Could a round ball about .001 inch less than bore diameter be used?

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Naphtali

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On FLINTLOCK sub-forum I posted a thread for lubricating a round ball to try my years old DOUBLER device. DOUBLER creates stochastic indentations that act on the severe air drag on smooth round balls, the thing that those pock marks in golf balls that add many yards to golf shots until the green is reached. If the DOUBLER really adds yards — that is, significantly improves retained velocity, significantly reduces ball deflection from side winds— could a larger diameter round ball about .001 inch less than bore diameter be used? Gene Gordner, the Kalispell, Montana, gun maker who created my beautiful matched pair of English-style percussion rifles, informed me that ramrod loaded conicals can use bullet diameters .001 inch less than bore diameter. This allows several-to-many bullets to be conventionally loaded before fouling becomes an issue.

Bullets carry lubrication with them as they travel up the barrel. Round balls are surrounded during such travel by lubricated patches. If the patch becomes an unnecessary unlubricated wad or card protecting only powder from lubricant, if pebbled surface of round ball run through a DOUBLER is dry lubed like what some hand casters use, the bullet diameter stolen by the patch is again bullet diameter. Incrementally sized new/used/loaned round ball molds are cheap in several calibers. if DOUBLER is no longer available, a facsimile can be made for chump change. My English-sytyled big bore rifles do not have cheaply available round ball molds available. I have used only mallet-loaded conicals in them. My "hunt cape buffalo in South Africa" fantasy is no longer possible. I cannot take the beating I practiced to take, and I don't want to. Mold makers offer, for example, many nominal .54-caliber round ball molds that change in .001-inch increments. My .72-caliber rifles don't have such easy availability.

So before I invest $200–250 for a .72x or .73x bullet mold, discussing things with experienced round ball users seems like a worthwhile idea.
 
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Uncle Miltie

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You have to try it. The main reason for patching is to keep the bore from leading. Obturation occurs with all projectiles but the chief issue with a roundball is the lower weight and length than a bullet of the same diameter. In the old days (before patching) projectiles were hammered down the bore to provide an interference fit and engrave the rifling during loading but powder fouling and leading caused folks to use a patch and smaller diameter projectile to compensate.
 
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Is your bore exactly .72?

.72 ball for a .72 bore is not .001 less than bore.

.73 ball for a .72 bore ain't going to work.

.719 is .001 smaller than a .72 bore.
 
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stochastic indentations
Be careful. This is a family forum, language like that should not be used here. 😉
As for the rest of your post, it reminds me of two PhDs arguing over which of them is the more PhD'er. Yes, I've heard those conversations. But, you are talking about a very tight fit. My take, is "no". Unless, you want to load without a patch. As for obturation taking place, IMHO, that is still a matter of great debate as to whether or not it actually happens.
 

Erwan

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I don’t understand exactly what you want really do with this…
There is still another solution if you don't want to use a patch: load powder, a felt pad, or semolina, and on top of it, load a greased and chewed ball. So you can use a bit smaller ball greased for a higher initial speed
To chew a ball, roll it between two files for wood.
Regarding golf balls and the reason for the dips and bumps: I don't think the Magnus effect has any influence on the trajectory of a round ball...
The felt wad or semolina can help to get a bit of better sealing...
That's the way we do for muskets (no rifled barrels)...
 
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My understanding is that a "bullet" obturates when it is pushed from the forcing cone into the rifling. The brief, slight resistance under pressure is what causes the obturation. A ML ball, whether patched or not, is already in the rifling, not subject to a forcing cone/chamber transition. Since the chain of events is different and the scientific laws that apply are different, I wouldn't expect the same result. The only simile I can think of is shot going through a choke. The constriction causes a brief delay and increased resistance which is why the shot often deforms at this point as it is squeezed and smashed together.
 

hanshi

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A lead ball patch does two important jobs. First it grabs the rifling grooves and seals (mostly) the bore from escaping combustion gases. It also prevents leading of the bore. Normally for rifles a .010" to .005" under bore diameter ball is used and a lubed patch works its magic. I see an unpatched ball in a rifle as an expediency when haste is called for. Accuracy invariably suffers without a patch. A smoothbore can do very well with a bare ball but that's another story. In my .45 rifle, for instance, I load a .440" or a .445" ball with a .024" lubed patch. Accuracy is precise with that load. Even with a smoothbore the load is a .600" ball with a .010" to .015" patch since no grooves exist to fill with patch material. Accuracy is excellent.
 
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I had B Hoyt rework a TC 45 cal barrel and it came out to .456. What size ball should I start with, already have .440, .445, .451 and .454.
 

Eterry

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IIRC, Lymans Black Powder Manual has slow speed pics of round balls showing obturation upon leaving the barrel, so it happens.
I am certain I read where the Magnus effect is NOT applicable to PRBs, hence Dimpling is superfluous.
I feel black powder is way too dirty to use a PRB with that tight a tolerance.

Good luck.
 

Uncle Miltie

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Be careful. This is a family forum, language like that should not be used here. 😉
As for the rest of your post, it reminds me of two PhDs arguing over which of them is the more PhD'er. Yes, I've heard those conversations. But, you are talking about a very tight fit. My take, is "no". Unless, you want to load without a patch. As for obturation taking place, IMHO, that is still a matter of great debate as to whether or not it actually happens.

My opinion is that no obturation takes place on a round lead ball.
Might want to read this book; it is a good one.
 

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