Gundigest

I know neck sizing dies are suppose to increase accuracy and I just ordered one for my 7x57 mauser, but I was wondering if they really do increase accuracy and by how much? I would like to hear from people who do use or have used them before.

PaulS

Gundigest,
I have used nothing but neck sizing dies for the last 20 years or so. In that time I have discarded a few shells but it has been less than 50. I found that my old 03A3 was good with factory rounds and full lenth resized cases and would shoot about 1.25 to 1.5 inch groups at 100 yards. I tried everything to get the groups down but it didn't happen until I learned a little secret. I began to lose cases with neck and case splits - that means they were being worked too much so I made a bit of a change. I started neck sizing and my groups actually got worse! I had to work the loads back up to get the improvement that I expected. I had to use more powder because the case volume was greater than it had been with full length sizing. Accuracy improved - a bit - I could group 1 to 1.25 inch groups at 100 yards. In a conversation with my smith he mentioned that a lot of the old surplus guns had a "generous" throat and that was about all you could expect from them without rechambering. So I did a little study and found a cheeper thing to try. I only sized the first 2/3 of the neck and left the rest to help center the front of the cartridge in the throat. It now routinely shoots groups of 5/8 inch and my cases last through more firings than I care to think about. I keep the pressures low and the velocities are below maximums too but I have enough velocity to shoot to within one inch of the point of aim out to 200 yards so I am happy.

PaulS

bigcountry

I bought two neck sizers and never will buy another. The redding competition Bushing neck sizer is ok since it supports the brass and keeps it centered. But the RCBS just makes things worse. I can get by with neck sizing a once fired formed piece of brass without much trouble, but more than that, the neck gets out of round easily. I do Partial Full length. But doing that, can be hit or miss. You really need to measure how your shoulder to make sure your not bumping it back, so setting up a partial full length and doing it consistently can be tough.

So for the sake of simplicity I mostly full length size as long as I am happy with my groups. And I am.

Solitary Man

I neck size all my brass. When they get too large to chamber any more (about 5 to 7 loadings) I buy a new batch. I'm getting great accuracy, but I think it goes beyond just neck sizing. I happen to believe that the concentricity (straightness) of my ammo has a great deal to do with my results.

I started out with the Redding S type bushing neck dies. They worked okay, but concentricity was never as good as I wanted it to be. So, after listening to some other guys, I decided to try the Lee collet neck die. All I can say is, I've been totally satisfied with this die. It's easier to use because you don't have to lube your cases, but more importantly it produces very straight ammo. Runout has been virtually non-existent in my loaded ammo since switching to this die. Of course the Co-Ax press and Redding competition seaters help a heck of a lot too. Another thing I like about the Lee die is that it works the case less than conventional dies, so it actually has three distinct advantages.

But back to your question about whether or not neck dies produce more accurate ammo. Maybe so, maybe not. I'd say they certainly have the potential to. But if your whole setup (press, sizing die and seating die) isn't capable of producing consistently straight ammo, I don't think you're going to see appreciable accuracy gains with any neck die.

Just my 2 cents.

bigcountry

Oops, I forgot about the collet die solitary brought up. I do use it extensively in my 308, and 270 rounds. Just don't make them for the 300RUM yet. One thing I can say is if my brass is fireforemed, my velocity spreads are much lower.