Found OCW, how to work on SD and ES?

[psmith]

Okay so I did a ladder test and a OCW test and both showed similar results. Picked the charge and played with seating depth and now have decent groups. Now how do I go about reducing standard deviation and spread? I will be getting a CED M2 as soon as Sinclair delivers it so I want to know if I'm on the right track. Would I have been better to look at this before picking a powder charge or will the loads at the right powder charge natually have good SD numbers?

I don't have any data to comment on so this is a bit premature but I want to think about the next steps to achieve better consistency. Caliber is 308, lapua brass, 175 smk, BR2's Varget. Steps I do now are case trimming each time, full length resize and powder measure but I don't sort bullets, weigh cases, trim meplats, or turn necks.

 

[glock24]

Re: Found OCW, how to work on SD and ES?

I've read changing primer brands can sometimes improve velocity variation.

 

[DocB]

Re: Found OCW, how to work on SD and ES?

psmith,

With SMKs, sort by OGL and trim meplats. Clean cases with a chemical cleaner and clean necks with 4-0 steel wool on a brush. Seat primers by hand, and uniform primer pockets.

What you choose to do is up to you, these are the easiest to do unless you wish to get in neck turning, etc. BR2's and Varget are a very dirty combination, so you really need to clean cases.

HTH,
DocB

 

[BCP]

Re: Found OCW, how to work on SD and ES?

What are your numbers like now? And are you getting vertical stringing etc or just worried about SD ES because...

 

[Suasponte]

Re: Found OCW, how to work on SD and ES?

Annealing cases, a high quality scale for very accurate charge weights (Denver Instruments MXX-123, Acculab Vic-123, If you got the $$$$$$$$$$ Prometheus).
I have been using a Lyman M5 scale tuned by Scott Parker along with Target Master Powder trickler Thanks to Allen in the Uk.

Consistant Neck tensions and charge weights are the road to good ES's and SD's.

I find a load that groups and work it down from there.

Terry

My Scale setup that I use! The Second charge was high dur to me bumping the pippet on the trickler and knocking a few extra grains of powder out. I have been using this setup for close to a year now and loads are all running below 40fps ES.

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