OT cast bullet weight question

[Bis]

Being new to casting bullets, I am a little confused. I am using a Lee 2 cavity mold for 45/70 405 grain RFP and straight wheel weights. The problem is that the weight of the bullets is all over the place or at least it seems to me. I cast 92 bullets and the weight ranges from 400.0 grains to 408.3 grains, the diameter of all the bullets seems to be the same. The majority of the bullets (64) fall on a range of 404.0-407.9.

Why is there such a difference in weight, all bullets came from the same batch of wheel weights?

Will 8.3 grains difference in weight between heaviest and lightest make that much difference. I will be using them mostly for target shooting off my back porch.

What is the normal tolerance for bullet weight? I know 0 would be great in a perfect world.

Thanks for your help.

Ken

[flatnose]

Mold temp not stable, or pot temp changing. Make sure lead is clean and well fluxed. A 5grn variance on a 405grn bullet wont make a lot of difference to accuracy.
Weight sort your bullets if you want better tolerances.

[Don McDowell]

Lots of things could be affecting that.
Wheelweight alloy might not be blended real good so there's pockets of lighter and heavier metal. Flux and stir quite often.
How tight you squeeze the handles will change.
How well the mold fills out will make weight differences.
How you pour will make a difference, bottom pouring out of the pot will give you wide variations especially with bullets over 300 grs. Ladle pouring with a lyman or rcbs ladle will make for tighter weight variances.

Once you get everything down you probably will notice a 1gr variation or less. And rejects will be well under 10%.

[Bis]

Thanks for the reply.

I am using a bottom pour pot Left over from my muzzel loading days 30 years ago.

Does 8 grain difference in weight make that much difference down range?

[TedH]

You could also have some air pockets in the really light ones. Try different techniques when pouring like holding the mold as an angle so the alloy kind of swirls around in the mold as it fills. Don't be afraid to leave a large spru on top either.

I'm kind of anal about my cast bullets, so I weigh them on a digital scale. With big bullets like the 45-70s any that are over +/- 2 grains get tossed back in the pot. 200 gr. and under bullets I like to keep them +/- one grain. Probably just makes more work for myself, but that's how I do it. Once you get a good technique going there will not be many that get rejected.

[shooter]

Thanks for the reply.

I am using a bottom pour pot Left over from my muzzel loading days 30 years ago.

Does 8 grain difference in weight make that much difference down range?

If you're shooting paper you may not shoot as tight a groups as you would like. A deer probably won't notice the difference, though. I think for all practical field purposes it will be fine. If you want more accurate loads for hunting, weight sort the bullets so you will have more consistent results, and make a bunch for just hunting and use the rest for plinking. Just depends on what you're looking to do as to whether it will make a big difference down range.

[Chuck 100 yd]

You must use a good pace when casting with an aluminum mold like the Lee. They are not large and they expand and contract a lot with heat changes. And the alloy temp must stay close to the same during the casting session also or bullet weights all over the place will result.

As said,just sort them into batches of like weights and go have fun!!

[Don McDowell]

Bis 2 or 3 grs won't make all that much difference. 8 grs tho is something altoghether different. As an example if your pushing the envelope with reloads, that 8gr heavy bullet may put your load over the top pressure wise.

[Bis]

I guess I need to be more consistant with my casting. When I did the 45/70's I was trying to get more 44 mag bullets. So Some times I would cast 1 set of 44's and 1 set of 45/70's the next time I would cast 3 sets of 44's and 1 set of 45/70's. I had the same problem with bullet weight with the 44 mag bullets.

[Old Savage]

Ah, grasshopper, there is much to learn here. And, only experience can teach some of it but, these advanced casting guys can be a good guide.

[Don McDowell]

Biz if I'm casting more than one mould at a time, I cast the smallest to the largest. Fill the smallest set it down, fill the biggest, cut the sprue and refill the smallest, cut the sprue and refill the biggest, so on and so forth.
The trick is to keep an even motion so the molds stay fairly close to the same heat level.

[Bis]

I see the value of casting one size then the other, but what do you do when you have to add more material to the pot? The temp of the material will be lower for awhile won't it?

[2X22]

Consistancy is EVERYTHING. I tend to only cast with one mould at a time and keep bullets only after perfect ones are coming. Then I flux one last time and don't flux again until I'm done. Don't add metal as the level goes down. Cast until you are have enough or your pot is very very low and the bullets aren't filling out. Then work through the progression again. You have to keep everything consistant.

If you are using straight WW's, even a 1/2lb of tin for a 20lb pot will make a great difference in how well your bullet cast and fill out.

Even at 420grs I rarely have more than a 1gr difference in bullets. I rarely weigh unless out of curiousity. My bullets are very consistant.

Did I mention consistancy?

2x22

[HEAD0001]

I do a couple of thing to get consistent bullets.

The first is use a good thermometer. Maintain a constant temp. of your alloy. When you add ingots allow them to come to temp. Flux well. I mix my ingots twice to maintain a constant alloy.

Use a ladle. I get better bullets from a ladle instead of a bottom pour.

Develop a cadence. Start counting when you cast your bullets and strive to do each procedure at the correct cadence. It will become second nature after a while. The cadence is the most important part to consistent bullets. Try dipping at 1. Lining you ladle up at 3. Pour your lead at the same number as well. Your bullets will greatly benefit.

And this last one you might not like but here goes. Sell those Lee molds to someone else and buy RCBS molds. Your consistency will improve drastically. Tom.

[Glenn]

Bis,
An 8 grain spread when the bullets mic the same diameter is caused by air bubbles in the bullets. These are caused by the way the lead is poured in the mould. A bottom pour pot is the most difficult with which to cast high quality bullets. If you have an RCBS or Lyman dipper, that's the easiest way to cast quality bullets. Lacking either, keep the spout open for a good second or two after the mould cavity is full. Yes, this can make a mess! Have your ingot mould under the spout to catch the run-off. This keeps the lead in the cavity molten long enough for the air bubbles to work their way up and out. Ed Wosika turned me on to this trick. He calls it the "standing wave" method. Sometimes you can see a little wave of the metal coming out of the cavity when you're pouring the "extra" in. Using either the dipper or this method you should be able to cast about 90% of your 400 gr. bullets in a +/- 1 gr. spread.
Add the sprues and run-off back to the pot each pour. This way you can go longer before you have to add ingots and wait for the lead to come back up to temp. Don't worry about the constituents separating out. It's called an alloy because they are fully alloyed, all the time. I know this doesn’t make sense, but that's what the metallurgists tell us, and they got all that high dollar schoolin' behind 'em. Just flux when you need to remove dirt and dross.
I'll crawl back under my rock now...
Glenn

[2X22]

Sell those Lee molds to someone else and buy RCBS molds. Your consistency will improve drastically.

YES!

2x22

[Bis]

Thanks for all the info. I need to go try this again as soon as I get another day off.

Which one of you guys was going to loan me the money to get those RCBS molds

[jlchucker]

I cast for nearly every rifle I own. What the other guys have been saying is worth paying attention to. It does take practice, but in the end, you'll get it, and the result will be bullets (or "boolets" as they say on the Cast Boolets website) that will shoot every bit as good as the jacketed ones. Some even better! The Cast Boolets website is a good one if you really want to get into casting. Those guys (some of whom probably post on this site as well) have casting experience with everything imaginable. They've used every kind of trick in the book--some even WROTE the books. They've hunted everything from field mice to elephants with cast bullets. They thrive on sharing information on what used to be a lost, but necessary art. Good luck, and don't give up. Casting's worth it, and a lot of fun. As a cautionary note though--SAFETY is the most important part. ALWAYS PAY CLOSE ATTENTION TO WHAT YOU ARE DOING, AND WHERE EVERYTHING IS ON YOUR BENCH. If you already don't have one, get one of those clear plastic face shields, just in case something spatters, and wear gloves.

[Bis]

Thanks jlchucker. When I cast I wear a heavy jacket, gloves and a face mask. I look like the kid on "a Christmas Story". I will have to check out the cast boolets site.