RR, The brass is Winchester, I believe his Browning is/has minimum saami specs, and I'll have the rifle around x-mas time to verify that, Jay

Bob, you really trust a bag full of mouth dented brass to always be concentric? It may be but I'd rather not leave it to chance........DJ

AH--the fun of reloading for friends and relatives. BIL not from Medford I hope? Anyhow my guess is it's one or the other. Sometimes bullets need to be seated deeper than factory OAL but usually ballistic tips are streamlined enough that it's usually not a problem. Might be interesting to pull down that bullet that won't chamber and size the case and drop it back into the chamber. I like win brass (I'm assuming its win brass) but I have had some trouble with consistancy lately and I wouldn't let that idea "off the hook". If it is your B>I>L in Medford I would be glad to have him stop by my house with a factory round that does chamber and a couple of the rounds that don't and I'll check them with a bullet comparator and then with my stoney point headspace gauge. It would take me about 5 minutes to get some measurements. D Kraky

No, they aren't necessarily concentric, which is why you fireform. But running them into an FL die where the body doesn't even touch the die, certainly doesn't aid concentricity nor does it alter the brass except for the neck. It does nothing. We weren't talking about necks. Usually an expander takes care of that if it's dented, or a neck die with expander does, but it doesn't touch the body either. A FL die is superfluous at this point. Wait until you fireform to trim and deburr flash holes if you're of mind to. FL die? An exercise in futility on new unfired brass.

I have always done a visual inspection and ran them through the chamber, and than used a neck sizer die with a carbide expander ball,deburred both ends and loaded.

Bob, A full length die on virgin brass occasionally will touch the body of a case. I don't care to have to fireform brass before it will perform properly, why waste the bullets, powder and primer. I like having virgin brass loads shooting 1/4 to 1/3 minute groups at 200-300 yards in some of my hunting rifles. I don't think that I would get the same performance if I didn't prep my brass the way I do. FL die on Virgin brass is an exercise in consistancy.........DJ

Kraky, yes, DALE, using Bob's Abolt 300WSM that he won last year or year before, won two of them actually, loaded 64ish grains of RE22 with 180BTs, very accurate but said one won't chamber all the way, what the hell, new brass, never had any problems before, maybe give him a call about it, Jay

Hey Jay, the WSM's are really picky. If you have a shoulder that's off just a pinch it won't go. I have had some factory ammo that closed tight in my rigs and some that wouldn't even chamber in some of my friends guns. After looking at the ones that wouldn't go with my Stoney point gauge they were invariably 2 or 3 thousandths past the ones that would chamber. These rounds WERE within SAMMI specs, but yet they wouldn't chamber, one manufacturer I spoke to stated that they were making so many rifles in the new short mags, that he speculated that reamer wear was resulting in some chambers ending up on the short side. I have had a few gunsmiths speculate the same thing, but at any rate I'd bet the rounds that won't go are a little long on headspace, and therfore would need enough sizing to bump the shoulder back a bit. I agree with DJ, full length resizing isn't that big a deal, so why not on new brass--it's just another step toward consistency.
Good Luck--D.

I think you are probably OK if you have a real neck sizing die that doesn't squeeze the shoulder. I you use a regular die and just back it off it will squeeze the shoulder and all that brass gotta go somewhere, so the case gets longer. (At least if the case is not a really tapered one.)
I had an "interesting" experience with RP brass in 243 when I first started loading. I just neck sized with a standard die. The load was a very mild load of 4895 behind a 100 grain bullet. The first shot had an awfull "CRACK" when it fired. I needed a piece of 2X4 to hammer the bolt open. Needless to say, I didn't shoot many more of that load. I couldn't figure out what happened. You could almost fit a shotgun primer into the primer pocket and the case looked like a belted magnum, the case head had expanded so much.
I took the components to my guru who had lots of experience and between us we tracked down what had happened. The brass, before sizing, was just a hair longer than max. When I sized it, I had avoided pushing the shoulder back and the squeeze really lengthed the case; enough, in fact, that the seating die actually crimped the case into the bullet.
Lack of experience and bad info nearly ended my shooting career right then. So . . .
I always FL size brass that has never been fired in my rifle, I ALWAYS trim virgin brass and if I want to neck size, I use a real neck-sizing die.

Whatever!

Virgin brass and fireformed brass WILL perform differently. The expansion of the brass absorbs energy and it won't be the same on subsequent loads.

You don't need to waste bullets, etc., to fireform. Virgin brass isn't consistent to start with. Just measure the OAL after fireforming.

We CAN agree to disagree, and we most certainly do!

Fish, You may have something about the 300 WSM's. I used a RCBS Precision Case Micrometer to measure headspace using fired cases from 3 different 300 WSM's. The results were:

HS Precision 2000 .001 to .0015
Kimber 8400 .001 to .0015
Sako Finnlite -.001 to .000

.000 is nominal....

Cases that were only .001 off of nominal spec were difficult to close in the Sako. Bottoming the FL sizing die plus 1/8 turn sized cases to -.003. Hmmmmmmm.......DJ

I've been using super cheap Winchester bullets to form my cases for the first time. They run me about $6.50 per 100 in 55 grain 224, a little more in .308. Are they really accurate? No, but they work really well to give me a lot of practice shooting from my hind legs. If you are a silhouette shooter, you can't practice standing enough.

DJ, I've had similar measurement differentials. I know that I have had some .002 from nominal that wouldn't chamber. At any rate I think the 'shape' of your brass is always important, so in the sake of consistency I always prep all my brass the same, fireformed from factory ammo or virgin.

I'm into uniformity. I ALWAYS full length resize my new brass before loading. Whether I need to or not, I do it. I think this gives your loads the best chance.

Observation: ever since I've full length resized new brass, it has generally taken less time for load developement. But this is only one small step. As the years have gone by, I've also learned new tricks too.

I am talking about fire forming being a step to the finished product, just like trimming to length, etc. I use either cheap bullets or odd lot left overs and some of the half pounds of powder I have left over from projects that didn't work.

FWIW: you folks with the quarter inch shooting hunting rifles need to start going to the bench matches. You won't win but you'll sure be competitive.