same and not varying by several thousands. I got in 500 case here the other month. They varied several thousand in length. How are you setting your powders charge weight?

I just seat my primers by feel using a RCBS hand priming tool. Case length is mostly .001" in variation, a few as much as .002" . Powders are weighed by .02" grain, actually to the kernel using the FX120i.