Batching cases

phillh · Post by **phillh** » Fri Jul 04, 2014 7:27 pm

Hi all,

Question... If I wanted to batch weight 200 new cases what would be the most quickest/efficient way please?

I have done 100 before by weighing each case and filling in the weight on a spreadsheet, then putting the case on a numbered grid (100 squares on a piece of paper), then sorting the spreadsheet and finding the corresponding case from the grid.

Another thought was to weigh one case and zero the electronic scale, then put that in the middle of the table, then weighing the others and put them to the left or right depending if they are lighter or heavier. I am wanting to weigh to 0.1 gr difference.

Look forward to hearing what other ways there are.

Phill

shooter mcreid · Post by **shooter mcreid** » Fri Jul 04, 2014 8:16 pm

Phil,
I weigh a sample of say 10 which usually gives me an idea of the spread. I then start little piles in order from left to right with a piece of paper in front of the pile with the weight. After weighing the sorting is already done. Ill clip the stragglers on the end for club brass and then divide the rest into a heavy batch and light batch.

williada · Post by **williada** » Fri Jul 04, 2014 8:34 pm

Batching cases by weight is a good way of narrowing the range of cases into groups but you can further refine this by batching by volume. It may not be quick, but it is accurate. The weight of cases may well be the same, but their internal volumes can vary depending on where the metal is distributed in cases. There may be more metal in the web and less in the walls and over time with brass flow and trimming the distribution of metal will change again.

It’s a good idea to batch cases after they have been fired a couple of times and been trimmed etc. and resized for correct headspace. This takes the brass spring back into account. Leave the primer in and place the shell on the scale. Use a syringe and fill it with water and fill the case carefully leaving a slightly convex drop of water on the top of the neck as the water forms the meniscus. Should you spill water use the corner of a tissue to absorb it and then take your reading. With practise you can get through quite a few cases in no time.

If you want to batch further take your bolt firing pin and spring out and insert the case into the chamber (assuming you have not bumped the shoulder back more than 0.0005”-0.001” and particularly if you neck size only or use a Lee collet die) and batch cases by the feel of the bolt closing on them.

ned kelly · Post by **ned kelly** » Fri Jul 04, 2014 9:32 pm

G'day all,
I'd rather go to the dentist for a root canal procedure. :shock:

Enjoy!
Cheerio Ned

OuttaAmmo · Post by **OuttaAmmo** » Fri Jul 04, 2014 10:54 pm

ned kelly wrote:G'day all,
I'd rather go to the dentist for a root canal procedure.
Enjoy!
Cheerio Ned

Haha! I'm thinking the same Ned

Tim L · Post by **Tim L** » Sat Jul 05, 2014 7:42 am

I have an A3 piece of graph paper. Weigh a few cases, 10-20, just quickly to get an idea of the median and jot down weights in half grain increments (you can do 0.1 if you like) along the X axis. Then just weigh the cases and place them above their corresponding weight. You end up with a histogram made from the cases. Chuck the ones at either end, then put the remaining in boxes. I put the lightest in the front left hole and work to the right, then up to the next row and so on. That's then their position and that's the order they are shot in.

ned kelly · Post by **ned kelly** » Sat Jul 05, 2014 8:34 am

G'day all,
personally having weighed PPC cases for the first several years in competition, I one day used all the culled "weird" cases and won the local 200yd event. From that day in BR and F class I've found no reason to weigh cases.
I figure you may have two cases of wildly different weights but the same volume, so why weigh? It doesn't prove much. Measuring neck wall thickness and sorting would, that's why I neck turn.
I do however, uniform primer pockets and clean with the same tool for each reload, I've deburred the flash hole, and neck turn for both a no turn neck, tight neck and factory chambers.
The reasons are for consistent ignition and bullet grip. These two factors are much more critical than case weight and order of shooting them.
The other critical factors are the build tolerances and quality of the rifle and it individual components, the position of the bullet in relation to the rifling lands, and exactly the same amount of powder.
There may be some merit in batching bullets but I'd rather buy a proven bullet and load straight from the box.
Next is the practice side of things, in all conditions and as many ranges and venues as you can.
A ton of experience beats consistent case weights. And gives you the experience and knowledge to know whether a technique is worth the effort.
Just my 2 cents but I am yet to be convinced of the value for case weighing and batching.
FWIW, I spent most of my working career building and maintaining aircraft, working to 10ths of a thou tolerances. So I figure this might have some relevance.
Hope this helps.
PS I'd still prefer the root canal procedure to weighing cases! Far better to read a good book on the technical side of reloading, shooting and mental training.
Cheerio Ned

Barry Davies · Post by **Barry Davies** » Sat Jul 05, 2014 9:18 am

Been there done that and after MANY rounds fired trying to prove that case weighing ( and volume checking ) was the answer, finally gave it away and utilised the time doing something more productive.
Spot on Ned.

Post by **AlanF** » Sat Jul 05, 2014 9:42 am

It has been experimentally shown that velocity does vary with case weight. It is one of many things that the diligent LONG RANGE shooter takes seriously (you can get away with much larger velocity spreads at 200 yards than at 1000). The more things you can do to reduce velocity variation, the less vertical fliers you'll get. Fliers are generally the result of several things happening to cause an error in one direction e.g. a low velocity flier could be mostly caused by the accumulated affect of low charge weight, less neck tension, higher case volume (indicated by low case weight), and poor ignition (many causes). With case weights, I weigh every case into numbered loading blocks, using a spreadsheet as per the first post, then sort by weight. I usually end up with 3 batches of cases, with about 60 to 70% of them in the middle batch. The full process takes about half an hour for 200 cases. It has no other cost than keeping the batches separate. Williada takes it further with the water capacity sort. I'm sure it will result in better ammunition - whether the amount of improvement is worth the effort is the question. The individual shooter makes their own assessment on that. FWIW I don't anneal, neck turn, or clean cases internally, but I do weight sort new cases, at least check base to ogive consistency of projectile batches, moly all projectiles, and try to weigh powder to the nearest kernel.

KHGS · Post by **KHGS** » Sat Jul 05, 2014 9:47 am

I agree with Ned & Barry, use quality brass & forget it, not important with cases of over 40 grains of working powder charge. I use collet neck dies & do not bother with neck turning for "F" class. I clean & uniform primer pockets, I also clean the necks inside & out. I do not tumble cases, I don't want anything in my cases except powder & seated bullets. My views for what they are worth.

Keith H.

Longranger · Post by **Longranger** » Sat Jul 05, 2014 10:04 am

I know every little bit helps but I agree with Keith on this. An O/C disorder doesn't help with your shooting.

What's next, measuring gas flow through the flashhole?

phillh · Post by **phillh** » Sat Jul 05, 2014 10:22 am

Thanks for all your responses. As expected they are varied from one extreme to the next. I'm going to weight them for my piece of mind, something else I don't have to worry about in the BIG picture of shooting.

I thought the idea with weighing the cases was basically telling you the difference in internal volume. I know you don't know what that is using that method, but don't all cases have the same in external sizes/dimensions, so therefore any change in weight is due to brass thickness variations, so therefore a difference in case volume?

Phill

Tim L · Post by **Tim L** » Sat Jul 05, 2014 10:58 am

phillh wrote:Thanks for all your responses. As expected they are varied from one extreme to the next. I'm going to weight them for my piece of mind, something else I don't have to worry about in the BIG picture of shooting.

I thought the idea with weighing the cases was basically telling you the difference in internal volume. I know you don't know what that is using that method, but don't all cases have the same in external sizes/dimensions, so therefore any change in weight is due to brass thickness variations, so therefore a difference in case volume?

Phill

The variation would come if the extra/less brass was at the neck/shoulder which doesn't hold any powder.
In saying that is becomes apparent that filling the case (including the neck) with water isn't actually going to differentiate either,,,,, So weighing is probably as good as measuring, and a whole lot quicker.
I'm not convinced weighing the brass offers much other than to ID the "out of spec" cases. Brass is pretty heavy/dense, how much volume is 0.1gn of brass? I only do it "just in case" and it provides the final opportunity to check the brass before it goes into the loading process.
Thinking about it I do quite a lot of "just in case" work

aaronraad · Post by **aaronraad** » Sat Jul 05, 2014 12:48 pm

Longranger wrote:I know every little bit helps but I agree with Keith on this. An O/C disorder doesn't help with your shooting.

What's next, measuring gas flow through the flashhole?

Must come up with a air gauging system for brass... :idea:

Tim L · Post by **Tim L** » Sat Jul 05, 2014 1:53 pm

Longranger wrote:I know every little bit helps but I agree with Keith on this. An O/C disorder doesn't help with your shooting.

What's next, measuring gas flow through the flashhole?

I find it's more accurate using a liquid rather than gas.
A Number 7 20ml measuring cylinder has an ID of 12.5mm, (probably half inch but good enough anyway) so ideal for the 308 family. Fill it with metho and lower the case to the 20ml mark then let it go. Time the drop and expand the primer hole or discard the brass accordingly.

I suppose you could just fill it to a point below the 20ml mark and use it to measure the volume of brass and batch that way, it would save weighing it afterwards.