Undersize moulds???

[andym79]

Hi guys, I have a few moulds. I have noticed that my moulds from NOE Accurate and CBE all cast to the diameter that they claim to be, some a little over (but over isn't a problem). The Lyman and RCBS moulds I have either cast to size or under!

I have one 25 calibre mould for my 25-35 an RCBS, a guy from my range sold it to me said it was a good bullet. I went home casted about 100 sweet looking bullets. The next day I go to size them in the lube-a-matic and they are falling in to the sizing die!

It would be a good bullet, if it sized .003 larger, they come out at .255 and I am not using Linotype just because the cherry must have been worn at the RCBS factory. I asked him about it, he said he had a 25-35 and it shot terrible so he sold it. Well mine groups 8" at 50 yards with this mould, but two bullets can touch and three stay in an 1 1/2" if I do my part at 100 yards with my NOE moulds!

Did he deliberately sell me a lemon? Or did he not consider why his 25-35 did not shoot too well? I guess all of this is sort of irrelevant!

Is there anything I can do to open it up .003"?

Or is this mould good for a rusty ornament or scrap metal.

Needless to say I have taken a vow to myself that I will not be buying anymore Lyman or RCBS moulds, I have a couple of Lees they cast to size and for the price they are not too much of a gamble. No its the independents for me from now on, that way I know my $80-100 is buying something more useful than an ugly ornament!

Sorry for the rant, but I thought machine tooling kinda got perfected nearly 150 years ago in New England!

[high standard 40]

I have two RCBS molds that had a similar problem but not quite that bad. There is a way to get that mold .003" bigger but you will have to invest a little more to achieve that goal. In my instance, my 7MM 145 SIL mold delivered a bullet measuring .285" and while this is to spec, it would not fill my generous chamber. I needed at least .287". In my situation, this bullet design was exactly what I wanted, just needed it to have larger diameter drive bands. Nobody else, not even the custom mold companies, had what I needed. So I sent my mold to Erik at Hollow Point Molds and he machined my mold to deliver just what I needed. His service is not free but he was able to deliver exactly what I wanted for my 7mm mold and then later a 22 cal mold that had the same issue. Link below if you decide to go this route.

http://www.hollowpointmold.com/#insetbar

[Shiloh]

The worst of my lot are the Lyman 311041 and the 311299. NONE of the LEE 9mm molds I have drop large enough to use.

SHiloh

[andym79]

Just confirming what I have suspected for a while the majors are not really providing what we want/need.

I have both those moulds but NOE versions and they being larger in diameter are fine.

[tazman]

I have had the same issues with a variety of molds from major manufacturers(Lee, Lyman, RCBS, saeco) across a number of cartridges. It can be a bit of a **** shoot as to whether the boolit will be large enough to work properly in your individual gun.
I have several NOE molds and all of them have been large enough to work properly as in dropping boolits the size they advertise. I don't have experience with other brands of premium molds.
When you get a good, properly sized mold from a major manufacturer, they work really well.
Often the premium mold makers don't have a specific design in their catalogue so you have no choice as to which mold to buy.

[Wayne Smith]

I have had the same issues with a variety of molds from major manufacturers(Lee, Lyman, RCBS, saeco) across a number of cartridges. It can be a bit of a **** shoot as to whether the boolit will be large enough to work properly in your individual gun.
When you get a good, properly sized mold from a major manufacturer, they work really well.
Often the premium mold makers don't have a specific design in their catalogue so you have no choice as to which mold to buy.

Your choice is to go over to www.mountainmolds.com and design your own and Dan will cut it to your specs. He will advise design on his site too.

[tazman]

I have heard that. I just haven't done it yet because I have all the molds I need at the moment. That may change with the purchase of another gun and cartridge, so I will keep it in mind.

[Larry Gibson]

Bet you all are using WWs......thats why the NOE moulds drop at nominal diameter with COWWs.....because that's what they are cut for. RCBS moulds are mostly cut for linotype. Lyman moulds are mostly now cut for #2 alloy. Use the right alloy and correct casting technique and you'll get a correct diameter for the mould. Don't expect RCBS or newer Lyman moulds to cast 2 -3 thousanths over nominal diameter because they won't. Do expect 2 - 3 thousanths over if you use #2 alloy or linotype in a NOE mould.

The RCBS and Lyman moulds may be "undersize" for what you want with the alloy you're using and perhaps with the casting method used. However, with the alloy they are cut for and a proper casting technique they will, most likely, cast to their nominal diameter.

Not saying you guys don't know how to cast, just saying you're using the wrong tools for what you want done. If you want to cast with WWs then NOE moulds are also my 1st choice as they are the tool for that job.

Larry Gibson

[Maven]

Listen to Larry: He's spot on re: alloys used to determine Lyman, RCBS as cast mold diameters.

[NoAngel]

Depending on how much under they are you can always powder coat them up to size.

[FredBuddy]

Andym:

I expect Larry Gibson's advice is the "most correct."

I don't cast and shoot near as much as most here, and only use wheel weights. To bring my Lyman 292 gr. boolits up to size for my 45-70, I powder coat them. Works for me.

I've also been known to powdercoat 200 gr. SWC's that drop at .454 so I can use them in the 45-70. They work fine out to 40-50 yards or so.

I'm having a ton of fun shooting a wide range of cartridges at lower levels of recoil, and the personal satisfaction from putting them together is huge!

Thank you, all.

[high standard 40]

Bet you all are using WWs......thats why the NOE moulds drop at nominal diameter with COWWs.....because that's what they are cut for. RCBS moulds are mostly cut for linotype. Lyman moulds are mostly now cut for #2 alloy. Use the right alloy and correct casting technique and you'll get a correct diameter for the mould. Don't expect RCBS or newer Lyman moulds to cast 2 -3 thousanths over nominal diameter because they won't. Do expect 2 - 3 thousanths over if you use #2 alloy or linotype in a NOE mould.

The RCBS and Lyman moulds may be "undersize" for what you want with the alloy you're using and perhaps with the casting method used. However, with the alloy they are cut for and a proper casting technique they will, most likely, cast to their nominal diameter.

Not saying you guys don't know how to cast, just saying you're using the wrong tools for what you want done. If you want to cast with WWs then NOE moulds are also my 1st choice as they are the tool for that job.

Larry Gibson


I started with COWW + 2% but have long since settled on 92-6-2 foundry certified alloy. Both my RCBS molds still dropped bullets too small for my purpose. But in all fairness to Larry, my molds did drop bullets on factory spec......still just too small for what I needed. Also as Larry stated, technique has bearing here also. When everything failed for me, I had my molds modified. A custom mold wouldn't work for my 7MM because nobody would cut a mold with the nose profile that I wanted.

[tazman]

My alloy is range scrap sweetened with some linotype. Not as hard as No.2 but slightly harder than WW. It hardens nicely when water dropped. I have no idea of the actual content since it probably changes from batch to batch. It drops boolits from NOE molds right on the posted dimensions. An NOE .358-135-FN drops at 135 grains and .358 diameter.
I have one of the older(20 years or so) RCBS 38-180-sihouette molds that would not cast at .357 even with linotype regardless of temperature.
I still have it but don't use it since I loaned it to some one I thought was my friend and he ruined it by letting it rust badly.

[Oklahoma Rebel]

I think rcbs should change that, do they not realize how unrealistic it is to assume/expect everyone to be using friggin linotype? the should just do like noe, and cut for WW's, I do use lyman #2 pretty religiously, but I think lyman should cut theirs for WW's also, that's what everyone uses!

[country gent]

AndyM, you can adjust the "mould" to cast to the desired size with your alloy thru a process called lapping. cast several bullets with the mould. Clean mould good. Drill a small pin hole in the base as deep as possible with out breaking thru. 1/8" key stock makes a good stem. Epoxy a stem into the holes and let cure. These are now the lapps for working the cavity in the blocks. Lightly coat with 320-400 grit compound and seat the bullet into the cavity closing blocks around it . Once seated work the bullet with a tapping type motion back and forth 3-4 times 1/4-1/2 rotation. rotate 1/4 turn and repeat. repeat this thru 3 full rotations. Clean and cast some new slugs measuring to see where your at. and keep working to whereyouy want to be. Work down in grit to 600-800 grit for final finish.

[dmitch]

OR ..... have you considered 2 shims of tin foil to increase your boolit's dia. with this particular alloy. I had the same problem with a Lyman 457483 GC mold that I purchased from a member here. I wanted soft alloy for expansion so was getting an undersized boolit that the GC would not stay on. Two layers of tin foil carefully placed between the mold blocks now produces sizeable dimensions and a fine GC shank. Money saved for the next time it's time for another "Erik" project or to buy another mold.
dmitch

[Tackleberry41]

I could understand cutting a mold for linotype if it was sold for rifle, magnum handgun. But something like the Lyman 147gr 9mm, who would use lino? Any non gas checked bullet, should be cut for softer alloys. The lyman 147gr 9mm casts big enough, barely, if you can use .357 bullets. Any more and your a bit out of luck.

Lee must be cutting for lino, even the tumble lube ones where nobody is going to use lino. You have to sort of decide what your going to use a Lee for. Lino, use it as is. But Leementing to use a softer alloy and they cast way over size with lino. Its the alloy they use, as not seen it so much with my NOE molds.

[Toymaker]

Quick, Easy, Simple, Reversible - "Beagle" the mold. There are several threads that explain how and discuss results. My experience was fantastic.

[ghh3rd]

It's as frustrating as paying good money for a fine cigar, and not being able to draw smoke through it. I've had undersize molds, and feel your pain!

[fredj338]

Quick, Easy, Simple, Reversible - "Beagle" the mold. There are several threads that explain how and discuss results. My experience was fantastic.

This is what I have done to a couple of molds to get them 0.001" larger than final size. With PC though, I can almost get by w/o. You can also lap to a bit larger size using lapping compound but that isn't as easy.

[toallmy]

I will lap a mold in a heartbeat .

[big bore 99]

Ever try rolling a light knurl with a cross cut file on a wooden base? You can bump them up a couple thou easy that way, Or try beagleing as previous mentioned.