Analyze these targets with me

[loudandproud]

Second half of my OCW development:

Low wind, 2-4 mph max.Shot at 300 yards

Savage 10FCP
Criterion 20" Bull - 308 Winchester
NSS Barrel Nut and Recoil lug
Modded B&C Medalist Stock
Devcon bedded
Rifle Basix Sav2 trigger

180 Grain Sierra Gameking
Lapua Brass
CCI 200 Primers
Varget: 43.5 grains

Adjusted from .005" Jam into lands all the way to .050" off the lands.

These seem to show the most promise.
Target #1: Cool barrel, Low vertical
Target #3: Warm Barrel, Lowest vertical out of them all, but a lot of horizontal.
Target #6 is the smallest group and it was shot when the barrel was moderately warm...

Which do you think shows the most promise... Im not to good at judging these things.

 

[pell1203]

Not sure what you are asking for help on. Post shows 3 separate targets with similar group sizes shot at varying barrel temperatures. When first reading your post I expected you would be trying to determine how varying the bullet jump would affect accuracy at the specific loading of 43.5 gr Varget but I see no indications as to what jump was used for each shot.

Given the info provided, all that can be said is there are 3 different groups with relatively consistent groupings in the first two targets, followed by perhaps a POI shift as the barrel got hotter.

Hard to help unless more specific information is provided. At least that is all I can see... others may have more insight.

 

[loudandproud]

Not sure what you are asking for help on. Post shows 3 separate targets with similar group sizes shot at varying barrel temperatures. When first reading your post I expected you would be trying to determine how varying the bullet jump would affect accuracy at the specific loading of 43.5 gr Varget but I see no indications as to what jump was used for each shot.

Given the info provided, all that can be said is there are 3 different groups with relatively consistent groupings in the first two targets, followed by perhaps a POI shift as the barrel got hotter.

Hard to help unless more specific information is provided. At least that is all I can see... others may have more insight.

1st group is .005" jam, "3rd" is .005" off and "6th" is .020" off.

The first two groups had .8mils of elevation...the last had .7. Overshot my correction.

My question is which would you choose and why? Go for tightest group or least vertical spread

 

[pell1203]

Typically, one would go with the most rounded group, but realistically your groups are close enough to be statistically insignificant given the similarity in group sizes you got. I'd probably go with the .020" jump, perhaps a bit less, but the targets say bullet jump is tolerated fairly well and is not going to be a big player given what you've shown. Not sure what your other targets may indicate trend wise.

However, I'm still somewhat confused on the math/notations shown on the targets. What is the division by 3.123 about? Were these target shot at 300 yards?

If targets were shot at 100 yards then the MOA numbers you have of 1.58 MOA for #1, 2.18 MOA for #3, and 1.356 MOA for #6 look about right.

1 MOA @ 100 yards is approximately equal to 1.047" @ 100 yards.

 

[loudandproud]

Typically, one would go with the most rounded group, but realistically your groups are close enough to be statistically insignificant given the similarity in group sizes you got. I'd probably go with the .020" jump, perhaps a bit less, but the targets say bullet jump is tolerated fairly well and is not going to be a big player given what you've shown. Not sure what your other targets may indicate trend wise.

However, I'm still somewhat confused on the math/notations shown on the targets. What is the division by 3.123 about? Were these target shot at 300 yards?

If targets were shot at 100 yards then the MOA numbers you have of 1.58 MOA for #1, 2.18 MOA for #3, and 1.356 MOA for #6 look about right.

1 MOA @ 100 yards is approximately equal to 1.047" @ 100 yards.

These are shot at 300 yards. I was use 1.041in/hy but I stand corrected.

 

[sib1948]

They look pretty much the same to me also. Other than my first cold bore shot, I have found much shift. I use IMR 4064 at 43.9 gr. with Berger 185 gr. VLDs, so you seem to be close. Found very little difference on varying the seating depths on my rifles. I think sometimes we tend to over think things. I'm a Tactcal (not Benchrest) shooter!

 

[loudandproud]

They look pretty much the same to me also. Other than my first cold bore shot, I have found much shift. I use IMR 4064 at 43.9 gr. with Berger 185 gr. VLDs, so you seem to be close. Found very little difference on varying the seating depths on my rifles. I think sometimes we tend to over think things. I'm a Tactcal (not Benchrest) shooter!

I think my thinkin has been tainted by those benchrest guys lol.

 

[glockaholic]

I've heard that you either should be into the lands or out, not close. A piece of paper is .003 and being 1 or 2 thou off on individual cartridges will have more influence when close to lands. So either .010 in or .010 out is more consistent. Your gun seems to like .020 out so go with that. Less pressure than being in the lands.

 

[dauntedfuture]

I would be happy with any of them unless you are shooting BR. They are all good groups and the difference in group size is statistically insignificant with the 3 single 5 shot groups. Since they are all so good, and if it was me, I would look at the velocity numbers for each group fired. If the ES is low on each group I would pick the "not jammed" load. If one load ES (and a lesser extent SD) is lower then the others, I would shoot it in a match if I were shooting NRA HP, LR or F Class and see what happens. If its a multi shot match, you could shoot one relay with each load and get a good comparison. Your MOA is easily good enough to clean the targets... The velocity spread is another issue all together that will induce vertical dispersion at range that you will not see at 300. Just for reference the standard for an "international rifle" is 1.5" 10 shot group at 300M from a machine rest and you are there/almost there. The last group could also be a little low from changing light conditions, wind or mirage.

 

[loudandproud]

Update.

I went with the load .020" off the land.

Chrono'd 15 shots today.

AVG: 2544
ES: 9
SD: 4.2

Here is the first group at 100 yards. 5 shots, cold bore. Props to Criterion and sierra...damn accurate hunting bullet.

 

[pell1203]

Nice shooting! Looks like you got it figured out for sure!