New 6.8 SPC Brass Case Length Question

[sawacs]

I am trying to take a few more steps during new brass processing to squeeze as much accuracy out of the loads as I can with an ARP 16" barrel.

The new SSA 6.8 brass measures anywhere from 1.669" to 1.684" in length. All of the brass will chamber just fine with room to spare but the length is all over the place.

Do you guys worry about trimming the brass before or after the first firing? If I were to trim before the first firing, should I trim all of the cases to the smallest length which was 1.669"? Somewhere around half of the brass measured between 1.674" and 1.677" so I grouped those together.

Lastly, what do you guys use to smooth the case mouth out after chamfering inside and outside? Steel wool?

Thanks!

 

[thatguyshm]

Are you crimping or not? I am still using old stock SSA brass, when it's new I shoot then trim it all even. I don't crimp any 6.8 any longer, never found it to help and still have low ES. If you crimp you'll get best consistency with brass all trimmed the same, just remember if you don't trim to the same length every time, you may want to reset your crimp as your cases grow

 

[sawacs]

With the 6.8 stuff, I am simply running a KM expand mandrel down through the necks on the new brass, .003 neck tension, then seating the bullet followed by a light crimp with the factory crimp die. After the first firing, I will size, trim, and seat without using the factory crimp die. However, if I am loading up some hunting rounds, I always finish with a factory crimp.

Thanks!