About Bullet Moulds

To better help you select the bullet that is right for your gun, you’ll find the manufacturer’s mould numbers, where appropriate, and the range of diameters for which each bullet can be sized, as well as other critical information, to our price lists.

Please, understand that bullet moulds are designed to drop bullets that are anywhere from .001″ to .004″ over the stated diameter because it is very difficult to manufacture a bullet mould that makes perfectly round bullets.  It is, however, easy to make a sizing die that is perfectly round. Therefore, most bullets benefit from a little sizing. The largest sizing diameter listed with each bullet is the diameter required to get a round bullet. A bullet may drop slightly larger, but wouldn’t be perfectly round unless sized to the maximum diameter indicated. You can always buy bullets unsized and unlubed and lube them yourself. But, I would try them sized and lubed at their maximum diameter first, if it were me.

And generally, I don’t recommend sizing a bullet down more than .003″ from its as-cast diameter. All of that displaced metal has to go somewhere and that somewhere is the lube grooves. Inadequate lube can cause leading in situations where there shouldn’t be leading, so let’s not go there.

It is important, however, to match the diameter of your cast bullet to the critical dimensions of your particular firearm. This is covered in the section under “How do I determine what size my bullets should be?” If you’re still undecided, discuss it with me when you order.

Something else you need to keep in mind – advertised bullet weights are estimates made by the mould manufacturers, based on the exact mould they used, the alloy they used, the conditions they cast in, etc. The actual bullet’s weight, after I cast it, is rarely exactly the same as the advertised weight. Every mould is slightly different as well as casting conditions and that’s okay. What’s important to remember is that accurate bullets have very low weight and dimension variations. You won’t have good accuracy if the bullets you buy vary greatly in weight, one from another. That’s not the case with my bullets.

For example, the 45 caliber LBT 545 grain Postell mould that I have drops a bullet weighing between 543 and 547 grains. It’s still known as the 545 Postell and is one of our biggest sellers with outstanding accuracy. It’s also one of the many Big Bore bullets that we weigh segregate, giving you < one grain weight variation per box of 50. You’ll find that even our bulk bullets will have at most a slight variance in weight, one from another. It all has to do with the consistency of my casting methods. Go ahead, weigh them and see what I mean.

~Montana Bullet Works ~

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