adverage weight spread

[zacharoo]

What is the normal difference in weights of cast bullets from the same pile of wheel weights. Say a cast run of 500 bullets. What should the difference in weight from the same mold on the same run?
Zacharoo

[kbstenberg]

  Zack a lot depends on the casters experience. The more experienced casters can have as little as .2 or .3 gr. But I tend to get a 2 gr variation (high to low) with my 44 cal molds. I have recently made a PID to help keep my melt at a more stable heat level. An I am going to start using a thermometer to keep my mold at a more stable temperature also.
  Kevin

[kbstenberg]

  Zach sorry i misread your name!!!!

[Czech_too]

I've been getting about .8 grains either way with most falling .4 grains.  Depending on the caliber, e.g. 22's, those at the extreme will go back into the pot.

[zacharoo]

The bullets are from a  270 gr.SAA with the Penta point insert. What should the spread be?

Zacharoo

[Czech_too]

Well, you could do .5 percent of the median weight which in this case would be 1.35 grains.  But, not to intentionally make this more complicated, the mould weight was calculated using #2 alloy most likely.  You're using WW's so the alloy weight is going to be slightly different.  Also, this is being used in a pistol and at what range? 
I would probably go 2.5 grains +/- of the average.

[Lloyd Smale]

Dont get to consered about it. As long as the bullet looks good and even if it doesnt but at least has a good lucking base it will proably shoot just fine. I used to weight bullets and toss out the odd ones and tossed out all the bullets with imperfections but my buddy got mad and said hed take them all. He showed me at his house one day why. Some pretty ugly bullets shot just as well at 25 yards as my hand selected ones. Only time your really going to notice them being effected is when the range gets out past a 100 yards. 44 250 grain bullets with a +or- 5 grain differnce will easily shoot one inch 25 yard groups if its a bullet your gun likes anyway.

[calvon]

Here's some results of my casting a nominal 140 grain 9mm bullet. I weighed them on an Ohaus balance beam scale. The bullets were made in a LBT mold.

[Terbltim]

I'm in full agreement with Lloyd, (maybe fuller.)
The subject of "consistency" in my cast bullets used to keep me awake at night.
After reading these forums for a couple years this topic would come up periodically.
Among the guys that have been doing this stuff for a long time, (like 20-30 years or more,) a few have actually gone to the trouble to try to find out just how "ugly" cast bullets can be before they're useless.
The answer is always quite surprising but I'll attempt to paraphrase it:
As long as the base is intact and the basic shape is complete its hard to cast bullets that don't give good performance.
You'll have to go to high-velocity and long range, (well over 100 yds,) before the differences begin to matter.
I primarily cast & shoot big-bore handgun & rifle bullets and they can get pretty ugly once you can let yourself relax about it.
I got wind of this a couple years ago and slooowly began to leave in the wrinkled bullets.
Now I don't bother weighing or worrying about wrinkles or much of anything any more.
I did and still do segregate the wrinkled bullets but I do load and shoot them and can't see any difference.
In a batch of 500 bullets I wouldn't blink at a weight-range of 7 or 8 grains, (that's 3.5 to 4 grains on either side of the expected weight.)
Now that I've relaxed about it all, I get a lot more "keepers" in each batch and neither the targets, the game nor the gunz can tell the difference. I sure can't.
Do a little experimenting and you'll begin to relax too.

[zacharoo]

I sorted out the bullets by weight. I took a mid range of 275 gr. those 275 and less went in one pile and the ones over 275 went in another. There were far more between 275 and 273 than over. The big pile I will use data for the 275 bullet and the other pile I will try to get data for a 280 grain bullet with same powder.  That way it will be close enough for me to feel good about the weights. They are the same cast lot but the weight is different. What should else can I do. I am not lo0king for bench rest  accuracy just for hunting with in say 40 to 45 yards, If the accuracy stays the same as it is now I won't worry . I will just separate at the same scale. For the 275 gr. bullet I am using Remington brass with WW LPP and am crimping with a LFC die. I am using 13 gr. of HS7 and WW 571 powder in a Ruger  Blackhawk. Haven't loaded a batch of the heaver bullets yet. Accuracy is good enough for me . I will try to find a load with same powder for the 280 gr. load. Any help with this powder combo will be appreciated!!!

Zacharoo

[Terbltim]

Sounds like you're making pretty consistent bullets and it looks [to me] like you're on your way to finding out how little concern you really have to give to these subjects.
The program you outlined will probably give exactly what you hope for.
I don't use those powders but I think you're in the right ballpark.
I doubt if you will be able to see any difference in the performance of any of those bullets except by [maybe] changing powder charges...that's the only thing that seems to matter with my gunz, uh, and I need a chronograph to be able to detect most of the differences.
Enjoy the shooting and the accumulated knowledge.

[stubshaft]

The only bullets that I weigh are those for 22 cartridges, and yes in an accurate rifle you can see the difference that .1gr makes.  For everything else they MAY get a cursory glance when lubing/sizing.