New brass 6.5CM brass, FL and trim?

[BravoSierra]

I've got about everything I need to start reloading. But everything I see instruction wise is related to FL sizing on already fired brass. Mine is new hornady. Any tips, tricks, or dont's I need to be aware of for new brass?

rifle: Bergara BMP 6.5CM never fired/new
brass: hornady new
primer: cci br's
bullet: 140 RDF
powder: H4350

reloading: Lee decapper, Redding type s with expander removed, sinclair mandrel die, forster micrometer bullet seater. Still looking at what bushing ill need for sizing.

 

[shoot4fun]

My tip would be, unless you are expertly neck-turning your brass, to put the expander ball back in the die.
You always want the most round neck to the inside, if you can visualize what I am saying, and the expander ball makes that happen. If you don't like the "drag" from the ball then get some Redding Dry Media Neck Lube and dip the case neck in before using the die. It will be nice and smooth then and may even help controlling those unexplainable fliers.
Use the expander mandrel for first loading to make sure you don't have too much neck tension. I think you'll likely want to get a 288 and a 289 bushing to experiment with just how much tension your gun likes. Less is sometimes better than more unless you are shooting a gas gun.

 

[BravoSierra]

Thanks! Ive no experience with neck turning. I was going by what the 65 guys were showing using the mandrel meant for interior neck sizing not the one for neck turning. The belief was that its more uniform and works the brass less, less run out, etc. At least thats my understanding of what they were saying. Anyhow, i can put the expander back in no prob.

Ive always trimmed on new brass for pistols, but not sure if trimming new brass is a must for precision loading, really intended for once fired?

Roger that on the bushings.

 

[spife7980]

You are correct in your understanding. If you're going to mandrel each time leave the ball out and don't worry about it. The mandrel will do the same thing as the ball but better. I agree on just mandreling the first loading provided the factory brass will chamber.

If the brass necks are long and over spec trim it back down. Some come long so that you can trim to your spec rather than being too short. I would trim them all to be uniform myself.

When you load your first rounds measure the neck diameter of the brass with the bullet seated. Select a bushing that is .002 smaller than that. You could also go .003 or 4 smaller just to ensure that your mandrel will work the brass rather than just passing through should spring back and thickness variations create a situation where that's possible. You're working the brass a bit more but it's not going to be a drastic difference in case life.

 

[BravoSierra]

Roger that. I have 300 pieces from the same lot. Just tested 5 pieces in my gun. They all chamber, a bit tight, smooth, but still chamber nicely. I will check all of them before doing anything else. Will check the length and trim for uniformity. Will mandrel them before seating. Will check one after seating and subtract to get propper bushing size.

think i got my next steps. Appreciate it all!

 

[padom]

Just shoot them or if you really want mandrel them but not necessary. Then bump the fireformed brass back .0015-.002, mandrel the necks then start load development.

 

[BravoSierra]

For posterity, the CBTO with the 140 RDF to the lands with the BMP is at 2.242" for my rifle. The dummy rounds i just made to setup the seater, after the mandrel, came out at 292. 290 bushing and a 289 should get it.

Some of the new brass is a bit hard to close. Just a bit too much resistance on the bolt when closing.