Do you neck turn new brass or fire form it first? How close do you sort brass by weight?

BB,

You only need to turn the necks of your brass if your chamber is tight necked. Turning necks for standard chamered rifles can cause your brass necks to crack.

Sorting brass by weight means you should get them as close to each other as you can.

We try shooting groups with brass that is exactly the same weight.

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saeed@ emirates.net.ae

www.accuratereloading.com

I quit neck turning for factory chambers. When I did I just set up to almost clean up the necks on most of the cases -- some still had old brass showing. I neck turn after the first firing and sizing when I do it at all.

I sort my 308 brass to the nearest grain. I shoot NRA, so I buy thousands of cases at a whack. This gives me several hundred per batch. The very light cases and very heavy cases get used as dummy rounds, fouling shots, or given to friends with full-auto "blasters" who don't worry about such things.

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Originally posted by BB:
Do you neck turn new brass or fire form it first? How close do you sort brass by weight?

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BB I think we got into the weight sorting in another post, it varies by how much the brass weights, a 308 would have bigger variances than a 223 some use 1% weight of case as "window" as for neck turning, the other post has it right, you don't get much good neck turning for a standard chamber with standard brass, but Lapua or Norma brass and forget about it or you need to do a "chamber cast" and find the actual diameter of you chamber, I had a batch of Winchester 220 Swift brass new in the bag that was too thick in the neck to shoot in my P64 Winchester and I had to neck turn them to shoot in a standard chamber they were .022 thick in neck walls vs. .015 for factory Norma and in this case had to be turned, for accurate varmitt loads a cleaning up of the neck variances by turning to a 80% clean neck material is a common pratice and helps in some guns and in others doesn't help at all! I use a Redding bushing die to size some cases and use a case wall thickness gauge by Sinclair/ RCBS NECO/ also make them, to find good cases without neck turning and this works better that turning a variable neck which usually means a variable case wall body thickness difference and the non turned cases in new good wall thickness cases give the best groups for me, but i turn the out of spec ones to save them and for fun shooting and save the best non turned for groups or counting! shots, this works for me and is similar to results in several manuals and gun "rags" I have studied, good luck and good shooting/hopefully in itty bitty groups!!!!!!

Except in a tight neck chamber I avoid neck turning like the plague. An additional negative creeps into the equation when you neck turn for a factory chamber. Usually the best clearance at the neck for a factory round is near .002" in order to get maximum accuracy. You can still attain good accuracy with clearances up to about .005" at the neck. When you neck turn you increase this clearance which works against you for extreme accuracy.

If the variance in the neck wall thickness is no more than about .0015" there is no need to neck turn and you'd get no benefit from doing so. If the brass is worse than that, get rid of it and start over again. Too much good brass is available with variances under this figure.

My approach to prepping cases is a bit different than Saeed's. What you are attempting to do in sorting brass by weight is to gain uniformity in the INTERNAL case. The case volume. Fire forming brass will alter external dimensions as well as the internal ones. The only things I do with new cases before fire forming is to uniform the primer pockets and run an expander in the case to round up the necks damaged by shipping or otherwise. AFTER fire forming I trim all cases to the shortest in the batch, uniform the flash holes, which is done after the trimming to insure consistent removal of the burrs in the interior, THEN sort by weight. Sorting before you do this will not give you uniformity of the internal volume because of differences in case length and irregularities around the flash hole.

I go one step further for cases prepped for extreme accuracy, and that is to cull cases which throw unexplained "flyers" from the group. These are marked at the range when it occurs. If they do it twice you can bet there is inconsistancy internally or in neck tension which is contributing to this. Bob

Many thanks for all the help. Better info here than anywhere else.

BB

Bob338 has nailed it pretty well.

I would add the following.

If you have a very good barrel mounted on a standard unaltered action, the bedding is right and the scope and mounts are OK and the load is right, you will get about 95% of the potential accuracy.

That is, if you put that same barrel on a "trued" action and have neck turned chamber, the improvement in accuacy will be very small.

Mike