hy, i'm just starting into reloading, and what i have read, the most accurate reloaded ammo. is when you just neck size, not the full case resize. These reload's for my 300 ultra will only be used in my gun. Just looking for advice to set me straight on this subject, any info would be appreciated. Thank's:Rick.

I'm not sure this will set you straight, but I only neck-size all my bottle-neck cases, and then only the first 1/2 of the neck.

Works for me...

I neck size for my rifles as a rule BUT I always full length resize ammo I am going hunting big game with. Also, after several reloadings the brass will become hard to chamber, then you need to full length resize and start over.

Most of my shooting now is from the bench, and I pretty much neck size everything. I find that
sizing about a third of the neck is sufficient to hold most bullets. I think Beemanbeme makes a good point though about full length sizing hunting loads. You've got much more riding on your shots in the field than when punching paper. Best wishes.

Cal - Montreal

Yep. Neck sizing only for one bolt action rifle is just fine. What you'll have is brass that fits your rifle's chamber exactly. Neck sizing brings only the neck back to spec. So the bullet will go in when you place it in the case mouth and stay in when you seat it. Crimping is usually not required and is detrimental to really good accuracy.

I neck size only also,but after 3 fireings I full lenth resize to make sure they chamber,and you dont have to buy a neck sizeing die either,if you soot the caseing with a candle,then back your die out about the thickness of a dime, now put the caseing in the press and lower the ram,you will see how far the die is sizeing by the soot being removed on it,then adjust the die so that is is just about to touch the shoulder,you will have to soot the caseing several times before you get it right.hope this helps and good luck.

Hey Richard, I'll disagree with most of the above and say that Partial-Full Length Resizing(P-FLR) is more accurate than Neck Sizing.

I've run a number of Blind Tests over the years to re-verify this issue to my satisfaction. Actually, it is simple to understand why P-FLR is "potentially" more accurate. A P-FLRed case is held in tension between the Bolt face and Chamber shoulder. This causes the CenterLine of the Case and the Centerline of the Chamber to be closer to perfect alignment. Basically a -0.002" Headspace, or crush fit.

When Neck Sizing, the case sets at a "slightly skewed angle" in the chamber since it falls a small amount to what ever is the low side of the Chamber. Basically a +0.002" Headspace, or loose. This amount of Headspace "varies" from shot-to-shot until you need to "bump the shoulder back" as the Neck Sizing folks call it. Thus once again creating excess Headspace.

No doubt Neck Sizing is faster since you normally don't need to lube the case and then remove the lube. So, if quick reloading is important to you, then Neck Sizing does offer an advantage.

To P-FLR, start with your Full Length Die about a Dime's thickness above the Shell Holder. Then lube a fired case, squash it, wipe the lube off and try it in your chamber. If the Bolt closes with just a bit of resistance, lock the Jam Nut in place.

If it does not close with a bit of resistance, screw the Full Length Die in 1/8th turn and repeat until you feel the resistance.

If you go too far, it will begin to feel loose again and now you are just Full Length Resizing.

[ 06-15-2003, 16:28: Message edited by: Hot Core ]

I'll agree with Hot Core on this. PFLR does center the case with the bores axis better than even "partial neck sizing." This is because the spring back of the brass on the untouched neck of the brass is still always smaller than the chamber is in the neck area, and thus it still lays "somewhat" on the bottom of the neck in the chamber.

That said, I've gotton a bit better groups just neck sizing over all.

One problem with PFLR is that the springback qualities in brass are sometimes different from case to case depending on a few things. Once the dies are set up perfectly so only a slight resistance is felt upon chambering, this will often leave one case looser and still other cases on the tighter side. Sometimes you get a couple that are a real bitch to chamber even though the die does a good job on 90-95 percent of the other cases.

A reason the springback affect this is because when you FL size a case (squeeze the body back down) it also will move the shoulder forward, this is how you can get a fired case that came out of the chamber easily with .001-.002" headspace (rember springback) in a condition that it won't chamber if the die is "up" too far. Bringing the die down a hair at a time where it just starts to touch the shoulder and then pushes it back down far enough to account for the springback it will again encounter as you remove it from the die will get you the crush fit like HC talks about. You have to clean the case and chamber it each time you move the die down a hair to see when it just chambers with slight resistance in the end to accomplish this. Best to check three different cases each time you move the die down though, there is variance between cases and you'll have a better chance of getting it right with three. A Stoney Point Headspace gauge for measuring the datum point on the shoulder will le you know when the distance is growing and it isn't touching the shoulder yet and when it stats to stop and move the shoulder back down again. Smoking the shoulder with a candle will also help make sure you didn't end up away from the shoulder area in the chamber. It should remove all the soot when chambering.... if it isn't touching the soot won't have been touched.

Right now I'm forced into FL sizing on one rifle because the chamber is screwed, eccentric neck and such. PFLR of FLR will always keep runout to an absolute minimum where neck sizing lets it run wild if it starts.... NK sizing will not correct RO.

Good luck which ever you do...

Richard, not necessarily!! Extensive testing of this theory has produced inconclusive results!! Some people have had better accuracy with neck-sized-only brass, while others have had better results with fully resized cases. Additionally, others find that best results come from brass partially resized in a full-length die, like Ricciardelli mentioned. If full-length sizing, make sure to adjust your die so the case shoulder is not set back any!! Partial resizing is the best bet for this! I do not always full-length resize brass for hunting ammo, but if not, I make sure each partially resized case will go into the hunting rifle chamber easily before repriming and loading it.

[ 06-15-2003, 23:27: Message edited by: eldeguello ]

Hi Guys, I have an additional question along these lines, can I neck resize with my dies (RCBS Full length) or do I need to get a special "neck sizing" die? Thanks

I neck size exclusively for my Ruger No.1A in 7x57.

But I use a Wilson neck sizing die with an insert designed for my particular rifle and then use a Wilson straight line bullet seater. My brass lasts forever, to say the least (OK, up to 10 reloading dependin on the load).

I think that it is most important to have a concentric round, however you can achieve that, neck sizing or otherwise.

Ben Reinhardt
Pocatello, ID

yes you can use a flr die,back the die out to about the thickness of a dime between the shell holder and the die. now use a candle to smudge the neck and shoulder,try not to get the caseing to hot. now put the caseing in the press and lower the ram,when you remove the caseing you will see how far the die is on the neck by how much soot is removed,then just adjust your die until it is just touching the shoulder and you are set for neck sizing and also for partial full lenth resizing just adjust how far you want to push the shoulder back.hope this helps