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| Lyman's molds are built for casting with no 2 lead.
I have had the same problem with using WW and range scrap.I had to add some tin in the range scrap to get it to fill.
Just play with your lead mix and temperature of the pot. |
| | | Posts: 1371 | Location: Plains,TEXAS | Registered: 14 January 2008 | 
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| If you look at the specs for Lyman moulds, you will find their tolerance is +/- 5%, if memory serves. That means that cavity to cavity there can be as much as a 10% deviation. That is 13 grains in a 130-grain mould! Their moulds are not typically that far off, but they can be.
I would suggest one of two options: either segregate bullets by weight, or try to find Hensley and Gibbs moulds that fit your application. They are incredibly close cavity to cavity.
best of luck,
Doubless |
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| Thanks that all sound good to me. I'll try seperating by weight and see how that goes. |
| | | Posts: 215 | Location: BRF mid west WI. | Registered: 28 February 2003 |
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| That's a big difference. If your mold isn't hot enough to begin with the first bullets will come out light because they they harden before they completely fill the mold.
I preheat my molds on a hot plate and get few rejects. Light bullets get thrown back because they may have voids in them that cause erratic trajectory. |
| | | Posts: 388 | Location: NW Oregon | Registered: 13 November 2005 |
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| You've gotten answers for 2 totally different issues. As I understand your question, SOME of your bullets are showing a 5-6 gn. variation. THAT is a problem with your metal possibly not being sufficiently clean, or your technique, temp, etc. NOT a problem with the mold. If you were getting good PRECISION...i.e. all bullets cast were the same wt....you would want to look at the composition of your alloy, or the mold itself. |
| | | Posts: 953 | Location: Florida | Registered: 17 March 2005 |
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| Okay, I assumed something, and Don is right. There are a lot of things that factor in to variances in bullet weights... For absolute consistency, pour with a ladle and use a single cavity mould. The results, once you get the technique down, will be amazing. But that method is very time consuming, and a lot of work.
If you buy a multi-cavity mould, expect some variation. Period. You can still ladle cast with a two-cavity, but it becomes trickier.
Enter the bottom pour pot: You will find that as the level in the pot drops, bullet weight variation will increase, because pressure of the pour is lowering. Speed goes up, multi-cavity moulds are more timely, but weight variation becomes a factor.
I have found huge variations in commercially cast projectiles. I attribute that to the fact that most commercial casting machines use eight two-cavity moulds. That allows for potentially 16 different weights of bullet in a single box.
The absolute best answer, as I said earlier, is a single cavity mould and ladle casting, especially for rifles. Handguns are more forgiving, but even they are helped by keeping variation to a minimum.
Determine what you are willing to accept in weight variation and go from there. The rest is good quality alloy, equipment, and technique.
Good luck! |
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| I'm rather new to casting as well and have a .416 RCBS mould.
After visual inspection I am left with about 20-25% of what I have cast. I then weigh them on a jewellers scale and accept only two weights. 357 and 358 grains. The rest go back in the pot.
This is a very small variation but I figure the less variables the better. |
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| quote: Originally posted by Doubless:
Okay, I assumed something, and Don is right. There are a lot of things that factor in to variances in bullet weights... For absolute consistency, pour with a ladle and use a single cavity mould. The results, once you get the technique down, will be amazing. But that method is very time consuming, and a lot of work.
If you buy a multi-cavity mould, expect some variation. Period. You can still ladle cast with a two-cavity, but it becomes trickier.
Enter the bottom pour pot: You will find that as the level in the pot drops, bullet weight variation will increase, because pressure of the pour is lowering. Speed goes up, multi-cavity moulds are more timely, but weight variation becomes a factor.
I have found huge variations in commercially cast projectiles. I attribute that to the fact that most commercial casting machines use eight two-cavity moulds. That allows for potentially 16 different weights of bullet in a single box.
The absolute best answer, as I said earlier, is a single cavity mould and ladle casting, especially for rifles. Handguns are more forgiving, but even they are helped by keeping variation to a minimum.
Determine what you are willing to accept in weight variation and go from there. The rest is good quality alloy, equipment, and technique.
Good luck!
So much crap about bottom pours. Especially the one about the as the pot level goes down so does the pressure of the pour stream. Well guess what? Good bottom pours, like the RCBS, have an adjustment screw on the valve to increase the flow up or down. One isn't supposed to put the sprue right up against the pot spout so it's more a time factor then a pressure one. I'll admit the cheapo bottom pours may have the problem mentioned, but not the better ones. I cast some pretty darn good bullets with my RCBS including minimum weight variation and good fill out. Don Edwards nailed the problem on the head. |
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| Iseem to have two weights. I centered my RCBS 505 scale for 132gr. the lighter weight of the two groups. That group is pretty close maybe a tenth or so either way. The other group is at the top of the balance beam but not touching the stop. This bullet seems pretty consistant also. I ladle pour my bullets. Wheel weights with a little more tin added. So I think I will weigh each one get my two groups and see how they shoot. Than maybe I'll just us one cavity next time I pour. Thank for all your help. |
| | | Posts: 215 | Location: BRF mid west WI. | Registered: 28 February 2003 |
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| quote: Originally posted by 257 Rock:
Iseem to have two weights. I centered my RCBS 505 scale for 132gr. the lighter weight of the two groups. That group is pretty close maybe a tenth or so either way. The other group is at the top of the balance beam but not touching the stop. This bullet seems pretty consistant also. I ladle pour my bullets. Wheel weights with a little more tin added. So I think I will weigh each one get my two groups and see how they shoot. Than maybe I'll just us one cavity next time I pour. Thank for all your help.
5-6 grains difference in a 130 grain bullet, I didn't think even Lyman could F up a mold that bad! I would do as recommended and cast a large lot from a single cavity of this mold, in other words make sure it is a mold problem and not you or the alloy, sounds kinda far fetched at that much difference. Now as to the bottom pour VS the ladle, it's your choice, I started BP now ladle, just my personel choice, both make good bullets. |
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| I agree with swheeler. Cast a bunch of one cavity, or mark the other cavity so you can identify that cavity and cast from both and sort them out. Once you find a good load with one cavity the other will more then likely do okay too, but not shooting both together in mixed loads.
You need to get your melt and mold up to the correct operating temperature and then keep a steady pace and rhythm and you should cast consistent weight and good bullets. |
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| 24k pot or cheapest chinese model or ladle--doesn't matter--you have a stream of molten lead entering your mold. If you have weight differences it's in the cavities of the mold. I started out with ladle and once I started bottom pour, I'd never go back to ladle. |
| | | Posts: 3811 | Location: san angelo tx | Registered: 18 November 2009 |
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| Well I cast up some bullets using just the front of the mould. After I weighed them up I was only off about 2 tenths for about thirty that I kept this time. So that looks pretty good. I weighed some that I had cast before and found that there is two groups that are 4.5 grains apart. So I think I will just cast from the front of the mould.
I do have about 100 loaded from the first pour so I'll shoot them against the second batch and see what the groups look like. Thanks for all the help it sure cuts down on the learning curve. [I hope] Tony |
| | | Posts: 215 | Location: BRF mid west WI. | Registered: 28 February 2003 |
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