Why use fewer cavities per mold?

[Dahak]

I have a mix of 4, 6, and 8 cavity molds for handgun boolits and have not noticed a difference in quality between them after improving my temperature control and studying up on my alloys.

Looking at adding a new caliber, 30 carbine. I powder coat and use a ProMelt 2 (bottom pour pot). In looking at available molds, I'm having a hard time finding anything beyond 2 cavity.

I am assuming that 2 cavity is an artifact from when ladle pour pots dominated the market. Before I start researching what it would take to get a semi-custom 6 or 8 cavity mold made, I thought I would ask. Why use a mold with fewer cavities?

Update: after posting I saw this thread: https://castboolits.gunloads.com/sho...ld-is-adequate

My summary: Ladle pout is a reason to use fewer, hand/wrist issues is a reason to use fewer cavities. If those aren't in play, use as many as you want.

I'll leave this thread posted in case anyone wants to chime in here, but I think my inquiry here may be redundant.

[country gent]

Newer made moulds have fewer differences do to modern manufacturing and tooling. On older moulds fewer cavities meant less variation from each cavity were induced. Not as important on most handgun ammo but with rifles it would show.

In the past rifle bullets were cast in a single cavity mould or the cavities were identified and shot separately.

What I meant by modern manufacturing improvements is in the early 1900s +- .010 was tight production tolerances/ In the 1930s or so +- .005 was about the norm, In the 1960s or so it was +- .001-.002 now with modern cnc and other improvements its +- .0005 or better. This is on almost everything being made today. Our barrels dies moulds equipment are all much better than before

[Hick]

Maybe fewer cavities are an artifact of ladle pour-- but there are some of us who just like fewer cavities because it is easier (but not faster) to get more consistency. That is-- with two cavities there are fewer variables. I have a bottom pour pot (two actually) and all but two of my molds are two cavity. My only 4 cavity is for a pistol where variation between the cavities don't mean much. I only make and shoot around 10,000 rounds a year, so the slower work doesn't matter much anyway.

[poppy42]

I think it’s got more to do with the fact that you typically didn’t shoot as many rifle bullets as you do pistol bullets. I mean, I can go to the range and go through 300 9mm bullets in a heartbeat yet I wouldn’t shoot 300 bullets through my 30-06 at one sitting.

[poppy42]

As I sit here thinking about this, I don’t think it’s got anything to do with ladle pour versus bottom. I mean, I know plenty of guys that ladle poor 18 cavity buckshot molds and I’ve known a couple rifle casters that preferred to use ladle poor. I think it’s got more to do with the size of the bullet and the weight of the mold. hear me out cause I’m not talking about the actual weight of the bullet. I understand you can have heavier pistol bullets than you do rifle bullets, but let’s look at something like 158 grain wad cutter or semi wad cutter coming out of your 38 special or 357 magnum And then look at the length of 160 grain rifle bullet coming out of a 308 or 30-06. Longer bullet and longer the bullet the more mold you need the heavier mold gets. I understand there’s exceptions to rule but for the most part it’s got a lot to do with how much that mold is gonna weigh. I don’t know about anybody else, but I don’t know if I want to be casting a six cavity brass 350 grain mold for my 45/70. I mean it’s not like bottom pour pot is brand new. They’ve been around a long time and you typically get more cavitie pistol molds, then you rifle molds. I realize I could be completely wrong and out left field on this one, but that’s my story and I’m sticking to it lol

[walnut1704]

I use two cavities because of my hand, but also there's a lot of them available. I find them easier to get going and they meet my production needs. Of course I'm retired. Between late September and early April I cast over 8,000 pistol bullets using nothing but two cavity molds. I cast for about 5 hours at a time (two pot-fulls) once or twice a week as weather permitted. Each day produced roughly 1,000 bullets. A few more for 9mm, a few less for .41's. Did not seem onerous at all to me.

I think a second bottom-pour pot would speed me up more. But waiting on the second pot to heat gives me a break. In fact, if you're going for maximum production, it would seem to me that multi-cavity molds and two pots would go hand-in-hand. But I spent my entire working life optimizing production. I'm over it.

[Dahak]

My first rifle mold is a 6 cavity 230 grain 30 caliber used for subsonic 300 AAC, so my expectations are a little skewed. I'm trying to talk myself into a M1 carbine and if I can cast the bullets, I'm just in for primers and powder which helps in the self-persuasion.

[jsizemore]

I used a H&G #254 for years to shoot NRA hunter pistol silhouette in my 32-20 (actually 30-20). That mold was made for the M1 carbine but worked great for silhouette. About same case capacity as a 38 special but 10 twist barrel for decent stability out to 100 yards with lighter powder charges. The lighter weight bullet (110 gr if I remember correctly) in a 10 cavity mold meant you had to keep the casting pace up to maintain heat in the mold which made production great. Very consistent bullets too. I kept on using it even after the Hornet was approved for hunter pistol. It would hold minute of rams leg at 100 if I did my job. Now I'm over 70. I couldn't imagine going on a long casting run like I used to do in my 40's.

[dverna]

The only reasons to use fewer cavities with modern molds (see post 2 by country gent) is to save a few dollars, or someone who cannot handle a larger mold due to physical issues.

[Teddy (punchie)]

Cost and amount of shooting needs. I'm lucky to find time to sight (check) in the deer rifle let alone shoot enough to have to cast a 1000 bullet heads.

One deer Rifle I bet in 15 years I didn't have 50 to 60 round trough it and most of those were finding a load/powder to use. Shot a few deer with it around 20. So if it would be shooting cast why do you need a high production mold?

[dverna]

Cost and amount of shooting needs. I'm lucky to find time to sight (check) in the deer rifle let alone shoot enough to have to cast a 1000 bullet heads.

One deer Rifle I bet in 15 years I didn't have 50 to 60 round trough it and most of those were finding a load/powder to use. Shot a few deer with it around 20. So if it would be shooting cast why do you need a high production mold?

That is a good point. But....

Unless the rifle is some weird caliber, casting for a low volume caliber does not make much sense. If it will use less than 100 bullets in 10 years, buy a box of jacketed bullets and go hunt. In fact, it may not make sense to reload...never mind cast. BTW it is one reason why I do not use cast bullets in "real" rifles for serious work. I don't kill enough game to save any money, plus cast bullets do not have the accuracy or performance of jacketed bullets in the rifle calibers I shoot.

For most of us this is a hobby so we "waste" time and resources to have fun. In my case, I do not need a 1 MOA deer rifle, but I took the time to work up a load. OTOH, I Have shot upwards of 5k rounds of .38 Spl. a year in lever action pistol carbines, and that is where casting and reloading pay off.

[rintinglen]

Post Number 2 by countrygent stated the real reason that back in the old days--Pre-1980--Most of the "experts" like Keith, Sharpe, Nonté, recommended single, or at the most two cavity molds to avoid the boolit weight discrepancies that resulted from minor variances in the cavities. It was thought that these 1-2% weight differences would greatly and adversely affect accuracy.

Sharpe in his "Complete Guide to handloading," pooh-poohed the need, making what I personally believe to be the false statement that he could cast 300 boolits an hour with a single cavity. While you might make that rate in a short spurt (5 casts a minute, 1 every 12 seconds), IME the mold gets so hot that you are twiddling your thumbs waiting for it to cool.

Nonte joined Loverin in recommending a medium weight, single cavity mold as best for beginners to learn on. Loverin being a ladle caster, at least according what he was shown as doing in one of the 1950's Lyman Manuals, wrote an article on boolit casting that appeared in the 1st Cast Bullet Handbook Lyman manual. In it, he recommended a boolit mould casting about a 150 grain boolit for beginners. IIRC, Nonté wrote about the same thing in his book, "Nonté on handguns." I also have a memory of reading one of Keith's articles in the old Guns and Ammo where in he also made reference to single cavity molds as best for accuracy. You also find that advice repeated in the RCBS Cast Bullet Manual number 1, albeit by inference rather than direct statement.

But anyways, 50 years ago shooters seeking best accuracy were advised to either use a single cavity mold, or else make a small dent in the nose of a one cavity to allow visual differentiation to keep the products of each cavity separate. Back in the heyday of the single shot competitions at the end of the 19th century, shooters were advised to not only use a single cavity mold, but to shoot their boolits in the order they were cast!

Now I think these precautions are no longer needed. As previously mentioned, improved modern manufacture methods have made Molds that produce amazingly uniform boolits. Especially for handguns, I find anything less than a 4 cavity too much work to use, while 5-8 cavity aluminum molds like those available from MP Molds, Accurate, LEE or Arsenal make a nice pile of boolits pretty quickly. Unless you are a precision rifle shooter seeking Cast Boolit accuracy for Fortune and Glory, I don't think there's any need to consider casting onesies or twosies, unless that boolit style can't be had in anything else.

[Targa]

Lee is the main reason I have any two cavity molds. At the time I bought my 2 cavity Lee molds they were $20.00 a pop and they came with handles. I will say they are nice to cast with from a weight perspective and the ability to get up to operating temperatures very quickly.
With exception of a couple of .30 cal molds for my 30-30 Winchester, they are all .44cal and up.

[jdgabbard]

Those who think 1-2 cav molds are a remnant of ladle pouring have apparently never have seen an old H&G arsenal mold from the early 1900s. They ladle pour those bad boys too...

Honestly, it's easier to ladle pour a 1-2 cavity mold. But it's also doable with a 4cav. But, probably the biggest reason you didn't see more of them in the past is because of cost. More holes means more machining. More machining means the buyer has to spend more. And that probably wasn't in the cards for a large portion of the population.

The reason they're still around? Well, because of the same reason. The traditional mold makers (Lyman, RCBS, etc) have a bottom line to meet. They gotta justify the profit margin for every dollar spent. And on large molds they may just not think there is enough buyers to justify the cost. The custom mold makers are making the 4-8cav molds because they realize that is what people want, are smaller without the same overhead and fiduciary duties to stockholders. As such they can meet this demand without the need to charge as much as the larger companies. Then you have Arsenal, who does 1-5cav, because that is what he is setup to do. But charges enough to justify the options he offers.

[Gobeyond]

Do you know. [url]www.mp-molds.com. /url] @OP

[Larry Gibson]

As to a cast bullet for the 30 Carbine; I mostly use a Lyman 4 cavity 311316 mould. Lee makes a very good C30-115-FP (?) but not sure they make a 6 Cavity mould for it. I have cast a bajillion 311359s with a 2 cavity mould in years past.