I'm sure this subject comes up from time to time, but I have a little electronic scale that I weigh my cast bullets on. I take a hard look at the base first and overall appearance and then weigh it and stand them up in a row. Most rifle calibers are gas check bases and I look for a good base to clamp a gas check on besides the grooves filling out well. Once in awhile I notice one that passes the lookover but seems to lean a little to one side when I stand it up on base.

I usually get a weight variance of say 2+ grns from high to low weight depending on bullet weight. Is this within most people standards when casting bullets or do you remelt the high and low weights and use within 1 grn weights? This is before any lubing or sizing and the weight will change once you do that especially if you add a gc. Thoughts?

Bill

Bill, pretty much same thing here on visual and the spread. But, for match only boolits, I weigh mine to .1 (point 1 as in one tenth) of a grain. May not be necessary, but psycologically it has me convinced I can shoot better in a match, and anything you can do to make the head better, is better by the time it reaches the trigger. Lately my spread on the RCBS 30-180-SP has been about a grain and a half, which is very good for me. Don't weigh handgun boolits, but if I played Bullseye, I certainly would. sundog

There seem to be a couple things that matter. One is mould maker. A high quality company like SAECO and RCBS will make moulds that produce bullets of pretty consistent weights. Lesser firms do not. Then there is the weight of the bullet. 500 grain bullets certainly have more variability than 180 ones. Kind of makes sense. I think too that it varies with alloy. Linotype bullets seem to have more consistent weights than lead ones.

Believe thinking it terms of percentages would be better than just weight. A 2gr. difference in a 50gr. bullet is a lot more drastic than 2gr. in a 500gr. bullet (10X more drastic)...the smaller the bullet, the more ruthless the sorting out process.

When I cast a bunch of 45/70 bullets (call it 400gr.), will sort them out into five groups. The ones that run +/- 1.5gr.are boxed up and labled "match". The ones that didn't make this cut and run from +1.5 to +4gr. are boxed and marked "practice + ". Run that in rever5se to get the boix marked "practice -". The ones that are visually good but outside of those limits are marked "plinking". The rest are tossed back into the pot.

Now keeping track of the casting shows that the worst weight vartiations happen (1) while the mold is colder than it's running heat, but dropping visually perfect bullets and (2) just after a fluxing.

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Sectioning some visually perfect bullets showed some with radial "cracks". These voids are more like center "tears" than bubbles, and I'd guess they happen when the outside solidifies well before the inside (as wuld happen with a mold too cold, but warm enough to cast a good looking bullet). Being on-center, these voids proably don't make much differnce.

Others have off-center "bubbles" (when you can find them...being off center, you lose patience before secioning the bullet that many times. These proably have a breater accuracy effect....but there is no way of telling what kind of void you have unless the off center one breaks the outer surface of the bullet.

Thanks for your replies and info. I don't now cast any bullets over 245grns but down to 80grns for a 6mm. several 30 caliber molds, a couple of 7mm and several handgun bullet molds. I have not been casting for any matches but still would like to have the most accurate bullets I can make.

I have never been able to cast a real consistant weight but work with different batches of alloy. I recently bought 50 lbs of lino that turned out to be mostly monotype 27-28 bhn, and am in the process of mixing that in with different ingots of ww's, range scrap, and lead sheeting. I'm not really set up to mix it all together, safely, and make all my alloy one mix. Seems I'm always firing up the turkey cooker to mix together two different batches but I guess I'll just have to work through it and get more consistent alloy mix.

I have a 10lb bottom pour Lee but wish it was bigger. I've tried using the Lyman casting ladle for my molds but that doesn't work as well for the smaller rifle bullets as it does for the heavier handgun bullets. I hope this influx of linotype will maybe make my cast bullets more consistent in weight.

Bill

I have been working on this weight variation question. Here's what I think I know:
All the visually perfect bullets properly cast during one session will weigh within half a grain of the average, or less; frequently within three-tenths of a grain. If they don't, you're doing something wrong.
This is without regard to the average weight of the bullet, based on my records that cover 7348 bullets, cast 111 per average session, with average bullet weights from 58 to 445 grains.
The average standard deviation of all sets of bullets cast was .139 grains.
For some reason the distribution of cast bullet weights is independant of average weight, a statistical situation that I don't understand. Like so many things.
This holds true where I don't stop for a break, or add alloy to the pot reducing the temperature a lot, or do anything else unusual-just a straightforward casting session.
When I weigh cast bullets, and I weigh almost every one, I throw out any beyond half a grain from the mean. There are perhaps two or three of these in an average set of 111 bullets cast.
joe b.

I'm not a match shooter, HOWEVER:

When doing comparison shooting to work up loads for a particular bullet, I have separated my bullets out into several weight groups -
The right on group
The slightly heavy group
The slightly light group
And set aside the ones that are extremely light or heavy.

Then I will use similar ones to compare powders, primers, etc.

When I find the combo of powder and bullets that works best, I just go ahead and use that combo with whatever weight variation I have of that same bullet and enjoy the day.

I think I'm guilty of not casting with a good steady pace and stopping to put cooled off sprues back into the melter besides using ingots of a little different batches. I had not thought about changing the temp of my pot when dumping in more ingots or sprues plus making little short casting runs. I usually knock mine out of mold into a pan with water and rags to raise the hardness a little but am careful that I have to turn away from the pot to get to the pan of water. Thanks

Bill