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.
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.
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.
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.
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.