Total cartridge mass variation?

[NorthernBoy]

big boy steel 44mag
lee classic turret with double disc pro auto-disc.
How much variation in mass (gr) is acceptable/normal/safe between reloaded rounds?
I worked up 9 rounds and, just out of curiosity, checked the masses with a freshly calibrated digital scale. I found one round that was 342gr, that's 20.4gr lighter than the next closest. The remaining 8 rounds ran from 362.4 to 369.8gr (7.4 gr variation).
I ran another batch of 9 one step hotter. The maximum variation was 8gr.
Since the one round was significantly lighter, should that be a flag to not trust it?
Could the variation be due to the brass?
BTW, trying Win 296 with Hornady 225grain FTX and starline brass.

[Ojaileveraction]

In stead of measuring the mass of compleated rounds you would get more information from the variation in component parts.
Different weight cases may have different case capacity with a variation in pressures. Different bullet weights.. well tha'st obvious. Charge weights same thing.
At this point, you have no idea were that 7.4gr of variation comes from.
Benchrest shooters weight and group thier components and group them in like weights.

[JEBar]

I found one round that was 342gr, that's 20.4gr lighter than the next closest.

what weight powder charge were you loading .. .. with that round being so much lighter than the rest, I'd pull the bullet to make sure I didn't mess up and not add the powder

[clovishound]

My experience is that cases vary quite a bit. Trying to weigh completed rounds to identify variations in powder is an exercise in futility. Even brand new cases from a good manufacturer vary a good bit, although they are much closer than mixed headstamp range brass. I doubt a significant difference in brass weight will make much difference in accuracy in pistol calibers. Even a couple grains difference in bullet weight probably won't make much difference at the distances most of us shoot.

If you are looking for a check on your powder throws without weighing each one, you might consider a powder check die in your turret. I have one and it has saved my bacon a couple of times. Much easier, more sensitive than eyeballing each case and you don't have to rig a light, or remove the case from the turret press. The only down side is you can't use a separate crimp die without sizing/decapping in a separate operation.

[ditto1958]

My experience is that cases vary quite a bit. Trying to weigh completed rounds to identify variations in powder is an exercise in futility. Even brand new cases from a good manufacturer vary a good bit, although they are much closer than mixed headstamp range brass. I doubt a significant difference in brass weight will make much difference in accuracy in pistol calibers. Even a couple grains difference in bullet weight probably won't make much difference at the distances most of us shoot.

If you are looking for a check on your powder throws without weighing each one, you might consider a powder check die in your turret. I have one and it has saved my bacon a couple of times. Much easier, more sensitive than eyeballing each case and you don't have to rig a light, or remove the case from the turret press. The only down side is you can't use a separate crimp die without sizing/decapping in a separate operation.

I have found the same. Cases can vary quite a bit in weight. Bullets, too. It may say "158 grain" on the box, but expect them to vary a bit up or down.

[snell]

Accuracy nuts often weigh and segregate cases and bullets before loading. First, insure all the cases are the same headstamp. Weigh the cases from the same lot and separate by some set amount (say +- .1 gr) do the same for the bullets. Keeping the bullets within a +- range is easy to understand. The cases are weighed to try to keep internal volume consistent. While this has some influence in the target world I don't see it having any application to lever guns shooting pistol cartridges. But, if it gives you a warm fuzzy feeling you may actually shoot better.
Art

[JEBar]

Accuracy nuts often weigh and segregate cases and bullets before loading. First, insure all the cases are the same headstamp. Weigh the cases from the same lot and separate by some set amount (say +- .1 gr) do the same for the bullets. Keeping the bullets within a +- range is easy to understand. The cases are weighed to try to keep internal volume consistent. While this has some influence in the target world I don't see it having any application to lever guns shooting pistol cartridges. But, if it gives you a warm fuzzy feeling you may actually shoot better.
Art

I couldn't agree more .... early on I used to obsess on doing everything possible to produce identical bullets .... case trimming, trickling power charges, etc .... I'm not a precision, long range shooter .... I don't have that level of skill, never have, never will .... over time I've figured out that for the hunting I do, all that isn't necessary .... while I still load hunting ammo on our 50+ year old RCBS single stage press, I wouldn't get all worked up if the need arose to hunt with our practice ammo which we load on our Hornady multi stage press

[BigAl52]

Accuracy nuts often weigh and segregate cases and bullets before loading. First, insure all the cases are the same headstamp. Weigh the cases from the same lot and separate by some set amount (say +- .1 gr) do the same for the bullets. Keeping the bullets within a +- range is easy to understand. The cases are weighed to try to keep internal volume consistent. While this has some influence in the target world I don't see it having any application to lever guns shooting pistol cartridges. But, if it gives you a warm fuzzy feeling you may actually shoot better.
Art

I would also agree with one other comment. If you load for several calibers as I do I have better things to do like having time to go shoot. You can get yourself so rapped up in the all that weighing and sorting that there isnt anytime to enjoy the bullets your reloading. But to each there own putting bullets into the same hole just isnt my thing. If I wanted a bench gun I would have bought one. Al

[Squatch]

When in doubt pull it out!

This subject came up a while back when someone had a close call. Since then after I load I do a quick weigh of each cartridge just as a last check. I'm in no hurry and figure it can't hurt.

1st I load one at a time. I normally use a beam scale and a trickler. About every 5th-10th round I double check it on the digital scale. A couple of the powders I use are low fill and don't measure wonderfully in my powder measure. I always eyeball the case and then set a bullet in it.

I use Unique a good bit and in my 45/70 it is just a smidge of powder in the bottom of the case. 44 mag isn't much better. Easy to double load. A double of Unique wouldn't be pretty!

So I weighed some bullets and cases and found out that the variance wasn't that big if I use same headstamp cases.

So I now do a quick weigh once I load a box. I've quickly found most are real close. When one shows up way out of the norm I pull it and mark it with a sharpie. Way out of the norm for me is a difference of close to the powder charge weight. Say if charge is 8gr and one shows up 6gr heavy or light I'll pull it. So far out of several hundred I've loaded this year I've only pulled about 4 cartridges as suspect. They are on my bench and I haven't pulled the bullets yet so can't say if it was a bad charge or group of off weight components.

[NorthernBoy]

Excellent advice, folks. Thanks. Learning a bunch.