Cup & Core vs. Monolithic Copper vs. Hard Cast

Cup & Core vs. Monolithic Copper vs. Hard Cast

Posted by Frank Melloni on 24th Apr 2023

Written by guest contributor, Frank Melloni

By my count, Underwood loads over 300 different projectiles across an immensely wide array of cartridges. However, if you boil it down, they fall into three general categories.

1. Cup & Core

2. Monolithic Copper

3. Hard Cast

If you are new to premium ammunition, this might all be a tad confusing, particularly when it comes to matching similar-weight projectiles to a given task. Here’s the skinny on this trio:

Cup & Core

9mm-luger-115-grain-tac-xp-sku-160-18668.jpgCup & core construction is by far the most common form of bullet on the market. Bullets of this nature start off as a copper cup and have a lead core pressed into them as they are formed into their final shape. These are your FMJs, soft points, etc. The benefit of these projectiles is that they are mass-producible and, for that reason, inexpensive. The downsides to consider are jacket separation upon impact and issues with barrier penetration. However, quality bullets seldom experience this, and if all you are doing is banging steel or punching paper, these are likely your ticket.

Monolithic Copper

As the prefix suggests, these are made of one material; copper. By using solid copper, the chance of jacket separation is completely avoided, and these projectiles will perform better against intermediate barriers. As these are produced through CNC machining, sharper angles and more intricate designs can be made, but that additional machining comes at an expense.

Hard Cast

Hard-cast lead bullets are used when you are looking to pack as much weight into as tight a package as possible. By substituting a copper jacket with, in essence, more lead, the same-size bullet gets dramatically heavier. The lead used in these pills is alloyed with a blend of antimony, silver and/or tin, making it substantially harder than the common variety. Pick these when maximum penetration is your goal, particularly in heavy revolver rounds.