Advice on Lyman molds

[Ateam]

So my wife bought me a .452 devastator mold from lyman for my birthday. It is maybe my 7th mold, and I cast a fair amount, but I just could not get it to cast to an acceptable size, so I returned it to midway for another (midway is excellent like that). I just got back from vacation, and found my new mold in my accumulated mail. I fired up the pot and got to work with the new mold, and wouldn't you know it, 3+ thou under sized. So I am at my whits end here, let me know if anything I am doing stands out as wrong, and resulting in small boolits. Am open to all suggestions, but am seriously about to write off lyman molds for good.
-I cast almost exclusively with COWW with a little tin when necessary
-I ran the pot temp all the way up to 800 or so
-mold temp was kept just under frosty

I guess I expect a mold to cast at least at bore diameter, or better yet 2-3 thou over. Is this too much to ask? Are my expectations out of line? Any suggestions of molds that would fit the bill?

[pworley1]

Are you saying that it casts .449?

[Mal Paso]

He's only got 454 but this mold comes up fairly often in group buys in 452, 2 and 4 cavity and maybe optional gas checks. https://www.mp-molds.com/e-shop/mold...40-hp-pb-2-cav

I have had the 44 cal mold and it makes hollow points fun.

I went round with Lyman molds and moved on. I lapped a 4 cavity but it's a full days work.

[c1skout]

I've got that mold and it casts right at or slightly above .452 with coww. I do have to run it hot to make the hollow point work.

[mehavey]

Get the temp down to 700 or so.

[Ateam]

Are you saying that it casts .449?

Yes, 449-450. Is gets up to 452, but along the parting seam and I know is not a true dimension. These measurements are almost identical to the first mold.

[blue32]

I did the Lyman dance for a while then moved on.

[dimaprok]

So my wife bought me a .452 devastator mold from lyman for my birthday. It is maybe my 7th mold, and I cast a fair amount, but I just could not get it to cast to an acceptable size, so I returned it to midway for another (midway is excellent like that). I just got back from vacation, and found my new mold in my accumulated mail. I fired up the pot and got to work with the new mold, and wouldn't you know it, 3+ thou under sized. So I am at my whits end here, let me know if anything I am doing stands out as wrong, and resulting in small boolits. Am open to all suggestions, but am seriously about to write off lyman molds for good.
-I cast almost exclusively with COWW with a little tin when necessary
-I ran the pot temp all the way up to 800 or so
-mold temp was kept just under frosty

I guess I expect a mold to cast at least at bore diameter, or better yet 2-3 thou over. Is this too much to ask? Are my expectations out of line? Any suggestions of molds that would fit the bill?

I ordered my 1st Lyman mold from midwayusa because it was on sale in 22 cal and it had one cavity in the nose with a groove like a chip that got welded to the cutter and scratched out a groove, pretty obvious with a naked eye. I decided to cast anyway and it was undersized also the mold is 225 but i was getting 223 or slightly less. Returned it.

Sent from my SM-G950U1 using Tapatalk

[HangFireW8]

With more mold preheat, pressure casting with a ladle, and linotype or original Lyman#2, you MIGHT get the mold to case to exactly bore diameter. That is how Lyman makes molds now, and they see NO problem with it.

I did this dance with a new 311041. I expected .311. I got under .308. I sent it back to Lyman and they saw no problem with it. They said they lapped it but I still got only .308 at best.

Now I buy Mihec and NOE.

[kungfustyle]

Try using the Lyman #2 mix that's what the mold is made for aka 90% Lead 5% antimony and 5% tin. NOE molds are made for clip on wheel weights like you are using, but Lyman's are designed around the #2. If you have some lino type use some of it say 2 coww per 1 lino and add 1 lb of 60/40 solder that should be very close to #2

[porthos]

the only good molds that lyman made are probably 40 years old or older. after that; its a crapshoot.

[lavenatti]

I may make fun of Lee molds on occasion but I've never had to return one. My NOE molds are beauties.

Lyman molds have all gone back, all undersized. Like plenty of previous threads have said, I've moved on.

[RobS]

You can mess around with adding more tin in the alloy or adjusting it to #2 alloy or similar as been suggested to help with fill out which may give you what you are after. I stopped working with Lyman molds long ago due to better options.

At the cost of a new Lyman mold these days for just a touch more there are other options.

https://www.mp-molds.com/e-shop/mold...2-200-hp-2-cav
https://www.mp-molds.com/e-shop/mold...2-200-hp-4-cav

or my favorite 45 acp hollow point mold

https://www.mp-molds.com/e-shop/mold...cav-brass-mold

[WHITETAIL]

I have not bought a Lyman mold in about 20+ years.
Not when you have a multitude of other molds.
The last 2 I got were NOE and never looked back.

[country gent]

You can try adjusting alloy to get the bigger bullet, but then its always that alloy to get the results and you still have the out of round to deal with. Lapping the mould to cast to size with your alloy is doable and gives the benefit of a rounder bullet when done. On a single cavity mould lapping isn't as big a job as multiple cavities are. But it is time and labor intensive. Also you want to have the pot hot when lapping to check size occasionally as you lapp it out.

To lapp a mould you need the following tools / materials. A tee type tap handle, lapping compound in 320, 480, and 600 grits. Tooth paste simichrome or flitz metal polish.A length of 1/8" key stock.

Cut several lengths of key stock long enough to protrude out of the blocks for the tap handle to hold on. Some clearance between blocks and handle is good.

cast several decent bullets with mould

Drill hollow points out to where the 1/8 key just slips into hole and glue in. epoxy is good but cure time is longer. Super glue gels work also.

You now have your lapps make 2-3 here

Impregnate the first lapp with 320 grit. a small amount of compound on a flat steel plate and roll the bullet lapp between it and a second plate with light force, this impregnates the compound into the lead.

Carefully insert into blocks and close them clamp lightly in a vise and work the lapp back and forth ( in a tapping motion) 3-4 times and rotate 1/4 turn thru 2-3 full revolutions. Repeat this with each grit. If you watch wile lapping you will see bright spots appear on the high points as you cut. After the pass with the 600 grit clean the mould and pre heat it and cast a few good bullets for size. Bullets should look very nice and drop from mould well due to truer surfaces better finish and the removal of fine burrs and rough edges.

If still under sized much repeat the above procedure, if a small amount impregnate with the final polish and finish the cavity to a fine finish and check again. When done bullets should be rund and to size.

[M-96 Hunter]

The simple fix for Lyman molds is to buy NOE molds.

[Ateam]

I may make up a batch of #2, though it seems a waste of precious tin, and who wants a hp that hard anyway? Oh well, back it goes. Those MP molds sure are pretty...

[mehavey]

Again... run that #2 at 700°

[Taterhead]

Could be a candidate for powder coating. Where possible, I'm likely to order my next molds a hair undersized so that I'm not sizing as much after powder coating.

[RobS]

MP molds are indeed worth the extra cost and truly a pleasure to use.

I may make up a batch of #2, though it seems a waste of precious tin, and who wants a hp that hard anyway? Oh well, back it goes. Those MP molds sure are pretty...