.243 case weights

[padd54]

So, I had a little time on my hands and decided to weigh the cases out of a new 100ct bag of Winchester cases for my 243win.

Here is how it turned out;

160.9-161.5gn = 19cases
161.6-162.2gn = 33cases
162.3-162.6gn = 27cases
162.7-163.5gn = 22cases

This gave a total of 101cases in a 100case bag. Smile

Is there enough deviation to matter, if so where would you draw the lines?

I have a Howa/Axiom that I want as accurate as possible and youth model for my grandson that just be to able to hit 2" at 100yrds.

Thanks for your help,

[TCPSTLSHTR]

I'm by no means an expert, but have you full length sized the cases and trimmed them all the same length and measured the neck thickness?
I'm sure there are probably a lot of other variables that may come in to play as well.

[padd54]

No, these are fresh out of the bag. I will check them again once I have them ready for loading.

I just thought this was interesting.

[TCPSTLSHTR]

Sorry to say, but in my experience, unless you buy match cases, what u got from production run brass, is not unusual....

[runfiverun]

161 to 163 isn't that bad at all.
i would size trim and cut primer pockets then weigh them.
then run them over a run out guage, after loading, and only use the ones with the least run out to them to shoot the small groups.
but if you only want 2" groups i would just trim them and load them i bet your rifle does better then 2" already.

[versifier]

IME, that variation is well within normal limits for commercial brass. (I see the same kind of variation in once fired mil match brass in -06 and .308, too. I have never weighed batches of commercial match brass to know if it is any more consistant.) The only time I bother weighing cases is if I have a rifle that is capable of .5MOA or better, and even then it depends on what I'm going to use them for. For practice or for hunting large game I won't bother. With my .22-250 I can still hit golf balls at 400yds on a good day with unsorted cases, but there is a measurable difference at that long range on paper when I do (1/4 to 3/8"). Many loaders separate all their cases by weight and doing so definitely will produce more consistant, and possibly more accurate ammo. Serious competitive match shooters often buy cases by the 1000's to put together 50 and 100rd boxes of similar weight. Bottom line is it can't hurt, and may help a little or a lot, but only if the rifle is accurate enough for the difference to show.

[Cap'n Caveman]

padd54,

If you want to get serious about this, I have found that segregating cases by weight is only a fraction of the amount of work necessary to produce one hole in the target.

Using virgin brass I start with annealing the neck and shoulder areas. Then the usual FL size. My next step is to machinine the flash holes to match each other, the primer pocket depths, and the inside of each flash hole too. I then turn the neck OD's to at least a 70% clean-up around the circumference, but all at the same thickness. All these tools are available at Sinclair. At this point I'll fireform them to fit the chamber with a load somewhere between medium and max. This is followed by cleaning, trimming to length and chamferring, one more hit on the primer pocket depth, and then finally segregating into a maximum of .1gr spread groups spread out on a large piece of paper. I'll take the 1gr spread consisting of the majority of the bell curve created by the individual groupings and cull out the rest on either side. I have plenty of freinds who want those for their shooting. The final OAL trim can account for .3gr, pocket machining .1gr, flash hole work another .1gr, neck turning as much as .9gr, for a grand total approaching 1.5gr. So a little bit here and there can add up in the original stamping / forming process of the brass.

There are other steps I take to tweak the loads beyond this, but this gets me the handfull of brass I'm looking for to make the difference. My primary objective is to begin the bullets flight as close to the center of the bore as possible, secondly by the most consistent launch I can give it by concentrating on pressure, ignition and all things that influence them. The rest is up to me and my sand bags.

Good shoot'n to all,
Cap'n Caveman

[padd54]

Thanks Cap'n, how much of a difference will you see at POI will a 2 grain spread in case weight, all things being equal?

[Cap'n Caveman]

padd54,

You will no doubt get tired of hearing this, but it is the truth. All guns are not created equal. Neither are shooters. "all things equal" assuming the firearm was bolted to the bench and couldn't move, yes 2gr would show a difference. The inconsistent neck wall thickness will play more into it than the mass. Most of todays powders used in that case will be forgiving enough to allow for the pressure differential getting your groups under that 2" mark you originally proposed. As versifier said, it can't hurt. You will never know until you try.

You can test this by weighing the complete cartrige assemblies. Find the extremes heavy and light, try a five shot group of each and see where the center of each group falls. I would not be surprised if you see a distinct difference.

[padd54]

Thanks again Cap'n. I was asking if you had tried this and what your results were. Sorry if I was unclear.

The 2' grouping was for my "Youth Model" at 100yrds.

I will be sighting and shooting 400yrds+ with my Howa/Axiom. It is currently at the gunsmiths for surface honing and trigger adjustment.

Thanks again for all the insights.
Ray