Thread: Seating depth adjustment after 600 rnds down barrel 6.5PRC

I found that my 6.5PRC wasn't shooting nice little sub-half moa groups anymore with the load i'd been using.
As i was about to load up a new batch after firing off all of the last batch, with new lots of powder, bullets and the cases are up to their 7th cycle. I thought i'd adjust the seating depth to try get the accuracy back.
143ELDX, RL26 56.6gr, Hornady brass, Fed210m
You can see my old load dev here: https://www.nzhuntingandshooting.co....66/#post976066

Old groups which were indicating it wasn't where it used to be, now at about 0.75moa:
CBTO of 2.264"





So after watching Erik Cortina YouTube clips where he reckons the groups change in windows/nodes of about 0.003" of seating adjustment. I decided to load four 3 round groups increasing at 0.003" adjustments.

I shot starting at the longest COAL. CBTO 2.276" and then 2.272" (yeah i know that's 0.004" diff but that's what the die pushed out also ended up being a 4 shot group because i had a spare empty case).



These groups were good enough for me so initial 'test' was over! Two consecutive 'tight enough' groups indicate to me a better seating depth to use.
I didn't fire the 2.267" or 2.270" as components are bloody scarce.
I know they aren't the compulsory '5 shot' groups, however this is a lightweight hunting rifle and has proven it cant handle anymore than 3-4shot groups.
The load will prove it self over the next few follow up groups and give me a clearer idea of its actual accuracy in time.

What a difference a few 'thou' can make!