I've been doing searches online and getting a lot of conflicting info. So what does the experts on the THF think?

Do you size new brass?

Some say it puts undo stress on the brass when its not even needed. Others say its a must.

This is for 300 HAM'R new WC brass out of a SBR so not really looking for 1 hole accuracy just minute of pig.

Thanks

Look at and measure your case necks, some brass will be tighter than you want and other brass due to handling and shipping might be dented or the mouth a little out of round. If either of those are the case resize it. If in doubt resize it.

Forgot to add if they are not prepped I at least chamfer the case mouth and that will tell you if it is out of round as well.

I chamfer the case neck and size with a mandrel to ensure case neck is round

Yes.

Neck size.

If you don't the bullets will distort to conform. At the least chamfer the inside necks. Even the fancy stuff shipped in foam gets dinged up necks occasionally.

I am no expert, however, here's what I do, and it has worked for me. 6.5, 308, 270, etc. I size brand new brass. 300 BLK and 357 Mag I take the brand new shiny brass and load it. Zero prep work (I did take some measurements of about 25 or so cases in the bag of 500 to make sure there was decent consistency). When working up a load for my wife's 300BLK I ended up with a .7" group, and a .87" group .4 gr higher. That was my accuracy node. I don't know if it is correct, but it has worked for me.

I have read that you can anneal along with sizing new brass. Seems to help fire forming the new case to the rifle chamber.

I always full size even new brass.

I size all new brass except Nosler Custom. It’s fully prepped and sized when you get it.

First time I go all the way through all new brass. Size and trim. Chamfer and de burr. On rifle brass I also de burr flash holes if they are punched. I may or may not uniform primer pockets. Nosler custom is the only brass I load straight out of the box. Nosler case prep is very good and their brass is very consistent.

If I recall correctly, the Nosler brass that comes in qty 50 boxed is prepped BUT the brass that comes in 100 packages is not.

Kyle, I normally run all new brass with a mandrel, chamfer and deburr.

i must be the exception. not sure how much new hamr brass i've bought, but waaay over 1,000. i've never done anything to it except prime, powder and bullet. chamfered some but not if i was in a hurry. don't believe i've ever had a malfunction with one of these rounds, and i can't tell that i've missed anything with one that i would have killed with more case prep... but who can say for sure?

vid for attn, cuz, well... i'm THAT guy!

K & M neck mandrel through Nosler, Norma, and Lapua.

FL sizer for all others. Almost never do the shoulders get touched. But I want to make dang sure the body of the brass is correct along with the case mouth. The cheaper brass, I will also run through the Giraud trimmer. Deburring the flash holes is also a step for the cheaper brass.

Kyle, I normally run all new brass with a mandrel, chamfer and deburr.

Peterson and Lapua don’t need anything, but any other I will fl resize.

I rarely resize new rifle brass, but I do run it through my RCBS trimmer that chamfers and deburrs.

I don't buy new brass but I would size it before loading if I did.

ya know... you could always shoot some sized vs not sized and see if there's a difference in accuracy

I loaded up around 40 rounds last night. Inspected all the case mouths and they were all fine. Had no problems with seating. Will shoot them Friday and see how they perform. Thanks for all the replies.

If DJones Mr. 300 HAM'R himself does it with exact same components I think it's safe to say it'll be fine.

ha, good one. however, i've blown my face off several times, usually taking advice from others

I don't personally and have never had a problem

Unless the brass is made by Lapua then it will need something done to it. Whether it be resizing, primer pocket uniformity, weighing and separating by case volume, chamfering the neck, or flash hole deburring I will need it.

I do with every piece of new brass, no matter how premium it is. Necks can easily get dinged up during shipping.