Help with high and low inpacts at 200 and 300

[Three57]

I am getting the occasional and all too often, high and low impacts.
I would like some opinions on how to fix this and improve my group sizes.
I think a good possibility is that the new brass that I am using doesn't have consistent headspace sizes, which could cause inconsistent pressures and speeds. They all measure under my chamber size. The headspace measurement varies from 1.621 to 1.624. My chamber's headspace is 1.628, so I am not resizing the brass. I could also be way off on what is causing the problem.
Here are my 200 and 300 yard test targets.
Let me know your thoughts

 

[bh-ltr]

Have you had someone else shoot the rifle? Make sure you're not shooting while you're breathing? I'm assuming since you mention you're not resizing that you loaded these. How are you measuring out your powder? What bullets are you using? Not factory seconds right? Are you chamferring and deburring the case necks before seating? Is your barrel free floating? Are you letting it cool a bit when it gets hot? Probably quite a few other things I'm forgetting... But others will bring those up.

 

[Pinecone]

1) Shooter

2) Did you work up the load based on OCW?

OCW Overview - Dan Newberry's OCW Load Development System

 

[mdmorrow]

What rifle are you shooting and how do you have it zeroed?

 

[Three57]

Sorry, I did leave out a lot of information.
I did do the OCW test.
I am using new winchester brass, ramshot tac powder, federal primers, and hornady 178 BTHP bullets.
I have read, understand and have followed the reloading instructions posted in the reloading forum. I haven't resized the brass, because it is all so much smaller than my chamber, I have had to straighten the bullets because the run out on this brass has been really bad. I know the runout will go away once the brass has been fired, but I have a long range course coming up and I don't have time or resources to fire form all of it.
I am reloading on a dillon 550b, the dillon powder charge is throwing the charge and I weigh them afterward with a Gempro 250. According to the gempro the dillon throws just about all of them within about 0.1 grains at very most it is at 0.2 grains and that is rare.
I have been paying very close attention to my breathing, I know that breathing can cause vertical strings. I don't think it is my breathing, it could very well be my follow through and recoil management.
Has anyone else seen headspace differences cause speed variances?
I have only tested speed on 5 of these. Here are those speeds.
2544, 2520, 2534, 2559, 2530

 

[Three57]

It is a Knight SR25 ER, I have it zeroed at 100, I am using applied ballistics to adjust trajectory. It is very close to point of impact with a speed of 2550.

 

[gunfreak101]

I do not know slot but everyone o shoot with only fire forms for bolt guns not semi auto guns

 

[FrozenRopes]

Occasionally I'll see an AR style rifle shoot 2 groups like in your second picture.
It is believed to be caused by magazine feeding from the left and right.
Check to see if single feeding them helps at all. Or keep track of which side of the mag each round is loaded from.
One feed ramp my be slightly different than the other.
Just a thought...