Long range load development at 100 yards.

[SG4247]

I am bad about falling in love with groups, and struggle to be able to read targets such as these.

This is a 6.5 x 47 custom single feed AR-10 with a 26" Krieger heavy barrel. First attempt at shooting the Berger 130 VLDT at 100 yards.

The targets show multiple high flyers, and I dont really know where to go next in terms of charge weight seating depth etc..

The 130 berger touches the lands at 2.805" in this barrel. These are all loaded .010" off the lands.

Please help. The photos file name/number is indicates increased powder charge. Berg1, Berg2, etc...

 

[Erik Cortina]

SG4247, I'm having a hard time keeping track of your groups because I have to open and close them to see them. They also are out of order and have different aim points. Another thing that I noticed is that you used .2 gr increments.

Read the instructions on how to do the test and try again. Print the target out and shoot all groups on same page in order and using same point of aim. Load to around 42.0 gr. H4350 but stop if you see pressure signs as you work up load from lightest charge to heaviest.

 

[SG4247]

Sorry, the CTR-1 reticle was difficult to see when on the bull, so I moved over 2" right.

Files are named in correct viewing order Berg1, Berg 2 etc..

 

[SG4247]

How about this?

It is easier to cut and paste in the virtual world!

 

[Erik Cortina]

How about this?

It is easier to cut and paste in the virtual world!

I think I would try 37.8 but would be beneficial to see chronograph numbers.

Also, flyers are part of the group, so they must be included always.

 

[SG4247]

Thanks Erik,

I've shot thousands of rounds of 47L. Just not with H4350. It is very odd to have one of five shots mark very high frequently like this.

Also, some cases are very sooty, like soot all the way down to the rim.

Something is not quite right here..

 

[Hal]

What a great thread, Very Helpful.

+1000 for making this thread a Sticky.............

Hal

 

[warbird2006]

308 Winchester
Savage 29" barrel, 12 twist
168 gr AMAX
Varget
GM210M Primers
-0.020"

 

[Erik Cortina]

308 Winchester
Savage 29" barrel, 12 twist
168 gr AMAX
Varget
GM210M Primers
-0.020"

Do you have any chronograph data?

 

[warbird2006]

Unfortunately I only have magnetospeed and did not want to strap it on my barrel. Shold I get a chrony and do it again?

 

[L1986]

Ok Erik ive used your method to try and tune my22250ai and here are my results looking for your input and if i did this corectly.
Savage action
Mcgowen 22250ai 7 twist
75g amax and RE17
Lapua 1x fireformed brass and Federal LR match primers.
Chrono is a caldwell and not sure on its reliability.
First pick is charge work up. These were seated at 2.135CBTO. Fist and second group are 1g apart, I had a mental moment but the rest are .5 increments. Second group (35g charge) i messed up and shot one shot at next target but imposed it over and this group measued .35''. It looked to me that 35g was the node and chrono numbers supported this. So next i loaded for seating depth test(next pic). Started at 2.128CBTO and up to 2.152CBTO in .003 increments.
2.140 looked really goot to me but i beleave the node is maybe 2.146. After rereading your method i realized i made a mistake because i measued distance to the lands and it is 2.140 CBTO and i should have loaded the initial test at 2.160CBTO. I also wanted to check my chrono numbers because i beleave they are a little slow so i shot a five shot group at 300yds to check actual drop against calculated and it ended up being 3.01'' for five shots.(pic 3). Not great and really want to tighten this up. What are your sugestions here? Sorry for the long post and hopefully this all makes sense.

 

[L1986]

Pic 1

 

[L1986]

Pic 2

 

[L1986]

Pic 3

 

[memo43]

Erik here is my attempt
308 1:10 32" barrel
using IMR 4064
smk 175 seating jam -.020
Winchester brass
wolf mag primers.
If I where to guess I have a node 43.0-43.5
as well as 45.5+

thanks in advance

 

[groundhogassassin]

I recently did a ladder test for my .308 savage axis and went with a powder range to test that guys on here suggested to try. I shot three rounds each from 42.1 to 43.3gr in 0.3gr increments using your method Mr. Cortina. This is what it did. I feel like the big wide groups were results of something I was doing differently every shot, or it could have been a dirty barrel? Do you suggest shooting this again and trying to get better results before determining what charge to go with? I am using Varget powder, 165gr hornady sst bullets, 210m primers. seating depth is 2.260" to the ogive. I know it is touching the lands but I'm not positive as to how much of a jam it is.

 

[memo43]

Went out today to do a seating depth test. Measured to jam -.005 then proceeded to do the seating depth test.
But gatherer measurements of the ogive to be a little more exact.
Erik I want to thank you for passing on the knowledge.
I'm thinking splitting the difference between group 4 & 5.
Load was at 43.3 IMR 4064
I'm going to load some up and head to the range this weekend for a 3x1000
Thanks again
Oh it was a bit windy when I was testing from left to right, but I was determined to complete the test

 

[Erik Cortina]

Went out today to do a seating depth test. Measured to jam -.005 then proceeded to do the seating depth test.
But gatherer measurements of the ogive to be a little more exact.
Erik I want to thank you for passing on the knowledge.
I'm thinking splitting the difference between group 4 & 5.
Load was at 43.3 IMR 4064
I'm going to load some up and head to the range this weekend for a 3x1000
Thanks again
Oh it was a bit windy when I was testing from left to right, but I was determined to complete the test

What is the seating depth at #4 and #5?

 

[memo43]

Erik, the seating depth for 4 is 2.258
5 is 2.255
my measurements at jam are at 2.278 puts me in the ball park of 2.870 for a 175 SMK
I would have get testing more seating depths but the recoil started to increase so I chose to stop.

 

[Erik Cortina]

Erik, the seating depth for 4 is 2.258
5 is 2.255
my measurements at jam are at 2.278 puts me in the ball park of 2.870 for a 175 SMK
I would have get testing more seating depths but the recoil started to increase so I chose to stop.

Load them at 2.258" and it will give you at least .003" room for throat erosion before accuracy is affected.