I read COWW will cast smaller and heaver then other alloys. What can be added to the WW metal to offset the shrinkage and the weight gain?
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I read COWW will cast smaller and heaver then other alloys. What can be added to the WW metal to offset the shrinkage and the weight gain?
Tin. The more lead in the alloy the smaller and heavier it will cast. There are some other methods of casting that exacerbate this, things like water dropping, etc.
Pure lead is the heaviest; more antimony or tin content makes the alloy lighter and also reduces shrinkage (at least with antimony; I have zero experience with lead/tin binary alloys).
I believe COWW is around 3% Sb, with a small amount of tin and a trace of arsenic. Typemetal or Rotometals SuperHard both have much more Sb, and mixed with COWW should make a lighter, harder boolit with less shrinkage.
IIRC, many if not most molds are cut assuming a certain alloy composition. At least one custom mold maker (Accurate) asks that you specify the alloy when ordering. Supposedly Lee molds drop at the specified diameter, but I don't know what alloy they assume will be used.
The common molds, Lyman, RCBS, etc. are made to cast what they are listed as with the Lyman #2 alloy.
More Lead, or a softer alloy will make them heavier.
For example: I cast what is listed as a .45 cal. 405 grain for my .45-70.
I make mine with much less Tin than #2, and they come out at around 422-424 grains.
Thanks for the replies.
I'm using a Lee 356-125 and didn't want the bullets any smaller then .356. Actually I would prefer them larger.
Powder coating can get your bullets a bit fatter.
I will be powder coating.
That PC will add at least a couple thousandths. It will also let you use a little softer casting alloy for better obturation.
Most molds are made with a given alloy in mind, like Lyman #2. So more lead, heavier & smaller, more tin, lighter & larger. Its really over thinking it imo. Just cast what you have. If PC & sizing, your final dia will always be the same & small weight diff between alloys means nothing when talking handgun bullets.
Alloy temperature can play a part in the final size of boolits. The hotter you cast, the smaller the boolits. When an alloy is heated it expands like most things. When it cools after being poured into the mold it shrinks.
Once again thanks for the help.
I have lead, lino, tin, and of course the wheel weights. I just didn't know how the addition of the different metals would effect the outcome.
I think I will try the addition of tin first. I sounds like what I'm after.
Any suggestions for percentages of tin for 10# of wheel weights?
1% is all you need for nice casting. Anything else is just wasting tin. When I make LHP I use 25-1 or 20-1 depending on the HP design. Though for general shooting of solids, I just cast range scrap or clip ww cut with pure. You dont need hard bullets for most applications. I really dont care about final weight either. IF the mold says 124 & they come out 128, dont care.Quote:
Originally Posted by MR CHEN
Take the COWW and mix 50-50 with soft scrap lead , add 1% linotype for added tin to help castibility (fill out) if you have it . The boolits from this mix drop from Lee #356-120-TC ( double cavity ) right at .357" ... I run them through a .357" lube/sizer die to round them out ... powder coating should get you the size you want . I confess to not weighing one ... I use 120 - 124 grain load data and don't exceed max charges . Agonizing over exact weights is a waste of time ... every time the boolit metal mix changes the weight may vary slightly...slight variations are not worth trying to correct ...Quote:
Originally Posted by MR CHEN
Trying to correct for a slight weight gain will drive you crazy so don't worry about that .
I'm not sure what alloy Lee uses to set their mould weights ...Lyman uses Lyman #2 and NOE uses COWW . Try not to let all the variances get to you ... this stuff isn't an exact science .
Do the best you can with what you got !
Gary
Thank you fredj338 and gwpercle.
I wanted to target the published weight of the mold. I have cast 20# of CLOWW/w 2% tin with the Lee 356-125 and I'm seeing what you have described........ You get what you get, run with that.
just do it, get good molds, lots of clip on wheel weights, add a little tin and cast away. don't get too hung up on exacting weights as long as you get consistancy of good mold fill out and you work your loads up. size .002 over or as big as you can so loads still chamber. use good proven lube or as others say powder coating will be better than traditional lube sizing. this is just my opinion as a non expert but this formula for casting has been loading most of my guns for quite some time now with zero problems
Thank You farmbifQuote:
Originally Posted by farmbif
This is just what I have done. COWW + 2% tin. They fill the mold just great and are coming out a little heaver and a little bigger, but I see now that, that's all good. I was having good success running the melt at 695* according to the PID.
The wheel weights I have are form the 70s. I'm not sure of their exact composition but they make nice bullets.
Is there a large range of hardness for COWW, I think some of mine are much softer than others.
I have the same issue my bullets come out 150gr instead of 147.