Neck sizing vs Full Length resizing

[luvdemcoues]

Hey all you More Knowledgeable People Than Me out there, I have a quick question about reloading. When I was first taught about reloading, I was told that Neck Sizing is better than Full Length Sizing because it is more acurate. I am reloading for a bolt action 270 WSM. I cannot find the Neck Sizing dies anywhere. Plenty of the full length dies. How much of a difference does the neck sizing make compared to the full lenth sizing. I currently have the RCBS Full Length Sizing Dies. Thanks for the help.

Josh

[Red Rabbit]

After a while of neck sizing only, you may have to partial or full-length resize if the case becomes to hard to close the bolt on.

If you full length resize, push the shoulder back each time and there is a some headspace that the case stretched into when fired, you may end up with a case separation above the case web. Full length sizing may work-harden the brass and cause you to anneal the brass.

I have normally done a partial resize with full length dies. I turn the dies in just enough so the shoulder is touched, but not bumped back.

One thought is that neck sizing just to the base of the bullet contact, and not the entire neck, will promote accuarcy by helping align the cartridge in the chamber.

I d not know if you would see a difference in accuracy in neck vs partial vs full-length resizing for a factory hunting rifle.

[matthewp45]

I only use the full length resizers and have never had any problems with accuracy at all. When you set the die just make sure it is set to resize to the bottom of the neck and not down on the shoulder. It is easy to tell by the ring left by the resizing oil.

[308Nut]

I cannot say that neck sized loads are really any better than FL sized loads so long as they were reloaded properly. Now for a benchrest shooter where winning and loosing is seperated by a few thousandths of an inch, NS may be a tad better however it is not going to make a 1 MOA rifle a 1/2 MOA rifle. The reason alot of guys NS only is because the brass can last longer than if you expand and resize the brass every time. When you do that, 2 things happen. 1, the brass moves forward causing a weak spot towards the head of the case (near the base) and the brass becomes 'work hardened' which makes the brass much more brittle. NS only is not always the answer either. In most factory SAAMI spec chambers, the brass expands quite a bit and only contracts back a tiny bit during the first firing. When you neck size only and shoot again, that brass is already stressed and has lost some of it's 'spring back' properties. After a few firings you will notice that the cases come out and chambers very tightly. So really, for a factory cut chamber, pick one and replace your brass often. For a very snug match or BR chamber, FL sizing or NS work about the same. With a very snug chamber, the brass never expands much at all and springs back to dang near specs on it's own. This eliminates the stress on the brass which keeps it springing back to shape with every shot. To neck size only is a good idea in this case because it takes nearly forever for a case to become 'sticky'.

 

If you have FL dies available, use them. Reload the cases a few times and toss them. Dont forget, when you use FL dies, TRIM your necks!!!! Otherwise, the case can be too long and crimp the bullet when the bolt closes and it gets forced somewhere it doesnt belong. Too much pressure will result.

 

RR is spot one here with the shoulder. The die should touch it or bump it NO MORE than .0005" That is 1/2 of one thousandths of an inch. Major issues will result if you bump the shoulder back too much.

[Benbrown]

With good dies, there is no accuracy advantage to neck sizing vs. full length resizing. As RR noted, you can neck size using a full length die--just stop when the die contacts the shoulder. Some folks will back off a half-turn or so from this point. The advantage of neck sizing is that the brass lasts longer, as all you are working is the neck. If you shoot a lot, neck sizing will make a difference in case life and how much brass you go through. I have .30-06 cases that are almost 40 years old that have been loaded 20-25 times. You do need to anneal the cases necks every 8-10 loadings, as they will get brittle and crack without it.

 

With the WSM cases, you get much the same advantage one gets with the Ackley Improved cases--there is not a lot of case stretching and you need to full length resize only occasionally. When loading for a hunt, you should run every loaded round through your rifle to make sure that each one will feed and chamber properly. Over the years, I have come to neck size when working up loads and shooting for practice, but I full length resize brass that will be loaded for hunting. Nothing is more aggravating that finding that the round on top of the stack in the magazine will not chamber fully, especially when you you have a big buck or a big bull in sight.