My cure for case neck runout

teflondon100 · #1 10-14-11, 22:33

Being new to the forum I would like to say hello to all.
Browsing through post from the past I see some here who are trying to avoid runout. This is my loading procedure and has giving me great results. (0001 or less) I am sure a lot, if not all may find this practice a waste of time, and I am not real fond of the process myself...but it works. I shoot mostly bolt guns with tight neck chambers which eliminates this process. But when I load for any SAMI spec chamber this is what I do.
The example will be my AR-10 Noveske barrel. Lapua brass - neck turned down to 14 thousands. Not part of the process, just something I do.
A fired case neck measures right around .344
I full length size using a Redding S with a .342 bushing. I then move to my Redding neck sizing die with a .340 bushing. I change then to a .338 bushing. I then use a Sinclair expander mandrel lightly lubed. Keep in mind this is my AR-10 and it beats the necks up. For a bolt gun I skip this step. I then go back to the neck sizing with a .336 bushing then a .334 bushing, which gives me 2 thousands neck tension. I then check them all with a Sinclair concentric tool. I know this is a lot of steps and may seem foolish to many. I am curious to hear other ways. I have looked at the Hornady concentric gauge that fixes runout. But I wonder what effect it has on neck tension.

markm · #2 10-16-11, 10:55

Interesting. That is a lot of work. "They" say that .003-.004" and under doesn't impact accuracy.

My Redding Full length Bushing die usually runs .003 or under.

teflondon100 · #3 10-17-11, 07:53

It is a lot of work. What they say is probably right. I know I have checked plenty of factory match loads and found more than 5 thousands run out, and they seem to shoot lights out. I just want as much consistency as I can get. That's why I anneal cases, sort them by weight - trim the meplat and point bullets - sort them by weight and ogive and a lot of other pain staking, time consuming $hit. Is it worth it, I really don't know. Sometime it's only a 1/4 minute gain if that over not doing all this. I have seen plenty of times at 600 yard line a 1/4 minute was the difference between the 10 ring and the 9. Bottom line... I guess it gives me confidence in my loads. If I drop a few points, I blame me for not doing my job on the trigger.

markm · #4 10-17-11, 09:24

Cool. We've segregated some bad runout loads and shot them expecting horrible results. Usually the shoot just fine. Could be our monster bullet jump in our Rem 700 factory barrels.

I still go to great effort to minimize runout... and hand scale every powder charge, etc.

JStor · #5 10-18-11, 20:55

For Lapua brass in .308 Win. I first resize the fired brass with a Redding .339 bushing, then go to a .335 inch one for the final size. I'm using the Redding Competition neck die set. Redding recommends no more than .005 inch at a time for the sizing process so I stick with that. I use a .334 inch bushing for the final sizing if the brass is Winchester.

I combine the Lapua brass with CCI BR2 primers and Sierra 175 gr. Match Kings over 44.5 grs. of Varget for use in a Winchester 70 heavy barrelled Sharpshooter. Velocity runs 2680 to 2700 ft/sec. from the 24 inch barrel.