Lee Precision 90590 Factory Crimp Die 300 Blackout

The Lee Precision 90590 Factory Crimp Die for 300 Blackout is a specialized reloading die that takes ammunition consistency to the next level. Unlike standard seating dies, this tool applies a firm crimp that holds bullets more securely in the case. If you're loading 300 Blackout ammunition and want tighter shot groups, this die addresses a real problem: loose or inconsistent bullet seating that causes velocity variation and scattered groups downrange.

Here's how it works: the collet mechanism squeezes the case mouth into the bullet's crimp groove with precision. That firm hold means pressure builds uniformly before the bullet moves, creating a more consistent pressure curve throughout the firing sequence. The result is the kind of accuracy improvement that shows up on paper or steel. Interestingly, even bullets without a traditional crimp groove will benefit from this die's approach, making it a versatile choice for handloaders experimenting with different projectiles.

The 90590 fits any standard 7/8"-14 reloading press, so if you're already running a common single-stage, turret, or progressive press, you're ready to go. (You'll need a shellholder, sold separately, sized for your 300 Blackout cases.) This is one of those tools that separates serious reloaders from casual ones—the kind of attention to detail that separates minute-of-angle groups from random strings on a target.

Key Features

• Collet-style crimp mechanism grips the case mouth firmly for consistent bullet hold
• Improves accuracy by establishing uniform pressure buildup before bullet movement
• Works with standard and non-grooved bullets
• Compatible with all 7/8"-14 threaded reloading presses
• Reduces velocity variation for tighter, more predictable shot groups

Specifications

Frequently Asked Questions

Will this die work in my reloading press?

Yes, if your press has a standard 7/8"-14 die hole. That's the common thread size found in almost all current single-stage, turret, and progressive presses. You'll need the appropriate 300 Blackout shellholder, which is available separately.

What's the difference between this and a regular seating die?

A standard seating die places the bullet in the case but doesn't apply a firm crimp. The Lee Factory Crimp Die uses a collet to squeeze the case mouth around the bullet with precision, which locks the bullet down and produces a more uniform pressure curve when fired. This results in less velocity variation and tighter groups.

Do I need to use bullets with a crimp groove?

No. While bullets designed with a crimp groove will work perfectly, Lee's testing shows this die improves accuracy even with standard bullets that have no crimp groove at all.

What comes in the box?

The 90590 includes the crimp die body. A shellholder sized for 300 Blackout is not included and must be purchased separately if you don't already own one.