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Where is my accuracy?

You are perfectly right. I plan to let a competent gumsmith to double check my gun, thank you for your recommendation. I use CCI BR4, Berger bullets and VV powder. On this particular load I disclosed pretty much everything on the reloading process since I was using virgin brass.
I emphasized process because small changes can have significant impact on the target.
Assuming you used a systematic way to get to your powder charge and seating depth, if you show how yo got there then you can get meaningful input regarding what to do next.
Show how you are developing your load. Here is link with the method I use. It provides information regarding what I am doing and the results I am getting that can be followed and criticized. Whatever process you choose, change one thing at a time.
 
I prepared my first batch of ammo using KM arbor press+ LE Wilson die. Fresh Lapua brass, trimmed to length, case neck expanded using carbide mandrel. BR4 primers. I checked the headspace and CBTO- I had 1thau variation in my first batch of ammo. Seating force displayed by KM mhc dial indicator was between 75-80.

I expected superb accuracy from this ammo. Unfortunately, this ammo produced normal accuracy at 100m. I was using a standard benchrest target. I expected to hit X exclusively. In 10 shots I had only 3 Xs. Most of the shots were placed on the edge (see attached). I assume also shooter's error since I was playing a little with my rear bag and my position behind the gun was not the same throughout my session.
...and in those ten shots what's your ES and SD? Who cares about the hole in the paper? That's not important.
I prepared my first batch of ammo using KM arbor press+ LE Wilson die. Fresh Lapua brass, trimmed to length, case neck expanded using carbide mandrel. BR4 primers. I checked the headspace and CBTO- I had 1thau variation in my first batch of ammo. Seating force displayed by KM mhc dial indicator was between 75-80.

I expected superb accuracy from this ammo. Unfortunately, this ammo produced normal accuracy at 100m. I was using a standard benchrest target. I expected to hit X exclusively. In 10 shots I had only 3 Xs. Most of the shots were placed on the edge (see attached). I assume also shooter's error since I was playing a little with my rear bag and my position behind the gun was not the same throughout my session.
Don't worry about the group...worry about ES and SD. If you do your part with single digit ES and SD numbers...that 12 gauge size hole will be cut in half at 100m even after ten rounds.
 
...and in those ten shots what's your ES and SD? Who cares about the hole in the paper? That's not important.

Don't worry about the group...worry about ES and SD. If you do your part with single digit ES and SD numbers...that 12 gauge size hole will be cut in half at 100m even after ten rounds.

Oh, my!!!
 
All I'm saying is if you have low ES and SD in theory they're all shooting the same. We're talking 100m here and he's not shooting his Grandpa's deer rifle. Shooting 100m groups should be pretty boring. Am I wrong?
 
All I'm saying is if you have low ES and SD in theory they're all shooting the same. We're talking 100m here and he's not shooting his Grandpa's deer rifle. Shooting 100m groups should be pretty boring. Am I wrong?
What?

What discipline do you compete in?
 
I built a rifle a few years ago that I had a group size goal of half inch or better groups at 100 yards.5 groups of 5 shots with the average spread being less than half an inch at 100 yards.After barrel break in and some load development,it shot a .458.I was satisfied,but I wasn't about to give up on making it better.I modified,fitted,bedded and installed a new stock a year or two later.The stock design helped noticeably.It has a flat 3 inch wide forend that is parallel with the bore,which helped the rifle to lay down in the front rest.Then came a Tubb aluminum firing pin/dual spring setup.Improvement?Not that I could easily see.And then came a 2 ounce trigger.Definite improvement.Quarter inch groups became more frequent.I tinkered with the load some more.Got a new L.E. Wilson seating die.Helped a little bit more.Started seeing I wasn't staying the scope and my follow through was terrible.Shot lots of rimfire and did a lot of dry firing.More consistent for sure.Got a little better front rest(Caldwell Rock BR).Made things a little better.Heard the words of an old benchrest shooter who said"If you don't have a premium rock solid front rest and you're trying for quarter inch groups,you're just wasting good ammunition".A shooting partner let me use his Seb neo rest for a while because he had some health problems.Ta-Daaaa.With my best loads it will go below a quarter of an inch very regularly.One group was .184 and the other one was .103,five shots at 100 yards.Maybe what I've just said will help to illustrate how many factors are involved in getting a rifle dialed in and screaming.It's a long way to get a rifle to shoot under an inch.It's much harder to get that rifle to shoot half an inch.Going for a quarter inch is even more difficult.Sweat the details,the little things add up and it takes many times the work to shoot.
a quarter inch group.
And yes,maybe in theory ES/SD will allow a rifle to shoot a perfect group,but I've seen pretty wide numbers in both out shoot loads that have bigger numbers.
 
All I'm saying is if you have low ES and SD in theory they're all shooting the same. We're talking 100m here and he's not shooting his Grandpa's deer rifle. Shooting 100m groups should be pretty boring. Am I wrong?

What no one here is willing to say is that idea on ES/SD isn't remotely correct. What matters is group size on paper. It's very common to see the smallest group not have the smallest ES/SD. When a load is well tuned it will shoot to the same place with a 20-30 fps velocity variation.

ES/SD does tell us the quality of our loading practices, and if the ES is very high it tells us something is wrong with the load. Other than that, ES/SD is meaningless.

When we tune at 1000 yds for BR, we often don't even use a chronograph.
 
What no one here is willing to say is that idea on ES/SD isn't remotely correct. What matters is group size on paper. It's very common to see the smallest group not have the smallest ES/SD. When a load is well tuned it will shoot to the same place with a 20-30 fps velocity variation.

ES/SD does tell us the quality of our loading practices, and if the ES is very high it tells us something is wrong with the load. Other than that, ES/SD is meaningless.

When we tune at 1000 yds for BR, we often don't even use a chronograph.
After thinking about it that makes better sense to me..ES and SD as just an indicator of how consist our rounds are after loading. When I shoot groups it's at 200 yards because that's as far as I can go. MOST of my better groups are from the lower ES/SD numbers. Plus where I shoot it doesn’t not get much wind at all. I just thought the numbers were the hard data we're supposed to be going after.
 
After thinking about it that makes better sense to me..ES and SD as just an indicator of how consist our rounds are after loading. When I shoot groups it's at 200 yards because that's as far as I can go. MOST of my better groups are from the lower ES/SD numbers. Plus where I shoot it doesn’t not get much wind at all. I just thought the numbers were the hard data we're supposed to be going after.

That's what I have found too. While I do my fine tuning at 1000 yds w/o a chrono, when I do chrono those loads the ES are usually in the low teens or high single digits.
 
You stated you are using VV powder. Did you perchance start using a new lot of Powder?

Newer lots of certain VV powders are showing a much faster burn rate than older lots. My load i use with N140 showed an 80fps increase with my 6BR with a new lot and I had to drop the load 1.5grs to get the accuracy back.
 

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