Sorting cases by weight --- effect on accuracy?

[Bob 964]

I've heard & read that sorting cases by weight can significantly improve accuracy. Presumably, one looks for a consistent range of case weights. If this is this correct, what is an acceptable range of weight for .308 cases? At what point in the reloading process are the cases weighed? Any other tips/advice? Thanks.
Bob

 

[MitchAlsup]

Re: Sorting cases by weight --- effect on accuracy?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308_to_yuma</div><div class="ubbcode-body">I've heard & read that sorting cases by weight can significantly improve accuracy.</div></div>

I question the word "significantly". You might be able to eak out 0.01-to-0.05 MoA--that is just barely above the noise level of a really good shooter shooting a really excellent gun.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Presumably, one looks for a consistent range of case weights. If this is this correct, what is an acceptable range of weight for .308 cases?</div></div>

You weight all the cases (100) and sort them into bins where each bin is about as fine as you can weigh (0.1 gr). The actual weight (xx.x grains) does not mater, just the distribution. If you get a distribution where you have some heavy cases and some lighter cases but almost none in the middle, just separate the sets into distinct classes and use independently.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> At what point in the reloading process are the cases weighed? </div></div>

Cases are weighed durring brass preperation, after first sizing, trim, flash hole deburr, primer pocket uniforming (that is essentially the last step).

In my opinion, unless you are in a competition, its more work than necessary.

 

[Bob 964]

Re: Sorting cases by weight --- effect on accuracy?

Thanks Mitch.

 

[Gruff]

Re: Sorting cases by weight --- effect on accuracy?

I sort mine after all case prep is done. And I use Fred Sinclair's rule of thumb that cases should weigh within 2% of each other. For an example; Your cases have a mean weight of 150 grains. 150 x .02 equal 3 grains.

 

[Tripwire]

Re: Sorting cases by weight --- effect on accuracy?

I flirted with this for a while, a long time ago...

With all things right; as in same brass make, same lot # if that tickles your fancies, same trim length, same neck thickness, same primer pocket prep, same resizing method, etc, etc...then all that weight discrepancy between cases means is a varience in case capacity on the interior of the case.

What this translates into is a very slight varience in the pressure that drives the bullet. Within the same/same listed above, this varience is virtually meaningless if your powder charge has been determined with the OCW principles, which give you a tolerance range high or low that easily absorbs any miniscule difference in case capacity (weight).

Simple physics........

 

[Greg Langelius *]

Re: Sorting cases by weight --- effect on accuracy?

It helps some. Individual weight is one of the indicators that corresponds to individual case internal volume, so it makes a difference.

For BR shooting, where small differences are significant; it might definitely be worth doing. But actually measuring case volume, rather than weighing, would be the more effective measurement.

For less demanding shooting, which is (or should be, I think) what most of us do here, what I think of as 'practical' shooting; its value gets lost in the background noise of all the many other small variances that affect gross accuracy. You can do it, but if you can see a difference on the target that tracks directly to it, you're a better shooter than I am.

Many are.

To avoid losing my mind over miniscule details, I make a compact between myself and my ammo. If it can help me derive a consistent 1/2MOA of accuracy at 100yd, it's my friend.

If I'm doing better, I ask myself whether all the things I do for accuracy are really worth it. For me, handloading is an onerous chore that's unavoidable if I want to go on shooting. Anything that can be stricken from the 'do list' without endangering that 1/2 MOA accuracy standard is destined for history.

Greg

 

[CardiacKid]

Re: Sorting cases by weight --- effect on accuracy?

I'm in the same boat as Greg. I went out last weekend to fireform some new winchester brass and found that I shot a little tighter with the brand new cases that were varied in length (boat OAL and .001 here and there on the shoulder), weren't weighed or sorted, etc. than I did with my fully prepped ones a couple weeks ago. The result? I'm getting a little better at shooting - it's not my ammo at this point.

 

[Leaddog]

Re: Sorting cases by weight --- effect on accuracy?

I don't bother weighing. With .308's you have bigger fish to fry than worrying about this. Same with neck turning.

If you must weigh... you are better served by measuring case volume and not case weight. You do this by filling the case with alcohol, emptying it to a scale, and then weighing the liquid from your case. Weighing dry cases is futile. Case web variances will give you inconsistent weights.

 

[Clark]

Re: Sorting cases by weight --- effect on accuracy?

I did it 10 years ago, but I don't do it any more.

The difference is down in the noise, with my accuracy standards.


Any 5 shot group at 100 yards less than .5" is something to write home about for me.

I don't compete. I just shoot animals at long range.

But if you compete, there is no end to the silliness. Ever see a competition bass boat or competition bicycle?

 

[MAT4-82]

Re: Sorting cases by weight --- effect on accuracy?

I'm with Mr Langelius and several others above. This is Benchrest stuff which is of actual benefit to very few.Also unless you are using High end cases it will be a pretty frustrating process. If you and your equipment have the ability and the REAL NEED for 1/4 moa or better then you might want to consider it. Otherwise just put together a good reasonably assembled load using standard practice and quality components and don't worry until you honestly feel your ammo is detracting from your performance. Good luck

 

[Bob 964]

Re: Sorting cases by weight --- effect on accuracy?

Thanks everyone. I think I've heard what I need to hear. Thanks for taking the time to share your thoughts.
Bob

 

[5RWill]

Re: Sorting cases by weight --- effect on accuracy?

http://www.6mmbr.com/reloadingfroggy.html
<span style="font-weight: bold">"Q: Now we have some specific questions. First, do you weigh your brass or bullets?

No, I never weigh brass! I tried it and could find no real improvement in accuracy or velocity spreads. Weighing cases is a waste of time with good brass like Lapua. And I don't sort bullets by weight. I find with the consistent Sierra 142 MKs I shoot, any minute differences in bullet weight don't matter. Consistent neck tension and low run-out is way more important to accuracy."</span>

After reading this article i've decided i don't plan on weight sorting my brass anymore.