Single vs Multi cavity Molds

[runnin lead]

I am thinking about a mold for my 45-70 Marlin , 400-425 gr.
All of my casting for 400+ gr bullets has been with single cavity iron molds,what can be expected to get good quality bullets from a multicavity mold & about how many cavities would work without having to wait forever for the 400 gr + bullets to cool.
If having to wait forever for cooling or cast 1/2 culls out of a 4 or 5 cavity mold it would be no time saver.
For the most part I would not have to be as fussy with these as I would have to be with bullets that are going 500 m or a 1,000yds, out of the Marlin probably
200m & may also try as a 200m chicken load out of my Sharps.
This would be an aluminum mold,one of the NOE group buys.

[quasi]

Single cavity bad, multi-cavity good.

[deltaenterprizes]

Single cavity for accuracy, multi cavity for volume.

[damron g]

Most 4 cavity rifle molds i have shoot well enough to not use the single cavity versions anymore.
My 311299 4 cavity has one hole that cast lighter by 2 grains and a bit smaller.I was all worried about this,but the bullet seems to land it the group.

I think two cavity molds are the answer for better production. Just mark cavities with small index marks on the meplat where it is out of the way and segregate them.Its like a two cavity single cavity mold!

[Dale53]

I shot BPCR Silhouette for fifteen years. All of the time I was raising a family and working full time. To get the practice I needed to be competitive, it was necessary to try multi-cavity moulds. I had NEI make me a four cavity aluminum mould and the bullets from all cavities did not vary more than + or - .6 of a grain. That was for .40 caliber 422 gr bullets. They shoot slightly over a minute of angle to 500 yards (as long a distance as I have to shoot). That was done with a 20 power scope off a bench for testing purposes and represented 10 shot groups with full black powder loads.

LBT made me a four cavity mould and utilized some different ideas of mine and Veral's and it gave equally good performance.

I never looked back. Conventional wisdom states that for accuracy you need single cavity moulds. I soundly disagree with that, if you are happy with minute to minute and a half accuracy at mid range distances with black powder.

I recently got a MiHEc six cavity pistol mould and carefully taking a bullet from each cavity showed a spread of + or - .2 (two tenths) of a grain between all six cavities. You just don't get any better than that. Properly operated CNC machines can do wonderful work.

Dale53

FWIW
Dale53

[BruceB]

My experience parallels Dale's.

Although I've never shot BPCR, I HAVE compared the output of a lot of moulds, and the multi-cavity Lyman, NEI, SAECO and LBT molds in my possession drop bullets with VERY little variation, cavity to cavity.

This is true to such a degree that I actively seek out the multi-cavity moulds in preference to the singles. I have no experience with Lees beyond their regular two-cavity moulds, but even there, there's little to quibble about.

This, coming from someone who once piously stated on this very Board that, although I could see the utility of multi-cavity casting for those lowly and plebian HANDGUNS, the right and proper Zen state of my rifles preferred, nay, DEMANDED, that their bullets be cast with excruciating care and magical incantations, ONE-at-a-time......

Bull.

The only difference is that the bullets are cast faster. Quality is every bit as good, and I've replaced a goodly number of singles with same-bullet-design moulds that cast three or four bullets per filling. Quality is a wonderful thing, but quality PLUS much-greater production is even more wonderful.

[runnin lead]

Hmmmm, maybe a 3 holer, still thinkin about all that moulten lead heating that mold up &then having to cool.
Have a 4 cavity LBT , cast great but those are 180 gr. .310.

[Echo]

Don't be afraid to cool the Al mold down by laying it sprue-side down on a sopping wet shop towel and letting it steam for 5 seconds. I do it with my 6-bangers.

[mooman76]

I don't mind a SC mould for something I don't put allot down range like 45-70. If you aren't real picky about your bullets(I'm not) multi cavity are usually fine.

[Bret4207]

All else being equal, quality of the castings is entirely dependent on the guy running the mould. If you can cast near perfect boolits witha single cav mould, then once you get the multi cav mould figured out you should be able to cast equally good boolits. As I said, that's assuming all else is equal.