JT Bullet Moulds’ .670 Round Ball Mould

JT Bullet Moulds’ .670 Round Ball Mould

Today I’d like to discuss a round ball mold I purchased from a small, independent manufacturer called JT Bullet Moulds.  The owner, Jeff Tanner, is located in England and produces these from solid brass.  What makes Jeff’s molds unique though, is that they’re essentially made to order in virtually any diameter you want.  I’ve purchased a pair of moulds from Jeff including a .670 that I’ll be reviewing below.


The mould itself is quite small, being a single-cavity model.  JT Bullet Moulds has a really clever design in their round ball mould; the cylindrical shape of the blocks eliminates unnecessary material which helps keep both the size and weight down, making it easier to cast with and cheaper to ship.  That’s particularly important when you’re dealing with a heavier material like brass.  Likewise, Jeff’s decision to design his molds to accept cheap, locally-available Lee Precision 6-Cavity handles rather than a more expensive proprietary design means you’re saving even more on shipping. Being as JT Bullet Moulds is located in England and I’m in Canada, that alone probably lowered the cost by $15 to $20.  These moulds also forego the traditional alignment pin systems used by competitors.  That’s because Jeff’s incorporated them into the shape of the blocks themselves, using a circular design that locks up really nicely around the entire circumference of the cavity.  This ensures a better seal, and will last a long time without requiring any lubrication or maintenance.

As I mentioned above, what makes JT Bullet Moulds unique is the fact that you can request virtually any diameter of round ball you want without having to order in bulk, or wait six months for production.  I ordered this .670 to make 12 gauge pumpkin ball loads for my shotgun, and had it in hand exactly two weeks after clicking ‘submit’.  That’s a pretty incredible turnaround time for a custom made mould coming all the way from England.


Due to it’s small size, these moulds heat up almost instantly, eliminating the need to pre-heat and the frustration of half-formed projectiles.  By my third casting I was already seeing perfectly filled-out round balls.  One thing I will mention is; if you’re casting large diameter projectiles like these .670’s, you’re going to want to use a high capacity melting pot as these things are pretty thirsty, and will drain your lead supply quickly.

Once the mould has reached temperature, the round balls generally fall out without much effort.  Some of the smaller diameter projectiles may require a bit of a tap, but these .670’s almost leap from the cavity of their own volition.  As there’s no sprue plate on this mold, once in a while they’ll stick at the pour hole, but experienced casters know that’s pretty much par for the course when casting round balls or buckshot.  When this happens I just use a pair of needle-nose pliers to pull them out by the sprue, and toss them in my quenching bucket.

Production rate is hard to gauge as it depends so heavily on the caster’s setup, but it’s no exaggeration to say I can churn out a few hundred per hour without breaking a sweat.  That’s pretty impressive for a single-cavity mould.  Further assist production is the fact that these are so light and easy to use; multi-hour casting sessions are nowhere near as taxing as some of my larger, heavier gang moulds.

Once the round balls are cast, it’s time to sort them and cut the sprues.  If you cast your own buckshot, this is essentially the same task on a larger scale.  A simple pair of flush-cuttters ($5 at any arts and crafts store) is all it takes to snip the sprues free of your castings with only a small, flat cut left in their place.


JT Bullet Moulds makes some of the finest custom moulds I’ve ever seen.  The build quality, design features and customer service are unmatched in the commercial sector, and far more affordable than any other custom manufacturer offers at the time of publication.  The round balls cast with these moulds are extremely accurate with excellent performance in my shotguns.  As an added cosmetic step, I choose to tumble my castings in corncob media using a vibratory tumbler; I find it smooths the sprue cut and any casting lines, as well as adds the classic ‘dull grey lead’ look that I like in my ammunition.  Bear in mind this is entirely optional, and I’ve loaded these straight from the mould without issue.

Bottom line; if you want a round ball mould, made from top quality materials, by a master craftsman who clearly cares about his product and his customers, JT Bullet Moulds should be your first choice.

You can find these moulds online at http://www.ballmoulds.com or by emailing Jeff Tanner at jeff@ballmoulds.com

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