Ever asked a question and

[Travelor]

were not sure you wanted to know the answer?

Yesterday I cast bullets for my 32-40 using 24:1 lead at 725 degrees and a Saeco mold that I bottom poured. After culling the obviously flawed and underweight bullets, I had 128 bullets that resulted in the following:

93 bullets that weighed 205.16 grains +/- .2 grains
12 bullets that weighed .2 to .28 grains above the 93
15 bullets that weighed .3 to .38 grains above the 93
7 bullets that weighed .4 to .48 grains above the 93
1 bullet that weighed .54 grains above the 93

Why do the 35 bullets shown above weigh up to .5 grains more that above the vast majority of the other bullets? I can see no obvious differences in all 128 bullets.

Am I setting a weight variance standard too low or ?????????????? is causing the heavy bullets?

Posted on ASSRA Forum also.

[Mica_Hiebert]

so your less than a half a grain off from round to round? weigh some factory jacketed bullets and see how they fall, usualy 2 grains +/- or more. id say your being a little strict.

[bigolsmokebomb]

The only thing i could think that would happen is your alloy settled and seperated a little in the pot throughout your casting session. I still think that if all are within half a grain its well within spec. Ive had j bullets with more deviation than that and still put them more or less in the same jagged hole.

[buckshotshoey]

You were right. You asked....and now heres what you dont want to hear. If my boolits all cast within 1/2 grain, I would wonder if something was wrong! If mine are within 2 grains (45-70), im happy. My advice. .....load em, shoot em, dont even think twice about em. Anything within 2 or 3 grains in a .32 should be acceptable. If you were shooting a .17 or .22, you might want a little higher standard.

Do a shootoff. Load those matched weight boolits and some that are a couple of grains off. Ill bet you will ever notice a difference on paper.

[sparky45]

If you're like me when I'm casting, I'll dump the cut off sprue back into the pot while casting. I don't think it alters the mix that much, but might account for a couple of grain(s) difference.

[mdi]

Perhaps it's temp variations. Your 725 degree melt temp prolly varies +/- 10 degrees easily, and as mentioned by Sparky, temp. will drop if you add sprues and rejects. Then your mold temp can vary too, according to your casting speed. Someone mentioned alloy separation in the pot during a casting session. I dunno, but that sounds like "solid" theory (if in fact it does happen in a small, 20 lb pot)...

[DHDeal]

I see where you are loading for a rifle here. What yardage are you shooting them at, 200+?

My main experience is casting for a 2 BPCR's (45/70 and 40/65). My molds are all custom and I only dip. My casting sessions are usually 250 +/- bullets and I will have 2 different piles when I'm done. I will only accept a 1 grain variation between those piles (i.e. 400.0 to 400.9 grains). If I watch my temperature and dip technique, I rarely have any outside of that variation without any obvious defects.

I cannot say whether all of this extra pickyness is worth it, because I've never relaxed my standards. The bullets I cast and the ammo I load perform as I expect. I don't shoot hundreds of these in any one setting so my extra time is rewarded IMO.

Regarding your curiosity about why a few are heavier, I can only suppose alloy temperature and/or mold temperature (assuming you did not add alloy to the pot). There are many here that have more experience than I casting for target rifles, but I don't accept less than a certain variation of weight of my bullets for those rifles. ASSRA is a great place to ask this same question.

[rondog]

If I ever start weighing all my cast bullets, somebody please shoot me with one of them.....

[country gent]

On your bullet 1% variance is 2.05 grains your well with in that and for alot thats acceptable for consistant accuracy. Severl things can affect weight variations, mould temp, alloy tem, fill rate, pots slowly seperating or fluxing,and cadence. WHat your seeing may be a little tin antimony seperating as you session goes on, fluxing a little more often may help some but the mould temp and alloy temp come into the picture. A hot mould may fill and off gass better. I cast big long bullets 365 grn -550 grn I use a big ladle pot and ladle cast them running 2 moulds to maintain a consistant mould temp and cool down with out setting waiting. I dont pour a sprue but a ladle full of lead into the mopuld letting the excess run back into the pot. This keeps the bullets hot and molten a longer time allowing better fill out and gasses to be pushed out. WHen done this way the sprues are very consistant looking with little sucked in from them since the mould was filled and hot longer. You decide your quality control its your shooting. Thats part of what makes this hobby so appealing is that you decide whats good enough not a manufacturer somewhere that may or may not know your requirements.

[mart]

If I ever start weighing all my cast bullets, somebody please shoot me with one of them.....

+1. I doubt I could shoot well enough to discern the difference in even + 5 grains.

[runfiverun]

look at your sprue cuts.
that is the most obvious place.

if you do a long run of boolits and lay them out in order for a bell curve you'll see that as the mold settles down the weights will settle down and your curve will steepen out to the top.
the longer you hold the mold and alloy temp in the same range the taller that bell curve will be.
your little weight waffles back and forth will be the sprue tear or bump you leave behind.

[WALLNUTT]

Why would lead tin antimony alloy seperate?

[gwpercle]

When I got a new scale, several years ago, I started the weighing boolits thing , segregating , separating, wasting a lot of time , driving myself to distraction...JUST STOP IT !

Look at them, if the boolit has a perfect base , no visible flaws, no holes in base , well filled out...load them.
Unless you're shooting match for money or scores, you're just wasting your time.
I learned a long time ago not to ask questions about things I didn't need to know. A daughter will teach you real quick that ignorance about some facts are better than knowing all the details.
Gary

[Green Ghost]

I'm just a newbie, but, a couple of things that weren't already covered are:

If your using a multi-cavity mold, the cavities could be slightly different. Also when you pour the first cavity, the lead will be slightly cooler from sitting in the nozzle.

It could also be from varying your grip on the mold. Especially if you have a sticky alignment pin.

Hope this helps.

jerry

[edctexas]

Someone (maybe r5r) suggested that bottom caster should open the flow on the end of the sprue plate before letting the alloy go into the cavity. I tried this and it seemed to reduce the extremes of the distribution. But as another poster indicated, 1% is pretty good for larger boolits (say greater than 120 gr). Small boolits like 50-100 gr should be more uniform than 1% in my opinion.

Ed c

[scottfire1957]

I cast 'em, load 'em and shoot 'em. Nary weighed 'em.



Edit. Ya gotta remember, 1 grain is 1 7000th of a pound. It aint much. Certainly not enough for me to worry about.

[runfiverun]

if you look at the weight variance as a percentage of the total things come into perspective a little better.

try shooting 22 cal boolits at 2800 fps without weight sorting [into .1gr batches] and your gonna tear your hair out.
or try shooting 30 cal boolits over 2400 fps without holding a tolerance and removing the outlying weights and your gonna get the 4 in and 1 out groups frustrating you even further.
sometimes it matters.
3 grains in a 500gr boolit at 1200 fps,,,,,,, not so much.

[Bzcraig]

If I ever start weighing all my cast bullets, somebody please shoot me with one of them.....

Me too!

[Greg S]

I'd say they were casted later in the session after the tin lead alloy began to seperate hence the heavier bullets.:kidding:

"They didn't have an emotioncon stirrin' the pot!

[buckshotshoey]

if you look at the weight variance as a percentage of the total things come into perspective a little better.

try shooting 22 cal boolits at 2800 fps without weight sorting [into .1gr batches] and your gonna tear your hair out.
or try shooting 30 cal boolits over 2400 fps without holding a tolerance and removing the outlying weights and your gonna get the 4 in and 1 out groups frustrating you even further.
sometimes it matters.
3 grains in a 500gr boolit at 1200 fps,,,,,,, not so much.

I was shooting 77 grain Match Kings out of a National Match AR. They were way beyond a tenth of a grain variation and shot lights out! Maybe cast boolits are more finicky? I still dont think anyone can hold good enough to tell the difference of a half grain boolit variation..... even from a bench. Professional shooter maybe. It's more of a "confidence" thing, IMO.

[Chris C]

were not sure you wanted to know the answer?

Yesterday I cast bullets for my 32-40 using 24:1 lead at 725 degrees and a Saeco mold that I bottom poured. After culling the obviously flawed and underweight bullets, I had 128 bullets that resulted in the following:

93 bullets that weighed 205.16 grains +/- .2 grains
12 bullets that weighed .2 to .28 grains above the 93
15 bullets that weighed .3 to .38 grains above the 93
7 bullets that weighed .4 to .48 grains above the 93
1 bullet that weighed .54 grains above the 93

Why do the 35 bullets shown above weigh up to .5 grains more that above the vast majority of the other bullets? I can see no obvious differences in all 128 bullets.

Am I setting a weight variance standard too low or ?????????????? is causing the heavy bullets?

Posted on ASSRA Forum also.

I could easily explain the answer to your question, but you'd learn a whole lot more by reading this thread. It's a read that will take several cups of coffee to complete, but it's worth digesting every word.

http://castboolits.gunloads.com/showthread.php?269912-Consistency-applied (http://castboolits.gunloads.com/showthread.php?269912-Consistency-applied)

[runfiverun]

cast is a whole lot different than jacketed.
but the consistency applies there too, they might have shot lights out with a 1/2gr variation but think about how they would have shot without the variations.

a good bullet and a good barrel will always shoot well, but a better barrel and a better bullet will shoot better.
cast boolits don't have the luxury of being held together by a copper Band-Aid or having the air squoze out of the alloy like a core does.
they have voids and air bubbles and torn or bumpy sprue cuts the only way to find them is to weight sort them.
it might not matter a whole lot at 1700 fps or in the 44 mag levergun at 25yds.

but zip something through an 8 twist barrel and spin it 200-K rpm and you'll find out quickly what matters.

[Shiloh]

All are usable.
I'd keep the first three in one lot. That's just me.
You are less than 1/4th of 1% variance.

Shiloh

[fredj338]

A multi cav mold will offer some variation from bullet to bullet. Even though you are casting at a fixed temp, unlessit is PID controlled, some temp variation will occur as well as your temp, how hot the mold gets. This induces a bit more or less shrinkage. A 1/2gr variation in a 200gr bullet is quite good.

[buckshotshoey]

cast is a whole lot different than jacketed.
but the consistency applies there too, they might have shot lights out with a 1/2gr variation but think about how they would have shot without the variations.

a good bullet and a good barrel will always shoot well, but a better barrel and a better bullet will shoot better.
cast boolits don't have the luxury of being held together by a copper Band-Aid or having the air squoze out of the alloy like a core does.
they have voids and air bubbles and torn or bumpy sprue cuts the only way to find them is to weight sort them.
it might not matter a whole lot at 1700 fps or in the 44 mag levergun at 25yds.

but zip something through an 8 twist barrel and spin it 200-K rpm and you'll find out quickly what matters.

You do make valid points, but I still don't believe that most of us can see the results of a .2 grain difference in weight. Maybe one shooter in 10,000 will have the ability/rifle combination to see a difference on paper. If it gives you confidence in your shooting, then by all means, do what you have to do. It certainly cant hurt.

Here's a post that all of you have read recently. http://castboolits.gunloads.com/showthread.php?318136-The-virtues-of-bulky-and-quot-hard-to-measure-quot-powders. One would think that carefully weighed powder charges would tend to be more accurate
then metered charges. Not always the case apperently.

I was reminded of an article written by "Boots" Obermeyer....... Handloading For Match Rifles.......in 1994. I dug it up. It goes like this......


Quote...."Back in the old days,When we had just got around to loading from the rear end of the rifle (a joke), I carefully sorted some ammo for a Wednesday night practice. I had a box of 20 that everything was just perfect down to an equal weight of the assembled round. I shot a super score at 600 yards and being justly proud of it announced to everyone that I had shot this because of my total inspection and careful loads and I showed them the boxes sorted as to culls and best loads. Then I was shocked and still remember it well to this day. I had shot a box of culls by mistake. I thought the ammo I was shooting was the best and the only error would be me. I really bore down with full confidence in the ammo, but it wasn't the ammo that made the fine score. It was my shooting, the same thing that gave me bad scores. You constantly have to judge just how much gain there is in each of the loading details as to the time taken from practice." unquote

Ive always remembered this. I tend not to be so "ANUS" about my reloads, and instead concentrate on my shooting. Yes, I do some proper prep work on brass (consistent trim length, flash hole conditioning), and weigh my boolits, but just try to keep them within a few grains. With my rifle, and abilities, AND EYESIGHT, it just doesn't pay to be so anal about every little detail. Pick and choose the important ones, and spend the rest of your time practicing.

I will admit that when Boots talks about shooting a box of culls, those "culls" were probably better then factory ammo from the start. And he is referring to jacketed ammo, but it can also be applied to cast.

But each person has to determine for themselves what works best for them. I guess im from the school of practicing aim, hold, and trigger mechanics, instead of crafting the "perfect" ammo. Always worked for me. Got in top 10 percent in 2006 Camp Perry EIC match with this mindset.

[retread]

^^^ Me too!!
If I ever start weighing all my cast bullets, somebody please shoot me with one of them.....

[JohnH]

If I ever start weighing all my cast bullets, somebody please shoot me with one of them..... ^^^This

[44man]

Tried it once and shot worse with perfect weights.
Like Runfiverun said, maybe small boolits.