Have any of you guys seen the latest edition of Handloader magizine? Pretty interesting article on Myths of Handloading by John
Barsness. He goes on to say that a very common myth is that neck sizing makes the most cartridge and says that just ain't so.
He goes on to explain that with most neck sizing dies, you usually end up getting the neck out of round or not concentric with
the shoulder or what have you. He said that partial full length neck sizing is the ticket so you properly stablize the body of the
brass while neck sizing.

What do you guys think about that? What he said makes some sense. I don't know if I put much stock into alot of articles in
handloader, there groups are less than impressive. I have yet to see any guns tested with .5" groups at 100 yards. But makes for
interesting reading.

My first reaction was, "So the benchrest shooters are wrong?" Makes one think. For my personal ammo, I can't prove or disprove his theory. My 6.5-06AI shoots just as well full length resized as it does neck sized only, which is .5moa. My best group was full length sized and it was .084" at 100 yards and I only did that once (I'll call it luck). When I talked to the guys at Sierra Bullets, they said to try partial neck sizing to a bullet diameter only and let the unsized portion of the neck hold the case in the chamber evenly, or at least consistantly. That has worked somewhat by reducing groups from .5 to .4moa, but I would not do it for hunting ammo.

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Larry

bigcountry,

I have owned a lot of bench rest style rifles in calibers such as 6mm/06, 270, 7mm Rem and 300 Win and they have had standard chambers done with JGS reamers and reloaded with standard dies.

The following is what I have found in general, that is, some exceptions.

The most consistent accuracy has come when cases have been full length sized so as to produce about .003" headspace. Less is not good becuase press sring means that cases will zero headspace and others might have .001 or .002. Accuracy seems to go off once headspace goes bigger than about .006".

In general cases sized to produce a abut .003" headspace shoot better when the bullet is back from the rifling and neck sizing general shoots better when bullet is just near or just on the rifling.

When cases have about .003" headspace, if the bullet is seated too deep the open triangle groups occur. As the bullet is seated out the groups come down in size. Once the bullet is seated out too far the groups start to get flyers.

By the way, some of the best groups that come from bench rifles in 6mm PPC is when fireforing cases.

An advantage to having cases sized for a few thou headpsace is that you can usually get the same point of impact with bost new and resized cases.

One thing to remember about true bench guns, is that the chambers and dies are all concentric but this does not apply to ordinary rifles.

My experience has been that partial full length sizing is not the way to go. However, I have not altered seating depth when I have tried partil full lenght sizing and it may well requirea different seating depth than is the case for either neck sizing or full lenght sizing that produces a a few thou headspace.

One of the good things about ammo that is sized to produce a few thou headspace is that the seating depth that is best is commonly for the standard OAL for the caliber. In fact Hornadies usually shoot best when seated to the cannelure. This is good when considering magazine lenght.

One disadvantage to sizing that gets a few thou headspace is that the ammo can lose accuracy if kep for some time. This also applies to cases that you size today but don't load for sometime. This occurs because the most accuracy usually comes with the bullet seated back from the rifling and with time the brass loses neck tension and you also get variation in neck tension with time passing. When the bullet is back off the rifling neck tension is more critical to accuracy than whej the bullet just near or just on the rifling. New brass does not seem to sufferer from this.

Mike

Just because it is in a magazine, does not make it the truth. Been neck sizing for years and checking runout on a Sinclair concentricity gage. Just like thousands of other reloaders, I have never found a problem with this method.

I also set my sizing die up to just "bump" the shoulder back about 2/1000 of an inch.

In most cases where the body of the neck sizing die does not fit the fired case at all full length sizing is best. This has been tested and retested many times and the results published many times since I started reloading 38 years ago. As time goes on the test become more valid because the rifles are better and can better show the results. Of course if the tester does not really understand what is being tested or measured the results may be skewed. Regards, Bill.

Mike,

Very interesting post--especially the part about older rounds. I wonder if running older rounds through a Lee Factory Crimp die would "rejuvinate" the eveness of the neck tension.

Frankly, I like neck sizing because I'm lazy. A quick spin in the moly coated shot, and run the brass into the TiNi coated bushing, and VOILA. No messy lube, very little pressure, etc. To "clean" my brass I just twist the neck area with some steel wool, then I have an old bronze brush wrapped with steel wool attached to a bench mounted drill that cleans/polishes the inside of the neck. Now the neck is all clean and smooth and ready for sizing.

R