Single or Double Cavity Rifle Mold?

[shotstring]

I have been playing with all the benefits of both types of molds for rifle calibers and decided to get some group input at this point before I aquire too many more rifle molds.

Single cavity supposedly disperses heat better, and since every boolit comes from the same cavity, more consistency should be attained and thus more accuracy.
But doesn't a double cavity mold just give you two boolits to chose from rather than one? If they are cast close to same weight/dimensions, then you simply have a 100% increase in casting speed. If they weigh differently, then you have 2 bullets to choose from and can still use it as a single cavity mold - just pick the weight you wish to cast and treat your double cavity as a single cavity mold. With a double cavity mold, if one cavity gets ruined, you still have a servicable mold.

But then the esthetics and simplicity of the single cavity mold pulls me back.....

What does everyone else prefer? My next purchase will be a Saeco mold, so I will have to order and wait to get it from Midway. Would like to make the most intellegent choice I can between single and double cavities.

[Ricochet]

I'll go for the double cavities. Singles are just too slow.

[MT Gianni]

[QUOTE=shotstring;251361]I If they are cast close to same weight/dimensions, then you simply have a 100% increase in casting speed. If they weigh differently, then you have 2 bullets to choose from and can still use it as a single cavity mold - just pick the weight you wish to cast and treat your double cavity as a single cavity mold.
"If you can keep your wits when all about you are losing theirs"
Those are some big if's. I prefer 2 cavity's though I have one 4 cavity Ideal rifle mold I like. You can always mark one of the cavitys with a punch to diferentiate between them. Gianni

[NVcurmudgeon]

[QUOTE=shotstring;251361]I If they are cast close to same weight/dimensions, then you simply have a 100% increase in casting speed. If they weigh differently, then you have 2 bullets to choose from and can still use it as a single cavity mold - just pick the weight you wish to cast and treat your double cavity as a single cavity mold.
"If you can keep your wits when all about you are losing theirs"
Those are some big if's. I prefer 2 cavity's though I have one 4 cavity Ideal rifle mold I like. You can always mark one of the cavitys with a punch to diferentiate between them. Gianni

I have single and double cavity moulds and prefer the doubles. With the doubles, as Gianni said, you can mark one cavity with a punch to keep the castings separate. To add orienting to your bag of tricks, you can mark the two cavities in different places on the boolit. Only one of my rifles is good enough to benefit from segregating and orienting boolits so far, and then only when shooting from a bench. For busting rocks and ringing gongs from field positions, it's just not worth the bother IMO, but if your mould is marked you have the option.

[Blammer]

Two cavity. You can "mark" one of the cavities so a 'mark' will appear on one of the boolits and you can easily 'sort' them. For accuracy testing.

Two cavity, cause when you are just plinking, you can make lots of plinkers and it won't matter where it comes from.

[Bent Ramrod]

If you're into production, the dual cavity obviously outperforms the single. However, I would like to see somebody who gets 100% more productivity with a DC over a SC. 75% certainly, maybe a little more if everything is going swimmingly.

Also, not every design is available in DC style, at least not anymore. This would be a factor as far as I'm concerned, as I'm convinced that somebody has designed the perfect cast boolit. I just haven't run across the mould yet:mrgreen:.

But I'm not givin' up!

[Shiloh]

Double cavity. A small dimple with a center punch or flex shaft tool to mark them if you so desire.
When one gets a rhythm going you can get a nice pile of boolits per casting session.

The upper Mid West winter is upon us and rifle shooting is all but finished for the season. I plan on doing more experimentation in the spring with boolits from each cavity of the molds to see how much of a difference there is, if any. No difference in the .357 with Double Cavity Lyman 35891 150 gr. wadcutters.

Shiloh

[shotstring]

Do you folks mark your cavities in the quarter/center of the base? (middle of base on one half when the mold is split)

[Shiloh]

Did mine on a driving band, thinking that it would be swaged out slightly when sizing and lubing. Just a slight dimple, enough to show up on the boolit.

The problem is that after loading, one cannot tell one boolit from another, so you have to keep them separate. Like you I'll wait to see how others mark them.

Shiloh :castmine:

[MT Gianni]

I use a SMALL dimple midway up the nose. Gianni

[NVcurmudgeon]

Small dimple halfway up the nose, and for the other cavity a small dimple farther up the nose. Actually this is my future plan, having used one dimple and two dimples in the two cavities. It works fine, but is overkill.

[35remington]

Double cavity, no question. Single cavity are maddeningly slow and my time is too precious any more.

If the bullet has a flat on the nose, I mark the flat on one cavity with a line or some such, with no alteration to the other cavity. I mark close to centerline but not so close as to leave a burr on the part line.

[joeb33050]

If you're into production, the dual cavity obviously outperforms the single. However, I would like to see somebody who gets 100% more productivity with a DC over a SC. 75% certainly, maybe a little more if everything is going swimmingly.


But I'm not givin' up!

Cast
Inspect
Weigh
Gas Check
Size
Size again-maybe
Lube
This is what I do to get 31141s with the bottom groove only lubed, sized to .309" and gas checked in a separate step.
It takes me, I'm guessing, twice as long for the rest as for casting.
Casting is only the beginning, and even id DC=200% bullets/hour, the TOTAL time isn't changed much, if I'm guessing right, only 17%.
joe b.

[9.3X62AL]

It sure seems to take a LONG time to fill a 1# coffee can with Lyman #257312's using a 1-cavity Ideal mould.

[walltube]

"....before I aquire too many more rifle molds."

How can you possibly aquire 'too many'?! HAR!

[dromia]

Two or more cavites, dimples on the nose.

I do use quite a lot of single cavities for hollow based boolits and they are slow, I ladle pour these.

[Ricochet]

I don't plan to sort or mark boolits from the different cavities of any of the numerous 6-cavity GB rifle moulds I've bought through this board. Don't think I will on the few double cavity moulds I now have, either.

[94Doug]

I also don't think it is a bad idea to get a one cav mould just to see how a particular boolit would perform in a firearm you own... then upgrade to multi if it works. I sure can't see loosing any money on it with the prices on ebay if it doesn't work out.

Doug

[BruceB]

Most of my rifle moulds are the two-cavity type, until we reach the over-.40 calibers.

94Doug has a very good point, about testing a design in a single-cavity mould and then deciding whether or not to proceed with that bullet. I've done this myself on a number of occasions, and he's right....the single-cavity mould will easily find itself another home as I go to a larger one with more cavities. I am VERY glad that Lee has now changed many of their rifle designs to two-cavity format, and I have several one-banger Lees that will be upgraded to two-holers.

I truly like my Lyman 4-cavity moulds, but unless we need thousands of bullets, they're not really necessary. However, another factor is that the bullets from the 4-cavs are very, very consistent in both weight and dimensions. Anyway, my 2-cavity jobs easily deliver well-over 400 bullets per hour, and that's an ample rate for the sort of shooting most of us do.

My RCBS 270-130 mould casts bullets which average almost exactly one grain apart from the two cavities, and this is the only current mould on hand in which I've marked a cavity. Using a very fine needle file, I placed a tiny (TINY!) notch dead-center on the nose of one block of one cavity. This gives just a miniscule tit dead-center on the meplat, and it's easy to see and feel. I have yet to try comparative grouping experiments using only bullets from each separate cavity, or between segregated bullets and mixed bullets from both cavities. Somehow, I don't think it'll make a gnat's behind worth of difference in our light-barreled M77 sporter.