As a general rule my best accuracy is attained with new brass as opposed to once fired or twice fired brass. This is the opposite of what I would expect to see. Anyone else seeing the same thing? Those of you getting better accuracy out of once or twice fired brass, what is your case preparation procedure?

jayloar - If this is the case, you need to be checking for runout, other common loading problems, proper bore/action alignment, and chamber dimension variations. Once fired (or more) brass is generally going to give you the most accurate results since it is fire formed to your chamber dimensions.

You might want to neck size only, trim all brass to the same length, and segregate cases by weight. There are a truck load of reloading gremlins to track down and resolve. Quality dies, reloading equipment, and measurement tools will help.

Unfortunately I don't have a concentricity gauge so measuring runout will be tough. If I've a runout problem, shouldn't it show itself in new brass as well as fired brass? As a side note, I do run new brass through the resizing die before loading it and the new brass shoots noticably better.

I'm curious as to the type of Rifle and brass you are using. I am getting much more accuracy from once fired (laupa)brass than I have from REM,WIN, or FED brass.

jayloar You can "see" if you have runout by rolling your loaded rounds on a flat smooth surface. If you see a lot of bullet tip wobble then you may have a problem. Not scientific but compare the new brass loads to the fired brass loads. What is the difference in accuracy between the new and fired brass loads? Are you neck or full length sizing the fired brass?

The rifle is a Tikka 243. The brass is Winchester. New brass loads usually shoot in the .45"-.75" range while once fired brass usually shoots in the .90" - 1.25" range. Still fine hunting accuracy but I'd like to be able to duplicate the wonderful performance from new brass. Currently I'm full length resizing. I started out by taking the full length sizing die and backing it out a turn but then chambering was stiff. It seems that I need to full length resize to get smooth chambering. I don't have a neck sizing die.

Try screwing the die in a 1/4 turn until it chambers smoothly for a partial resize.

Try indexing the cases the same way in the chamber each time ,ie orient the head stamp the same way when you chamber them when fired new and once fired. This may tell you if anything is not "square" with your rifle, barrel threads locking lug allignment etc. Just a thought. You might decrease the powder charge and try a slight crush fit of the bullet into the rifling, working back up to best accuracy and then try new and fired brass. I would not crush fit big game loads.

What is your case prep routine for fired brass?

New Brass:

I mic all the cases and pick the shortest within specification
As long as the mouths are not dinged up, I trim all the cases to a common length
If the mouth is bent, I run them over the expander ball only
I lightly de-burr mouth in & out
I de-burr the flash hole (inside) but I don�t uniform the primer pocket
Segregate brass into lots (40 rounds or so) by weight

Once Fired Brass:

I mic all the brass & note any changes in OAL
Clean out primer pocket with RCBS brush
Brush inside of the case mouth to remove powder
Clean all soot from case
If cases are very dirty they get 30 min in the tumbler, washed, and dried
If this is the 4th or 5th reloading, they are annealed
A very light coat of Imperial Sizing Wax and into the die

From your reply as to your techniques, it appears that you are not sizing the new brass, but are sizing the fired brass.

I'll bet that if you compared ALL measurements of your new brass (as well as case capacity and volumn) to your fired brass, you would see a significant difference between the two...

I am running the new brass through the full length resizing die before ever using it. I have taken measurements of new brass vs. fired brass vs. fired and resized brass and there are dimensional differences with the new brass smaller in all respects. I've tried various settings on the resizing die to try to improve my results but new brass just shoots better groups. I've seen this on my other rifles as well, Husquvarna 270, Remington 7mm Mag, Remington 280, Browning 300WSM. That's why I'm wondering about case preparation techniques. On the other side of the equation, maybe I've got a bum reloading press, I don't know. It's an RCBC Rockchucker that I've had for 20 years.

jaloar - If you are doing the same exact thing with new brass and once fired brass and the new brass is shooting smaller groups, then you gotta be looking at your gun for the cause of the problem. You may have a chamber problem, an action/bore alignment problem, etc, etc. Obviously something in your gun is inducing runout or significant alterations in your brass - that is IF all things are equal with your hand loads between your new and once fired brass.

Concentricity gages and micrometers can tell you a lot about what is going on.

Okay, since there are dimensional differences between the brass, then I would suggest that you first fireform all your brass before working up a load, and only neck size the brass if it is being fired in either a single shot or bolt gun.

You other choice of course, is to use nothing but new brass...

I've done quite a bit of load development with fire formed brass and I just don't get the accuracy of new brass. One thing I have noticed with fired brass is quite a lot of variation in the amount of force necessary to seat a bullet. Maybe the source of my problem lies there somewhere. Maybe I'll just use new brass for my hunting loads and use fire formed brass for practice loads. Hmmm.

Hello J

You may want to check the reloading dies for concentricity and so forth, and if multiple calibers yield similar results maybe the press as well. When I buy a box of new cartridges I generally shoot them up at paper just to get them ready to reload. I don't often use new cartridges or new brass for hunting as the accuracy from reloads is better. To be fair, ammunition the last few years seems to be better than in the old days.

Tom

I think in some cases once fired might be preferable.

[ 07-26-2002, 02:56: Message edited by: PC ]

In my 243win. i start with new win brass, sort to weight and do the flash hole, load and fire as it came from the factory. Then fl resize in rcbs and neck turn. Load and fire. This time i load with Redding bushing die, fl size every time, using no expander.The groups keep getting smaller.Imr4350 or imr 4831, Berger bullets, 68gr or 90gr match. CCI br-2 primer. 243winxb.