New Brass w/ Bushing Die. What is your neck sizing procedure?

[ICanSeeYourPixels]

I am reloading 6mm creedmoor Alpha brass using a Redding Type-S FL Bushing Die. With my once fired brass, I am loading to -0.002" neck tension with the bullet using a 0.270 carbide bushing.

For virgin Alpha brass however, the starting neck outer diameter is 0.268. My previous round of load development, I elected just to send it with -0.0035 of neck tension and did not full length or neck size. I ended up having pressure signs in that 10rd batch of ammo. Absolutely was a little too aggressive on the charge, but also see neck tensions as a potential factor as well.

So I guess my questions are:

1. Are you doing any processing of virgin brass before priming and charging?
2. If so, Mandrel only? Full length size then mandrel?

I am utilizing these reloads for PRS, and much like the AutoTrickler vs. Chargemaster debate, I do not think my use case will be impacted at this point by not neck turning. I've accepted the variation you will see in neck tension by controlling it with the OD of the case neck, but am curious if I am introducing a little too much variation by having significantly more neck tension on the 1st reload vs. the 2nd.

Thanks!

 

[coast range]

Following…

 

[Molon Labe]

Chamfer and deburr. Then run a mandrel. No need to size. That’s moving brass when you don’t need to.
Your neck tension is not causing pressure. It’s the charge weight.

 

[wind gypsy]

Chamfer/debur if needed, expand with mandrel, tumble in used/dirty media, shoot.

 

[Dmoua]

Tumble, trim, chamfer/debur, and run the brass through a mandrel.

 

[sierracharlie338]

Chamfer and deburr. Then run a mandrel. No need to size. That’s moving brass when you don’t need to.
Your neck tension is not causing pressure. It’s the charge weight.

Bingo

 

[ICanSeeYourPixels]

Sounds like "new brass must be expanded" is the universal answer. Thank you everyone.