Is it something that i am doing wrong?

[mattbowen]

Ok here is the question; I casted about 250 boolits and started weighing them and found that the weight difference between them is from 401.5 to 404.9. Is there something that I am doing wrong or is that normal. The mold that I am using is a Lee 458-405 HBFP and all the bullets look like they were filled out.

Thanks in advance

Matt:confused::confused:

[southpaw]

You are less than one percent variation. I would say that you are doing pretty darn good.

Jerry Jr.

[mattbowen]

Thanks' I guess that I am just use to jacked being with in a 1/4 to 1/2 grain.
Thanks again I thought that i was doing something wrong.

Thanks again

Matt

[44MAG#1]

Unless you are a caster of the extreme nature you will get some variation.
One way to tell if the variation hurts is to test them to your satisfaction against some know accurately cast bullets.
I doubt that you will be able to tell any difference in them over a 5 round 5 group test for the ones that vary that much and the one that vary very little.
Most of the mumblings about weight variations are from the guys looking for that elusive one hole group.
My opinion only one must remember.

[mold maker]

If the variation bothers you, load them in groups of like weight.
That way your POI at long distance might improve.

[mattbowen]

Thanks again guys, MM that what I did since I am a first time caster I was wondering if I was doing something wrong. 44 with my match grade rounds is when I try for the tights groups but I am casting these to hunt with 1" to 2" groups is good enough for the distance I am hunting, if I am going to go beyond the 100yd mark I will use one of my scoped rifles.

Thanks again.

Matt

[seanhagerty]

The make up of your casting lead will cause the weights to vary. If you have a higher percentage of nonlead components you will see lighter bullets. Using pure lead, you will see heavier bullets.

I just cast for good fill out and and sharp edges of the grooves and am happy. The weight will take care of itself.

Sean

[mattbowen]

Thanks again

Matt

[JCherry]

Matt,

Weight variation can be caused by not keeping your melt temperature even. Get a thermometer and keep your melt as close to the same temperature as possible as you are casting.

I find that using a lead dipper gives me more consistant weights.

If your timing, as you cast, is interupted that can also give variations in bullet weight as your mold may cool down a bit or going too fast can cause it to heat up.

Your bullet hanging up as you cast or slowing down your tempo can also cause variations.

Not closing you mold completely can cause some bullets to be overweight.

I'm casting the 500 grain Lee spitzer bullet out of wheel weights and my widest variations normally run, at the worst, plus or minus 1.3 grains. Normally I run plus or minus .5 grains variation (i.e. 494.5 to 493.4). I like to run my melt at about 800 degrees.

I have not used the Hollow base mold so that might be some of the problem especially if it hangs up sometimes.

Hope i've been of some help.

Have Fun,

JCherry

[mattbowen]

J;
Thanks for the info, I use a dipper and I have a thermometer and and have been running my temp at about 700 to 720. The first batch I casted (and the ones I am loading now and waid) were done in mid 40 degree temps and the second batch was cast in the low 60s. from what you were saying that might have been what caused the variations in the weights.

Thanks again

Matt

[JCherry]

Matt,

Sounds like you are headed the right direction. Just keep trying for consistancy in what you are doing.

Have Fun,

JCherry

[mattbowen]

All I can say is I LOVE IT!!!!!!!!!

[Bret4207]

Sounds to me like you're doing great! Consistency is the key in getting your castings as close to alike as possible. That and a good hot mould, a decent alloy and the eye to spot issues and alter things on the fly will all help.

Just for kicks, weigh out 3.0 gr of your alloy and see how much that really is to look at. Might put things in perspective. I'm betting it'll be something the size of a piece of #6 shot or maybe smaller. A small lump or divot on the base can cause that much change on a large boolit like you're casting.

[mattbowen]

Bret;
Thanks for the reply, just out of curiosity I weighed one bullet and it weighed 402.9gr and I took my deburring tool and trimmed a slight bit off from around the hollow base and it went down to 402.0 and it wasn't a full 360 degree turn. I don't know if that will effect the bullets balance any but that was the only one I did it to and marked it with green marker to see what it does.

Thanks again

Matt

[1Shirt]

:coffee:With the heavy boolits of say 350 and over, if you are staying within 1% your are doing fine. To me visual inspection for consistancy is very adequate unless you are a very serious bench rest shooter, or shooting BPCtg Sils etc. Within the 1% level, at those weights, think it would take a machine rest to tell the difference in accuracy.
Good luck.
1Shirt!:coffeecom

[sqlbullet]

I want to know where you are getting commercial jacketed bullets with only .25 grain variance. Match grade bullets I know are very consistent, but even then I will have one or two out of a hundred 168 grain bullets that are over .5 grain one way or the other. In standard 150 grain bullets they will vary ±1.5 grains in extreme spread.

With the 200 grain bullets I cast for my 30-06, I sort them. From a given casting session 90% will be within a ±.5 spread. The rest I put back in the pot for the next casting session. Typically the extreme spread for the 10% that go back in is ±2 grains.

As others have said, if you extreme spread is less than 1%, you are doing well.

[mattbowen]

1Shirt;
I use to shoot BR with 308, the 45-70 will only be used for hunting and as long as I can hit a 2" cycle at 100 with open sights I feel comfortable I was just a little worried with a grain spread of 4gr that I was doing something wrong.
Sqlbullet;
I use Sierra 168gr HPBT match, when I was shooting competition in my last department I would weigh each bullet and each case and like you said I would find 1 to 3 boolits that were about .5 + or - and I would take those and put them in a different pile and shoot them later, all the rounds that were within .25 to .27 are the ones that I would use. When I hunt I use Sierra 165gr SPBT and I don't bother to weigh them as long as I get 1 moa at 110 yrds I am satisfied. I was just worried that I was doing something wrong, these were the first batch that I ever casted.

Thanks for your replies

Matt

[watkibe]

My calculator tells me that you have 0.8% extreme spread, so actually you are casting bullets that weigh almost exactly the same.
I got a new mold recently that is supposed to throw a 158 gr boolit, but they actually weigh 165 gr, which is a 4.4% discrepancy. I'm glad I notice it before I decided on a powder charge.
That's twice the number of grains your boolits vary by; in your case the difference is insignificant, whereas in my case it might be significant.

Sometimes percentages are very useful for assesing the accuracy and precision of a process.

[mattbowen]

Watkibe;

I am glad you caught it, that could have been a problem.

Thanks

Matt

[Bret4207]

If you're going for heavy loads it's always a good idea to weight a few samples. My RCBS 30-180FN weighs over 190 gs in my alloy, my 311316 (listed as 115 gr) weighs in over 120, my BD45 230gr FN weighs in closer to 242. OTH, I have a custom 6.5x150 gr that comes in near 140 grns! Same with a Lee 358-158 mould that comes in near 145.

Between manufacturing variations and alloy variations it's normal to have a fairly wide range of results in actual castings.