Cavity # Preferences

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  • Last Post 12 May 2017
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BigMan54 posted this 05 May 2017

How many folks have a preference as to how many cavities they prefer in a rifle bullet mold. I have a # of old small block LYMAN single cavity that I like to use in .30 & 7mm. On the premise that only one cavity will cut out one or more variables. 

Any thoughts? 

Long time Caster/Reloader, Getting back into it after almost 10yrs. Life Member NRA 40+yrs, Life S.A.S.S. #375. Does this mean a description of me as a fumble-fingered knuckle-draggin' baboon. I also drool in my sleep. I firmly believe that true happiness is a warm gun. Did I mention how much I HATE auto-correct on this blasted tablet.

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David Reiss posted this 05 May 2017

It depends on what you are using the CBs for. If it is plinking, hunting, etc, then it doesn't make much difference. A lot of competitors use only one cavity molds or only one cavity of a multiple cavity mold. You are very correct in that using one cavity eliminates variables. It really depends on how much you believe in CB voodoo.  

David Reiss - NRA Life Member & PSC Range Member Retired Police Firearms Instructor/Armorer
-Services: Wars Fought, Uprisings Quelled, Bars Emptied, Revolutions Started, Tigers Tamed, Assassinations Plotted, Women Seduced, Governments Run, Gun Appraisals, Lost Treasure Found.
- Also deal in: Land, Banjos, Nails, Firearms, Manure, Fly Swatters, Used Cars, Whisky, Racing Forms, Rare Antiquities, Lead, Used Keyboard Keys, Good Dogs, Pith Helmets & Zulu Headdresses. .

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onondaga posted this 05 May 2017

BigMan54

From what I read on this forum about all number of cavity molds and the variables casters discuss, I don't see much difference between a 1 or a 6 cavity mold or any in between. The biggest variable is the skill level of the casters due to a lack of understanding about the thermodynamics if casting. There is actually nothing new in casting methods and no surprises about what works if you know what you are doing and do it well. So many facets of casting are irrelevant to consistency if you are a good caster. Bullet to bullet difference from a good caster is not statistically relevant. If you are a good caster, you know this because you do it right.

Gary

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RicinYakima posted this 05 May 2017

Due to an arm injury and arthritis in my hands, I prefer nothing heavier than an RCBS two cavity. While I could use an aluminum 4 cavity, pushing the sprue plate open is harder on may hands. When I set up to cast, I try to cast for 4 hours. That makes comfort a factor for me.

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MarkinEllensburg posted this 05 May 2017

I prefer 4 cavity. That said most of my casting is done with two cavity molds. It is what I have.

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TRKakaCatWhisperer posted this 05 May 2017

One cavity if it is for a match rifle.

4 to 6 cavity for pistol bullets like .45acp and .357mag.

otherwise 2 cavities is ok..

 

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JeffinNZ posted this 05 May 2017

I have an intense dislike for single cavity moulds.  My patience are not up to that.  That said I generally run two moulds at once to get into a rhythm. 

Cheers from New Zealand

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David Reiss posted this 05 May 2017

I typically use 1 to 3, one to three-cavities or 2 four to six-cavities at once. I too am not old enough yet to have developed patience enough to use one cavity molds. However I must admit I have a few dozen single cavity molds. Maybe as I become more serious about competing, I will become more anal and use as much skullduggery as possible.  

David Reiss - NRA Life Member & PSC Range Member Retired Police Firearms Instructor/Armorer
-Services: Wars Fought, Uprisings Quelled, Bars Emptied, Revolutions Started, Tigers Tamed, Assassinations Plotted, Women Seduced, Governments Run, Gun Appraisals, Lost Treasure Found.
- Also deal in: Land, Banjos, Nails, Firearms, Manure, Fly Swatters, Used Cars, Whisky, Racing Forms, Rare Antiquities, Lead, Used Keyboard Keys, Good Dogs, Pith Helmets & Zulu Headdresses. .

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Ed Harris posted this 06 May 2017

Since I retired I have gotten away entirely from iron molds which are prone to rusting. Giorgio reinforced this point with polite emphasis during my visit to his home in Italy a few years ago.  Upon returning home I frequently celebrated this discovery in toasting Garibaldi's Irregulars who could be accurately compared to Mosby's Raiders who operated in the region where I grew up as a boy in Virginia.

Today I use only aluminum molds from Accurate, NOE or LBT for the greatest majority of my shooting. Most often 4-cavity.

When I was still match shooting regularly I used bullets cast from gang molds.  I was fussy about visual inspection, particularly the bases.  I carefully inspected and weighed "match" bullets just to eliminate heavy or light ones deviating more than 1% from the mean weight.  I consider an extreme spread of ten bullets not over 1% of mean bullet weight acceptable.  

Well filled out bullets with good bases which weight checked and were lightly bumped to precisely fit the throat did as well for me in military and production classes as tediously cast single-cavity, nose-pour molds.  Fit is king.  Weight variation is the second cousin twice removed if the bullet is free of visual defects.  Consistent alloy and casting technique is the key to uniform weight.

With the affordable quick delivery of custom molds which "fit" I cannot see why anybody would frustrate themselves with cherry cut or "group buy" molds which only fit a particular rifle or handgun by random variations of chance.

Hint to Ric, I no longer use a gloved hand to open the sprue plate, but a solid rubber hubcap mallet from the auto parts store. Works better and is less tiring than the 1 pound lead hammer cast from the H&G mold.

 

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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Bud Hyett posted this 06 May 2017

I prefer a two cavity mold, this doubles the chance of getting one good cavity. Sounds simplistic, but this  happens. The first RCBS mold I bought was the 30-180-SP with d 50% of the group tight and 50% around the core five-shot group. Ed Doonan and I worked with this, marking the cavities to find the cavity dropping the better bullet. Separating the cavities showed one cavity to be far superior.

Shooting in several different rifles, sizing both .310 and .311, varying the primer, the powder choice and charge; the observation held true for all rifles except one. The "bad" bullet shot well in one particular Springfield when sized to .311. This proves the continuing observation there are no hard and fast rules in cast bullet shooting. 

Rifle Observations:

  • The need is for efficient, volume, repeatable weight, rifle bullet casting since I cast for two people..
  • Custom molds often are offered only in single-cavity and this limits your choice.
  • Each mold can cast well at a different temperature, mating two molds for efficient casting can be difficult.
  • I like brass molds, however, the first four cavity was very heavy and slowed my casting rhythm.
  • The greatest variable that I am finding is the pot temperature; even two custom molds made in serial sequence can cast their best at 25 degrees apart. 
  • My rifle mold choices when available; 1) Two-cavity brass, 2) Two-cavity meehanite iron, 3) Single cavity-brass, 4) Single-cavity meehanite iron. 

  Pistol Observations

  • The need for pistol bullet casting is less for repeatable close weights and more for volume,  therefore, three or four-cavity molds when available.
  • I am going for reasonable volume, therefore, I use two-cavity molds when that choice is the only one available. 
  • I sometimes use aluminum molds for pistol since they are lightweight.
  • My pistol mold choices when available; 1) Three or four-cavity meehanite iron, 2) Three or four-cavity aluminum, 3) Three or four-cavity brass, 4) Double-cavity meehanite iron ,aluminum, or brass.

I am in chemotherapy now and tire easily, two-hour casting sessions are the limit and then sort and size to rest. 

Farm boy from Illinois, living in the magical Pacific Northwest

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BigMan54 posted this 06 May 2017

I'm glad to see so much response. 

I started casting with single cavity molds. We had LYMAN 4cav molds when I was a kid. Back in the days when lyman cared for customers wants more than the corporate bottom line, you could get almost any bullet in 1,2 or 4cav blocks.  We cast 6.5 thru .35 cal. In four cav molds, we rarely got 4 good enough for accuracy shooting, with each cast. On the other hand my ancient 4cav 454190 almost never drops a bad one. Even from the 1st cast. Over the years I just collected the 1cav at gun shows because they were cheap. I also don't get to the Rifle Range more than 2 or 3 times a year. It's a hard drive across L.A. & up into the foothills dodging the stupid bicyclists.  I have some newer 2cav rifle molds that work great from lyman & RCBS.  But in some way not getting to the range often takes the pressure off needing a lot of rifle bullets. 

I can't cast for very long either.  My back gives after about 45 min.  My hands too.

It's H**L getting old.

Long time Caster/Reloader, Getting back into it after almost 10yrs. Life Member NRA 40+yrs, Life S.A.S.S. #375. Does this mean a description of me as a fumble-fingered knuckle-draggin' baboon. I also drool in my sleep. I firmly believe that true happiness is a warm gun. Did I mention how much I HATE auto-correct on this blasted tablet.

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Dale53 posted this 12 May 2017

I will hit my 82nd birthday in less than a month. I have LONG preferred multiple cavity moulds. I have iron, aluminum and brass from nearly all of the major players. Aluminum five or six cavity moulds are my favorites, in general. However, I have some DANDY four cavity iron and brass moulds that work really well. I have no problem with operating these, but my six cavity H&G #251 (.358 dbl ended W/C), while a wonderful mould, weighs nearly five pounds. That IS fatiguing for sure. So, I tend to pick my H&G four cavity iron for the .358 W/C #50BB instead.

I used to do marathon casting sessions, but now I limit myself to one pot (RCBS 22.0 lb. pot) and cast twenty pounds of bullets at a sitting (yeah, limited by age and personal condition). That is NOT a bad thing, tho'. I just cast more days in the week...

I have a dedicated casting area in my heated and cooled utility barn, so no serious time is involved in setting up. I just pre-heat my mould on the hotplate while my pot is heating. In thirty minutes I am ready to roll. By pre-heating, I get good bullets from the "git-go", so it is all pleasure. I can do a pot in an hour to an hour and a half (.45's run faster than .32's (:>)...

I competed with black powder cartridge rifles for fifteen years. I had a couple of custom four cavity moulds (aluminum) and had NO accuracy problems with the multiple cavities in spite of all the Naysayers...

These days, all I shoot are revolvers and pistols, but that is fun, too (:>)

FWIW

Dale53

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