LEE Case Mouth Flaring Die

LEE CASE MOUTH FLARING DIE


The LEE Case Mouth Flaring Die is a very unique application for a reloading tool, and makes one wonder, “Why did it take so long for someone to think of designing a tool in this manner?”

Reloading a straight walled cartridge case; like the 45ACP or .357 Magnum, etc. requires a 3-die set. The first die resizes (reduces) the outer case walls. The second die flares the mouth. The case mouth must be flared so a new bullet can be started into the case. Without the case mouth being flared, the heel of the bullet would catch on the case mouth, crushing the case mouth. OK, what about bottleneck cases like the 30/06, 8X57, 7.62 NATO, 762X54R etc? They generally require a 2-die set.

I say generally because the die makers assume reloaders of bottleneck cases will be loading jacketed bullets. Of course the die makers know some will be using cast bullets. Against that purpose; most (but certainly not all) die makers also produce a case mouth flaring die, more on that later.

The reason a jacketed bullet doesn’t require a flaring die is; the expander ball passes thru the case neck as the case is withdrawn from the FL die. The expander ball brings the internal size of the case neck up to .001 below the size of the jacketed bullet. The jacketed bullet expands the case neck the last .001, and that is enough bullet grip for proper ignition, and complete burning of a normal powder charge. However, what if the reloader wants to use cast bullets, or is concerned the sides of the jacketed bullet may be scraped by the case mouth during the seating process?

Cast bullets are much softer then jacketed. The hardest cast bullet will have a Brinell hardness of 30; most are softer. Jacketed bullets have a Brinell hardness of 100. Attempting to seat a cast bullet in an un-flared case neck will damage the bullet.

Boat tail jacketed bullets will seat easily in an un-flared case neck, however, the parallel sides of the bullet can still be scrapped. Flat base bullets can get a lot of scrapping on the sides. De-burring the case mouth with tools for such purposes will help keep bullet damage to a minimum. However, excessive de-burring can weaken case mouths.

Most major reloading tool manufacturers have cataloged a flaring die for decades. Traditionally designed flaring dies all seem to have two features. They are caliber specific, and are of rigid construction. Additionally, one company makes flaring dies that are specified for either “long” or “short” cartridges within a caliber family. These dies work OK, but a new flaring die must be acquired for each caliber family. Being rigidity constructed, they can flare a case mouth off center if the press isn’t in perfect axial alignment.


Adjustment piece, small flaring plug, large flaring plug, die body


Small flaring plug & large flaring plug


LEE case mouth flaring die in top of press


Ready to flare a piece of brass


Unflared piece of brass, notice the bullet will not start into the case mouth


Flared piece of brass, notice the bullet will now start into the case mouth


The LEE Case Mouth Flaring Die is a departure from traditional thinking and design. First, it is truly a “universal” die. Two flaring “plugs” are included, one large, one small. Between them, all calibers are covered. The plugs can float a bit once installed in the die body. Since they float, they will self-center in a case mouth; making sure both sides of the case mouth flare evenly.

It matters not whether one is flaring 7.62 NATO cases or 300 Winchester Magnum cases, there is plenty of adjustment in the LEE Case Mouth Flaring Die body. This one die covers all case lengths.

Need to switch flaring plugs? It’s the work of a minute to switch from flaring .38 Specials to flaring 45/70’s! The LEE Case Mouth Flaring Die can be ordered from any web based or catalog supplier of reloading tools for about $10.00 + shipping.

The LEE Case Mouth Flaring Die and LEE Decapping Die are two tools that I find indispensable. They should be on every reloader’s bench.