Bullet mould size. .36 cal.

[Steve G]

How do you go about determining the correct dimensions for a bullet mould?  Lee makes a .360 and Lyman makes a .375

[StevenV]

Alot depends on barrel maker. Some have wider lands then grooves and some wider grooves then lands. I have found that smaller calibers can accept close to bore size balls  and maybe a bit bigger.  Larger caliber .50 cal/.54 cal. rarely approach new barrel dia.I have a .40 cal. that takes .395 balls and a .40 cal that takes .403 balls. Barrels are made by different makers. I shoot for one hole groups so more lead , less patch is how I load. Patch doesn't drop below .018. To answer your question, between .358 and .365 would be the size ball your looking for without knowing land/groove configuration. Steven V

[Steve G]

I measured it from land to land and it looks like .360

[rich pierce]

If you are comfortable unbreeching the barrel, remove the breechplug and oil the barrel. Pound an oversized ball like .440 into the muzzle with a wooden or plastic mallet. Cut off tgd flash, short start it and ran it though end to end. Now measure the slug. If it has sn odd number of grooves you’ll have to monkey around a little by paring off the lands.

Small calibers are easy to load with bore sized balls because the actual surface area is small. So I do not hesitate to go to full bore size if it’s to be used in competition.

I use an unbreeched barrel to work out patch/ball combinations right in the shop. Use a variety of ball sizes, patch thicknesses, and lubes to find one that will load and engrave the ball with patch weave markings and not cut.

Beware any raised burr at the breech where the plug faces up to the barrel when doing this. If you don’t want to mess with that, only ram the ball halfway then push it back out the muzzle by ramming from the breech.

[Seth Isaacson]

Wouldn't using something like Cerrosafe to make a cast of the the bore be an easier and less risky option than unbreeching the barrel and pounding an oversized ball through it?

[Daryl]

I measured it from land to land and it looks like .360

Anything from .350", which I use, to .360" will work just fine, given a good smoothed radius crowning job.
In my .36, I tested .360" balls I bought at rendezvous and they seemed to load just as easily as the .350's with
the same 8 ounce denim patch. I usually use 10 ounce (.022") in this rifle with the little ball, but grabbed the wrong patches.
It really made no difference in the shooting.

My .32's crown. I also used .311" and .320" round balls in it as well, same patch and 5/16" rifle rod.
Rich knows whereof he speaks concerning small bore, easy to load tightly.

[Marvin S]

You talking a revolver or a rifle? .375 ball is usually for a 36 revolver or a 38 cal rifle. If you can find a heavy metal rod that will slide into the bore you can insert it and then drive a soft ball in an inch or so and then flip gun over and use the rod to jack hammer the ball out. Just be sure rod is smooth and chamfered, May take a couple hits.

[Steve G]

It's a rifle. Hornady. 350 round balls judt roll down barrel

[Daryl]

Steve, with the normal .006" to .008" deep rifling in most .36 rifles, an 8 ounce or 10 ounce denim patch will be just perfect to take up the
slack between that .350" ball and the bottom of the grooves.  I prefer the thicker 10 ounce, but the rifle shoots really well with the 8 ounce too.
This is the .36 Rice bl.

[StevenV]

Steve G , since you have .350 already PM me with your address and I will send you some  .358,.360 and .365 balls you can try if you want. Who is the barrel maker? Steven V

[Marvin S]

It's a rifle. Hornady. 350 round balls judt roll down barrel

Are you allowing for a lubed shooting patch?

[Steve G]

Not sure who the barrel maker is.  It's a Jackie Brown rifle. I'm going to use pillow ticking patches with a Ballistol mixture for lube

[hanshi]

I don't know the maker of my .36 barrel, but it loads very easily with a .350" ball and .022" or .024" patch.  A larger mold may be worth acquiring.  It's already a tackdriver with its current load.

[Marvin S]

I used.355 in my GM barreled 36 but it was worn out. It’s since been rebored by R Hoyt to .38 cal so I’m using.375 balls now.

[WadePatton]

How do you go about determining the correct dimensions for a bullet mould?  Lee makes a .360 and Lyman makes a .375

.350 or .355 would be "standard offerings" but you can get any size mold cut. Some makers charge extra for custom orders, some only sell custom sized orders-therefore they all cost the same.  There's Larry Callahan for bag-molds and Tanner in England for brass molds.  I'd use store-bought or "borrowed" balls of various sizes to get started out and adjust patching for best fit. 

Then if  you decide that ball size is no good or you have a lifetime supply of some supreme patching of a fixed thickness, then alter the ball size to make that work. 

A ball of -.010" nominal caliber should roll down the barrel, we only shoot patched lead balls in rifles and bare naked lead balls in smoothbores (and those should be -.020" caliber or more)-but that's a different subject

'Tis better to have a smaller ball with thicker patch to make the right snugness for good performance because a thicker patch carries more lube than a thin patch. Also thinner patches can work fine and starting out loads, but often blow out as pressures increase with loading increases.  Blown patches will throw shots and degrade accuracy-so make it a point to find your patches.  Helps if you have clean ground 30-50' from the muzzle where patches fall.  A spotter might help too-they're that important when working up loading combinations.

Lot of us use denim for patching. If you try denim be sure to wash it and that it's 100% cotton.  Stick some fire to it and make sure it chars and does not melt.  Stretchy denim is a crime against nature, but also is the way of the overfed world. Don't let it in your bore. Petrol and plastics are two things we don't want in M/L bores ever.

Enjoy the project. Welcome to the forum. Note the search function where you might find great old discussions of 36 cal and other small bores. Some men are no longer here to repeat their input, but much of it is preserved by the forum and sometimes they say something different or differently and open minds can benefit.