Thread: Getting ES down with 223

Originally Posted by Hunter_Nick

@Pommy I encountered something similar yesterday while I was testing for my 6mm/223 wildcat.

First OCW test was 87gr Hornady boat tails in PSD mil brass, AR2206H and 205M primers. Accuracy was around MOA and ES was up and down between 20-75. I was starting to wonder about the chrony and whether it was giving me duff data. Then I tried another OCW test, but this time was new Lapua cases, 85gr Sierra SP, 2206H and 205m primers. This time, accuracy steady increased from 33mm down to 9mm as pressure increased, and ES steadily decreased from 50 down to 9 with pressure increase.

The two tests were like night and day really, and I put it down to the brass. Like @grandpamac I too wonder if it’s all about the flasholes. I too have hear that Lapua drill theirs rather than punch, could be something in that.

Did you try deburring the flash holes on your PSD brass to see if it would also make an improvement? The military brass is often very low grade which I found out when I got my hands on some WCC brass and saw 10gr of case weight variation was pretty standard - enough to be messing with H2O capacities. That's not what I see with Starline. It's not Lapua-tier consistent, but it's not terrible either.

I have a good bit of PMC brass which I use for 308 now and am getting ES's below 20 after fireforming, annealing, trimming, messing with flash holes.

Current plan is to try 10rd groups with the following...
- Virgin Starline, FL sized.
- Fireformed Starline, annealed, sized, trimmed, fettled flash holes.
- Lapua, same treatment.