I am currently working up loads in my 416 and have been using virgin brass (FL sized, chamfered). I have a number of once-fired now and plan on FL sizing them when the time comes. Should I expect a difference in performance when I finish with the virgin brass and start going to the once-fired??

If they were fired in your rifle, then why full-length resize them? They now match your chamber.

I agree with Steve. If these are for use in ONE specific rifle, just neck-size them. Three ways to do this:



1) if you have a neck sizing die, obviously, just use that instead of the FL.



2) If you don't have a neck die, depending on the brand die you have, you may be able to drop the primer rod down far enough in the die to push-out the primer and size only the portion of the neck that will hold your bullet.



Just raise your FL die higher in your press until you are sizing the right length of the neck. Then futz with your primer rod depth to see if you can make it pop those buggers out. Another advantage to neck-sizing only - NO liquid lube and cleaning needed. I use fine powdered graphite or mica to "lube" the necks. One dip every other shell - no muss, no fuss, no cleaning needed.



3) Last resort - get a decapper die only and then neck size with your FL die in the higher position.



Now - if these are for use in different rifles, you gotta FL size them.



I neck size-only all my necked (and even one straightwall) cartridge that I reload.

I am just getting into this now with my loads, seems to me the more I FL size and fire my brass the worse the accuracy? My friend FL sizes the new brass then neck sizes 3 or 4 times then tosses the brass maybe this is the way to go. The one problem I see with neck sizing for hunting ammo is the possibility of a sticky extraction when you don't need it. I am playing with the idea of making a collet type FL sizing die with a neck mandrel, this would press the brass back into a concentric and likely accurate case.

Since your rifle is a 416, and I am assuming that you will be using it to hunt Buffalo etc. in which case I would definately full length all ammo..Feed and function take presidence over all else in big bore dangerous game rifles that are used at under 100 yards to kill big mean animals..

How long the brass lasts is of little importance, and accruacy isn't all that critical...New brass is best, once fired, full length resize once is next, the rest goes in the practice hopper.

Thanks Bob for your answer. I was just curious as to what differences would occur and would they be enough to worry over.

You and Ray both answered the question of why I was FL sizing.

If your FL die is set exactly right you will probably get better accuracy with full length sizing than with neck sizing plus you will have more dependable functioning.
The exact setting produces about .002 setback on the shoulder.
Neck sizing using a bushing type die that sizes only enough to give .001 to .002 neck tension will often improve accuracy. However this amount of neck tension is not appropriate for the handling received while hunting. Not good for a magazine rifle either.
Ed