case capacity

[kokomokid]

Anyone have an easy way to measure case capacity? I weigh my new brass and organize it according to weight, but think it would be best if I could measure and match acording to case capacity after it is fire formed.

[stubshaft]

Fill it with a fine grained powder or use water.

[felix]

For BR applications, sort cases by weight first, capacity second. Those most consistent in both measurements, use test firing with known accurate load. Those shot out of the group, place in a secondary pile. ... felix

[semtav]

I thought maybe it was just my poor drop tubing ability, but I have my cases all uniform weight and length, and after I load with powder (weighed) and put a wad on top, I measure the depth to the wad. It ranges from .220 to .260 with my current load. I keep all the .240 to .250 together since about 80% fall in that range,and use the rest for sighters/practice.

I need to figure out a way to keep them seperate and see if the same ones always result in the same powder heighth every time.

[stubshaft]

Are you screening your BP before you load it?

[semtav]

If you are talking to me, --- NO.

[John Boy]

Nominal capacity 45-70 = 79gn Read this article completely ... http://kwk.us/cases.html, 45-70

[kokomokid]

I have same thing as Semtav with a few cases that have higher wad column than the rest even after dumping and drop tubeing again. No I havent screened my 1 1/2 swiss powder as it looks uniform with no fines.

[Boz330]

I need to figure out a way to keep them seperate and see if the same ones always result in the same powder heighth every time.

Use different color magic markers on the bases. If you are like me be sure you write down which color is which.:bigsmyl2:

Bob

[montana_charlie]

I need to figure out a way to keep them seperate and see if the same ones always result in the same powder heighth every time.
For permanent marking, I file a notch in the edge of the rim. The notch is aligned with a character in the headstamp. If your headstamp said STARLINE, you would have eight different positions to place the notch...meaning you could designate eight different groups of cases.

Even if you didn't write down the significance of each notch position, you would still know that all of the cases with a notch at the 'L' are part of the same set.

Never had a notch get rubbed off or washed away when cleaning cases...

CM

[Lead pot]

Weighing brass will get you close but the volume the case will hold will vary even if the cases are the same weight. If you look at your cases even if they are from the same manufacture but different lots and made over several years time by adding to them the way the rim are cut, diameter thickness and the back cut groove depth, that little ring above the rim, will change the weight but not the inside volume.
With a black powder load the inside volume will make a difference on how the powder burns affecting the ES of the load.
Checking the inside volume of a case with water wont do it because the amount that stays behind, you will not get all out of it the same.
If you fire the brass thinking it will make it the same inside volume isn't necessary right because of the spring back. Some of the brass is harder depending on the alloy that came form the foundry like if some red or yellow brass was mixed in that batch, but you can get as close as possible to anneal your brass, fire it and clean it then use something that is uniform in dimensions like a fine ball powder that has been screened through two screens. Use what is in the second screen.

And after all that work is done it will all change as the brass gets stretched out after several shots fired and the brass gets trimmed for length again.

So Is it worth the effort?????:confused:

[Doc Highwall]

I would just weigh the cases that I know were from the same lot and call it quits. Just keep them as small of a spread as practical. Brass has a density of 8.44 and each one grain spread is equal to .1 grain of powder. Not taking into errors of scales a four grain tolerance of case weight = a .4 grain of powder and will affect smaller capacity cases more then a large capacity case.

[Lead pot]

Doc.

I pay more attention to the case neck variances in thickness along with the variances in compression with the same powder charge.

[semtav]

So Is it worth the effort?????:confused:

Yep !! unless one is satisfied with mediocre.

Last time I went out to practice at the gongs, I shot my .220 depth cases at the 300 yd target. they stayed on, but scattered all over the target.

Shot the others at the longer distances and got very good groups.

compression depth was .310, so it appears this load doesn't like that much compression.

I will continue to compare depths, but thats my initial observation.

[Lead pot]

Yep !! unless one is satisfied with mediocre.

There you go.

[Doc Highwall]

Lead pot, after case weight I check for neck thickness and file a notch on the rim on the thin side of the case. My cases had less then .001" variance and I placed the thick side down / notch up to help keep the bullet centered in the chamber. I also used a primer pocket uniformer from Sinclair to make all the primer pockets uniform. The variance in compressed powder heights I believe comes from not leaving the case long enough in the compression die.

[Lead pot]

Doc I think semtav is saying he gets the difference before he compresses.

[kokomokid]

Mediocre? Is that where you knock down 9 rams instead of 10?

[montana_charlie]

Doc I think semtav is saying he gets the difference before he compresses.
If that's where he sees the difference, I would forget the drop tube, and switch to a vibrator of some kind.

With cases that weigh the same (from the same lot, naturally) put charges in a bunch and vibrate them all...all at once...and see if there are differences in the settling after that.

CM

[RMulhern]

You may as well be out behind the barn playing with your whacker!

[GabbyM]

Here is my trick.

When running a batch of 5.56mm military surplus brass. After all the other sorting. I fill the cases held in a load block with my ball powder charge. Then use a light to visually inspect the powder column height. Several out of a fifty block will be off. Those are dumped out then placed in a glass jar with descant for storage as primed brass for making up M193 ball ammo. The good ones are boxed in fifty count boxes and as has been stated above. Cases that throw fliers are culled out into the Ball ammo jars. This culling process while firing is just one more reason it’s harder to run an auto rifle which slings your brass around.

I've some Norma brass I paid $40 per C back a few years ago. Now Norma is priced out of the market so shooters use Lapua. If you've a heavy rifle that is actually capable of shooting well enough to see the difference. Then spending money on the HQ brass is worth it. Even then it’s only worth it if you are shooting matches where one shot in fifty a quarter minuite off will cost you the day. I’ve the Norma brass in two calibers I shoot. Two hundred cases each which I only use for matches. It’s a lifetime supply. Currently popular is the Lapua or Hornady brass since the Norma is a dollar a piece.

[semtav]

loaded some more shells tonight. only had one in this batch that came in at .220 depth. rest were .250-.260. I dumped the one at .220 back out, and ran it back in thru the drop tube. It came out at .260. so my problem must be my drop tube incompetence. Will try the same next time to see if it follows same pattern.