Purchased New brass what to do first?

[mookiie]

Hey guys I just started to reload in the last 4 months but it had always been from fired factory ammo. I am getting a 7.7 x 58 mm Jap arisaka type 99. I bought some unfired, unprimmed brass.
My question is what should I do next? Is there a need for trimming them? Do i need to run them through the sizing die?

any info would be appreciated.

 

[MEHavey]

(my) Standard procedure is to treat them like once-fired: Uniform the primer pockets, FL resize, then check length/trim if/as required.

 

[Steve H]

In addition to what is said above I would deburr the flash holes.

 

[noylj]

This isn't a benchrest rifle, so why play with the primer pockets or flash holes?
Simple resize, to iron out any dings from shipping/handling, check length and trim as required.
Unless your rifle and you can shoot less than 0.5" at 100 yards, leave the primer pocket and flash holes alone unless you simply have to do it to feel good.
After a couple of firings, you will need to check the case neck thickness and ream out or outside turn to make neck concentric (again, if this makes you feel better).

 

[Walkalong]

Yep... Size em, trim em, chamfer/deburr em, tumble em, load em. If they don't need trimming, skip the deburr/chamfer & tumble.

 

[Offfhand]

Excuse me, but let's go back to the beginning, with logical questions in order: You bought some new brass. Fine, What brand of brass?

 

[mookiie]

PRVI BRASS 7.7x58 JAP UNPRIMED

 

[qajaq59]

Size, trim to square the mouth off, and make sure there is a flash hole.

 

[Offfhand]

Mr. Mookiie, There was a reason I asked which brand of brass you bought, which I should have explained: A long time source of 7.7 brass has been Norma, which is excellent,stuff and comes boxed. The only prep it needs is a slight mouth chamfering and it's ready to load. Other brands are sometimes bulk packed and may have some slight damage, with some flattening of the neck being common. Which of course causes problems with bullet seating, so they need to be rounded before loading. This is best corrected by running the necks over a dedicated mandrel. For the small amounts of 7.7 you'll probably be loading the expense of such a mandrel isn't justified but you can accomplish the same thing nearly as well by passing case necks over the expander button in sizing die. After that simply chamfer the mouth slightly and you're good to go. Be cautious about other case "preps" such as messing with primer pockets, etc. Your 7.7 isn't going to be a bench rest rifle anyway.