.223 Case weight. How would you sort these?

[mrgt350]

Sorted these cases in 1 gr increments. Quite a varation, 99.4 to 97.0 with 98.1-97.9 the three rows in the middle. Winchester brass.
Question is if looking for the best accuracy:

How would you sort these, ie: grains per group?
Will the accuracy vary between groups?
Will point of impact change between groups?

Thanks
Greg

[Rattler]

Good question. Are they all .223 Remington Brass or are their some 5.56x45 cases mixed in there?

[mrgt350]

The are all from the same lot and are Winchester Brass.

Greg

[Globemaster]

personally, I’ve never taken my reloading ‘hobby’ to this extreme; but I do know that a lot of the ‘High Power Match Shooters’ do! as they will sort-out any case that does not meet their stringent criteria for use in Match Tournament Shooting.

[mrgt350]

I was wondering if sorting the cases would make a difference like it does in the bolt action rifle.

Maybe these AR's are not accurate enough that it really makes a difference?????

Does anyone know if this is the case and it is worth the effort?

Thanks
Greg

[shootermcmillan]

ARs can be very accurate, they mostly dominate service rifle competitions with a few M1A holdouts. Case wieght can effect consistency of your rounds but would be toward the bottom of my list of concerns in reloading. If you are reloading for anything but the very topshelf match AR I think it'd be a waste of time. Just my opinion

[Evil_Lurker]

2.4 grs. isn't much of an extreme spread in case weight. Unless you're planning on shooting benchrest competition, and hand-weighing every powder charge, I'd just load the whole bunch as one batch.

It's not uncommon to see a run of brass that varies by 4 grs.

If you wanted to go to all the effort, it might tell you something.
I'm thinking you'll need a darn accurate gun, top notch bullets and a rock-solid rest to measure any difference, though.
Brass is heavy, and 4 gr. of brass doesn't translate into 4 gr. of extra case volume.
I'm shooting right at 1/2 MOA with Hornady factory loads, and they aren't particularly close in case weight, so I think it's a very minor factor.

I've been wrong before though.

[mrgt350]

Dtech do you have an opinion on this?

Greg

[Dtech]

As far as I can see, you haven't given enough information for me to give you any good advise.

What I mean is this: The brass casings that you are dealing with are swaged from s sheet of brass stock. They get drawn and formed over many steps. They may look the same, but there are many differences that will effect what/how they get sorted.

I don't do ANY sorting until I have full-length sized them all, trimmed them to length, uniformed and deburred the flash-hole and uniformed the primer pocket.

After all that is done, then, in theory, the differences in the weight between cases would be wall thickness. Without doing any of the detailing before hand, you are weighing cases that are not consistent in length, and many other ways.

All that being said, once you have your brass prep done, you probably won't see as much difference between cases, and I don't think you would be able to assess the difference in most AR-15's.

When I actually sort brass, I am more concerned with run-out in the case-walls. After I detail my brass, I measure the case-wall thickness just above the case-head. Cases that have .001" or less go into the "A" grade pile, and the case-heads are marked on the "thick side". Cases that have between .001" and .003" of run-out, go into the "B" grade pile. Anything over .003" of run-out are used for hunting or get sold off.

[mrgt350]

Mike,
The sorting I did was after detailing the brass as you described.

Question on your comment:
I am more concerned with run-out in the case-walls. After I detail my brass, I measure the case-wall thickness just above the case-head. Cases that have .001" or less go into the "A" grade pile, and the case-heads are marked on the "thick side". Cases that have between .001" and .003" of run-out, go into the "B" grade pile. Anything over .003" of run-out are used for hunting or get sold off.

Is runout and case wall thickness considered the same? How are you measruing this?

Thanks
Greg

[Dtech]

The term "run out" in this case is used to describe the difference between the thick and the thin side of the case.

I use a device made by NECO produce just for this measurement. It has a long mandrel on it that you slide inside of the case. You adjust it so that the "foot" on the mandrel runs where you want it to inside of the case. A dial-indicator runs on the outside of the case, directly above the foot of the mandrel. The indicator plunger is spaced away from the foot of the mandrel by the thickness of the brass. As you rotate the case, the indicator will rise and fall with the wall-thickness.

This is something that I always did with my long-range bolt-action ammunition. My 700 Remington bolt only has two lugs and when locked, they end up at 12 o'clock and 6 o'clock. When you fire a round, the neck blows out and seals itself against the inside of the chamber. Then the case will begin to blow out to fill the chamber. Much like a balloon, the case has thick areas and thin areas. As you begin to blow up a balloon, one area will start to fill first, then the rest will begin to stretch as more air is forced into the balloon. The same happens with the brass. As the case stretches, it stretches first on the thin side. The case turns into a "banana" in your chamber. As the case press against your bolt-face, if the thin side of the brass is against an unsupported side of the bolt, the bolt-face can actually tip slightly, and as you can imagine, degrade accuracy.

If you put the thin side of the case at 6 or 12 o'clock, then the pressure will be put directly onto a bolt-lug. Needless to say, the less run-out the better, but if you do orient your brass to a locking-lug, you can improve your accuracy.

On the AR, there are so many lugs that "where" a thin side would go is irrelevant.

[LarryA]

If looking for extreme accuracy, I would have to ask how would a bench rest shooter do it?

The folks who I have shot Highpower with only sorted cases by weight for 600 yards and beyond. But to what variation in weight, I do not know.