Weighing loaded cartridges

[Bugs100]

I was loading 45acp's when some thing hit the floor, I figured a collect rolled of the bench.. I kept pulling the handle and almost finished the 5 in the shell plate when I noticed one of them didn't have any powder in it.

I got off the stool and searched the floor and found the pistol powder sleeve had fallen out of the powder measure and the retaining clip had broken.

Now I have 3-4 duds mixed in to the 50 or so loaded shells.

I said this to the guy at Hornady and he said weigh them.

That sounds tempting seeing as they all should be the same weight except the for the ones with no powder but I'm doubtfull.

Any one ever try this?

 

[Lugnut]

Well... I'm not saying what I'd do.. but a couple things would sway me. What is the variation of the brass you're using? If it's the same mfr of brass that would make me feel better. What is the variation of the bullets? What is the load weight? If you don't get more than a grain or so from the bullets and brass (each) and you load is say 5gr. I might be tempted to weigh them. Remove bullet from lightest is another option. Either way.. if you decided to use these... it would be slow shooting only if I were you.

 

[Bugs100]

There all Remington with Hornady 230 grs and 5.2grs of W231. My scale was real expensize and very accurate. I think I'm going to give it a try and see how many come up light.

Then pull those if any have powder in them 'll have to pull them all. Either way I think I'm going to have to load them one at a time and keep my hammer and rod close.

 

[Finalygotabeltfed]

Pull them all.

There could be variations in bullet weights and brass weights that could be very close to your charge weight.

You will waste more time trying to weigh them and having doubtful results than pulling them and making sure of your results.

Pulling 50 pistol cartridges is nothing......try 4000 .308 rifle cartridges because of a powder problem.

 

[jhrosier]

Bugs,
Swaged or jacketed bullets, primers and cases are all pretty uniform in weight.
You shouldn't have any problem spotting the light ones.
Start by weighing an unprimed case, bullet and new primer together.
Compare this weight with a known good cartridge that you loaded.
When you weigh the rest of them, your scale will clearly indicate the light ones.
This sort of thing happens to every handloader at least once.

 

[highlander]

I've done it using my own cast bullets variation was small and i found the cases with no powder no problem

 

[GTOShootr]

I recently did the same thing but had many more rounds to check. Weighing them works and didn't take long at all.

 

[KMaurer]

If you want to verify that weighing them will work, first weigh a bunch of the bullets and primed cases (or cases and primers separately) to see what sort of variation you're likely to see. If it looks as if the total is well below the 5.2 grain powder loads you're using, then you should be good using this approach; if it's anywhere close to the powder weight, don't take the chance.

Ken

 

[Bugs100]

Out of 50, 8 came up under 320 grs. So that cut down the amount to be pulled. The lowest weight ranged from 315.1 to 319.9. So I'm going to pull all those.

If the one that weighs 319.9 has no powder I'm going to work my way up through the other ones.

 

[RKG]

I'm not sure that weighing loaded rounds would detect the lack of powder, so here's what I'd do:

Divide your 50-odd rounds into 8 more or less evenly sized groups. If, as you assert, the total number of duds is 3 or 4, this guarantees that at least four of your groups will not contain a dud.

For each group, compute the average and standard deviation of the weights.

Discard the four lowest average groups.

For the remaining four groups, if the 2 x SD < 2.5 gr, then I'd call the method valid, with a 95% confidence interval.

 

[adweisbe]

50 loaded rounds or $5 for me. I might not even take the time to weigh them. Maybe just chuck em or pull em?

 

[KMaurer]

Divide your 50-odd rounds into 8 more or less evenly sized groups. If, as you assert, the total number of duds is 3 or 4, this guarantees that at least four of your groups will not contain a dud.

????? How would 3 duds get distributed across 4 groups, and since the average group size is going to around 7, why couldn't all 3-4 duds end up in a single group? After all, with 4 duds out of 56 rounds the odds of them all ending up in the same group would be about 0.06%, compared to about 46% that they would all end up in four separate groups.

Ken

 

[jkelly]

????? How would 3 duds get distributed across 4 groups,…?---KMauer

What RKG said was:
“If…the total number of duds is 3 or 4, this guarantees that AT LEAST FOUR of your groups will NOT contain a dud.

He did not say: “…that AT LEAST FOUR of your groups WILL contain a dud.

If there are at least 8 groups then RKG made a “TRUE” statement. You can not spread 3 or 4 duds over more then 3 or 4 groups which leaves “at least” 4 of the 8 groups with out duds.

Not knowing the components involved or exactly how the pistol powder sleeve falling out of the powder measure affected the powder throw I couldn’t comment on the rest of RKG’s post.


Respectfully,

jkelly

 

[RKG]

I shouldn't have been so cryptic (I was in a bit of a hurry, I guess): the test I described is a more or less standard test for the sensitivity of a test, based on MilSpec 105D, with the confidence interval set at 95/95 (and a dash of extra conservatism implied by the use of 2.5 gr. as the cut-off, versus the 5.6 gr. stated weight of the questioned powder charge).

This is a pretty standard technique.

The test I described is not a test for the duds, but a test to tell whether weighing the loaded rounds will detect the duds.