Prep work required on new bulk unprimed brass such as the Winchester 100rd bags or the Hornady 50rd boxes?

 

Everything that applies to any other brass if you want to do it but it's not required.  Many do run them through a sizer to square up the neck for better consistency.

I usually uniform the primer pocket and de-burr the flash hole.

Well, look at it this way,  your bulk brass has traveled a long way banging and bouncing around it's it little cardboard box.  Think maybe some of those case mouths may have gotten dented or out of round?  Chamfering the inside of the neck is a good idea after trimming to length,  it's also a good idea to chamfer new brass, same reason, burrs and sharp edges that the factory isn't going to clean up for bulk brass sales.

I treat them just like once-fired range pick ups.  Then I know all is well.

I full length size,trim, deburr flash holes, uniform primer pockets, chamfer case mouths and turn the necks of all my new cases.

Well even some of the Lapua isn't ready to go anymore.  They seem to have more burred flash holes now.

All the other brass for precision work always got the treatment;

-FL resize
-trim to length
-flash hole deburr
-uniform primer pockets

and sometimes a neck clean up with a outside neck turner.

There are other things I should do but don't is seperate cases by weight, seperate bullets by weight and ogive location even.

Nosler Custom Brass comes RTG.
Weight sorted
Chamfered Case Mouth
Deburred Flash Hole
Sized
Ready to load
I got 2 50 ct. boxes Recently for my B-Day from my brother, this stuff is almost too pretty to use.
In return, just because, he gets 200 once fired LC with all that done to it by me, primed too.

I've got 300 pieces of Lapua made .223 brass that is the most consistent brass I've ever seen, out of 100 random pieces 75% weighed exactly the same and the other 25% was only +/- .1gr max different in weight, not to mention every piece measured the same ogive(shoulder) length using my Sinclair bump gauge/caliper to check and every piece was trimmed to 1.749" with no variation at all with a smooth inside and outside chamfered neck(almost like it was rounded some how).

Any way it just sits in a box looking pretty because I dont think I can shoot good enough to take advantage of it when I'm getting .4" 5 shot groups now with match(no neck turn) prepped LC & Hornady brass.

I have 500 pieces of the new Hornady brass your talking about and it needs to be just ran through the sizing die at the least, the head space on some of mine was to long to even fit the case gauge new.

I would FL size, uniform PP, uniform/deburr flash hole, trim if needed(not likely), and chamfer and deburr the case mouth before loading like I do all my brass if it where me.JMHO

Exactly what I do as well.

Somebody said it like this in the past:

Just because new brass has never been loaded does not mean it is ready to load.

jonblack

I always resize brand new brass, regardless.  

If it's rifle brass, I'll measure it too, just to be sure, and trim if necessary.  

Never bought and used brand new rifle brass though.

Well if you buy it new and pay the high price it ought to be ready to go like it is made.Remington used to sell it new in twenty and fifty round boxes just the brass.What do the companies do when they load new ammo to sell commercially? Do they size,chamfer and deburr the new brass they use? I would guess not and it irons out when you buy and shoot it

Update:
Loaded 50 Nosler Custom brass .223 today
I random sampled and checked in Dillon case gauge,all perfect, but short
Primers were very tight going in but seated below flush
Fired today, all fired and cycled fine

They don't trough it into a bag and ship it across the country either.

This.

The one time I bought new Remington brass (500 pieces in bags), it all loaded up fine without any brass prep. Note, however, that I was crimping all the rounds as well, so neck tension wasn't an issue.



I'm unlikely to ever buy new brass again... but if I did, I'd probably size it and run it through the Giraud trimmer. I just don't see the point of paying a quarter for a piece of brass that I can get once-fired for 7 or 8 cents. That first shot with new brass costs you an extra 18 cents...



If I was trying to make ultra-accurate stuff, it might be worth it. I do have 100 pieces of new .223 Lapua brass that I bought on a whim... it's still sitting in the box...