Lyman 429421 Bullet Mold

[robertbank]

It must be my week for poor luck. I don't cast this bullet often and use it less. I had a coffee can full of these bullets cast some time ago. I decided to load some up for my rifle. For a reason only bullet God knows I decided to check a few of them with my micrometer and I find I have a pile of bullets coming out of my mold at .425 which is a distance away from .429. I use WW alloy. Do I have a bum mold or is there something I can do alloy wise to get a larger bullet from my mold. I would have though the bullets would be dropping around .430 - .431 for sizing down to .421.

Take Care

Bob

[Nueces]

The best you could do (linotype) for a diameter increase would be no more than about 0.001" for that size.

You could consider marketing it as a rare, nearly unobtainable Lyman Keith design for the old small bore 44-40s. Who knows, you may get a bite!

I assume, of course, that your can of slugs was as cast and not sized and forgotten.

[Mal Paso]

You likely want to cast .431" or better to size .430" for a .429 groove.

More recent Lyman are often too small.

You can "beagle" the mold using aluminum hvac tape on the mold face. I lapped one larger with diamond grit rolled onto the bands of a bullet cast from the mold and spun in the cavities with a drill.

Lyman is a great casting mold but often the holes aren't right. If it's too much trouble to fix Arsenal Molds will cut an aluminum one just for you for less than a hundred.

[JonB_in_Glencoe]

That is crazy small.

If this were happening to me, I'd do two things.

First, I'd cast some fresh boolits from that mold, keep mold temp as cool as possible, meaning cast shiney boolits, not frosty boolits.

Second, check/calibrate the Micrometer.

If your results are that same after that, then I imagine you have a "bum mold" as you suggest.

[bmortell]

id do 2 wraps tracing paper with the front rolled over the front band, dry, wipe some sort of lube on lightly, size as normal, load with straight crimp.

[robertbank]

Thanks guys. I will scout a replacement.

I should send the mold back to Lyman and tell them they put the wrong mold number on this one. It should read 425421. :>)

Take Care

Bob

[kungfustyle]

Try to get a little closer to lyman #2 if you can add some linotype to get it to 90/5/5 should put you right at .430 or .431. If you powder coat you can get those to .432 or so. But defiantly cast again before you discount the mold. You can just cast a few with it on your next casting session to be sure.

[robertbank]

I will give it another try. I don't have any Lino. I will also powder coat them. It might be the answer.

Take Care

Bob

[sw282]

l have found l can vary the size of my boolits quite a bit w PC HF RED. Each coat is about .0015'', with a couple coats@ .003''. For ME the Lee push thru sizer die does a better job than a RCBS Lub a matic...

[Ozark mike]

If my molds cast small I use valve grinding compound and run a wood screw into a fresh boolit and spin er away until I reach .001 over chamber dia

[Larry Gibson]

Your Lyman mould is cut for a "hard" alloy either #2 or linotype. The nominal diameter is .429. Using one of those alloys should get you bullets of .429 - .430. Undersize bullets from newer Lyman and RCBS moulds is a common problem when plain COWWs are used, especially if much of the SOWWs are in the mix also.

Besides a correct alloy a correct casting technique is also needed. Not saying you don't know how to cast bullets but just a reminder on how to get correctly sized bullets out of Lyman and RCBS moulds. If using a dipper then the technique shown in earlier than the CBH #4 works very well. Hold the mold over the pot when pouring and pour a generous sprue letting the run off go back into the pot.

With a bottom pour keep the sprue plate about 1/2" from the spout. Again fill each cavity separately allowing a generous sprue to form before moving to the next cavity. The hot alloy should "boil" up out of the cavity when it is properly filled. Open the flow up so the alloy gets into the cavity as quickly as possible.

The alloy should be at 710 to 725 degrees for best casting with ternary alloys (that includes COWW alloy). A lessor alloy temperature, especially if casting in a cold area such as in a garage or outside in the winter, will cause the alloy to solidify faster resulting in smaller diameter bullets.

I've had many Lyman moulds sent to me to test that supposedly would not cast to nominal diameter. Using Lyman #2 alloy they all have cast .001+ over nominal diameter. Even COWWs + 2% tin they all cast to nominal diameter.

If you are dead set on using just WWs as an alloy then I suggest an NOE mould as most are specified and cut for COWW alloy.

BTW; Over the years I shot thousands of 429421 cast of COWWs (granted the older ones with more tin in them) sized .429 out of several 44 Magnums and 44 SPLs with excellent accuracy and no leading out of several revolvers and a couple rifles. I currently size several different 44 cast bullets at .430 for all but my Colt Anaconda and Ruger OM Vaquero 44-40 which need .429 sized bullets to fit the throats. I know it is heresy to say sizing other than to "fit the throats is a must for best accuracy" but I've found that is not always the case. My testing of several different .44 cast bullets has shown no difference in accuracy between a cast bullet sized .430, .431 and .432 in cylinder throats of .431 - .4315 (pin gauged). I also found any bullet sized over .002 - .003" over barrel groove diameter was actually less accurate than a bullet sized to groove diameter. As to leading I found many years ago leading is more a function of alloy composition and the lube used, mostly the lube used. In my magnum handgun loads with PB'd cast bullets I most often use COWWs +2% tin or a 94/3/3 alloy which is similar and both having a 12 - 16 BHN when AC'd. For low end or medium level handgun loads (up through 1100 fps) with PB cast bullets a bit softer alloy is used (BHN 9 - 11). I prefer a good soft lube such as NRA 50/50 or BAC.

[robertbank]

Thanks Larry. I am using WW with a touch of 50/50 solder for mold fill out. I have some hard lead shot I could add for additional antimony but I am not sure I would be gaining anything in hardness. I cast as hot as my RCBS pot will produce. As to the technique I mimic your method. I only use a dipper when casting hollow base bullets or hollow point bullets. I find the bottom pour method to be faster when casting 4 cavity molds. I do pour a generous sprue.

Finding lino up here is more than a bit of a problem. Given I don't spend a lot of time with the .44mag it may be less expensive to just invest in another larger mold than to chase down a source of harder lead. I have lots of time to play with this so I'll devote a couple of rainy days to this project and report back here as to my progress. I may just have to let the Queen breath a bit and convert some of my Cdn$ to Yankee coin and purchase another mold.

A huge thank you to all who have replied and to who have yet to.

Take Care

Bob

[Bigslug]

Are you measuring the front driving band, or the base?

Elmer Keith's formula ended with three equal length, full-diameter driving bands, with a large capacity, square-bottomed lube groove. His falling out with Lyman was due to their tendency to change any of those features with zero notice given to those who might be buying their molds. I have a 358429 with a front driving band significantly narrower than the rest. As I recall, the base is too narrow as well (not using it anymore) - but my point is, measure the whole slug.