If you have ever seen Hornady GMX or SST ammo on the shelf, you may have wondered which is better. While both of these bullets are manufactured by Hornady and share some similarities, they have several key differences that hunters should be aware of.
SST stands for Super Shock Tip, while GMX stands for Gilding Metal Xtreme. The SST bullet is a lead core projectile built for long range shots on small to medium sized game. GMX is a copper alloy bullet designed to penetrate deeper on large game with focus on complete pass throughs.
In this guide, we’ll discuss the key differences between Hornady GMX vs SST and which one you should choose for hunting or reloading.
Hornady GMX vs SST Ammo: Key Differences
- Material – GMX (copper alloy), SST (lead core)
- Expansion – GMX (1.5x), SST (1x)
- Weight (.308) – GMX (180 gr), SST (165 gr)
- Cannelures – GMX (2), SST (1)
- Hunting – GMX (large game), SST (medium game)
Ballistics
The ballistic output of the GMX and SST rounds perform quite differently. The GMX round is designed to offer a higher level of terminal performance, thanks to its mono-metal copper alloy construction. This bullet structure allows the projectile to expand rapidly upon impact, creating a larger wound channel and increasing the chances of a quick, humane kill.
On the other hand, the SST round is designed to offer a flatter trajectory, which can make it easier to hit targets at longer ranges. However, the SST bullet is not as likely to expand upon impact as the GMX bullet. SST rounds are offered in high FPS, but lack the overall penetration due to the bullet makeup.
Bullet Weight
Another key difference between these two rounds is their bullet weight. The GMX round typically comes in a heavier bullet weight than the SST round, which can have an impact on its recoil and trajectory. A typical .308 bullet in GMX is around 180 grains, where as the same SST bullet is closer to 165 grains.
The heavier bullet weight of the GMX round can also increase its penetration power and make it more effective at taking down larger, tougher game. This all reverts back to the bullet construction, with GMX being a copper alloy and SST having a lead core.
Here’s a great video showing the differences between Hornady GMX vs SST
Video from Hornady Youtube Channel on the GMX Bullet Design
Expansion
When it comes to bullet expansion, the GMX round is the clear winner. The gilding metal construction of the GMX bullet allows it to expand quickly upon impact, creating a larger wound channel and increasing the chances of a successful harvest. This expansion can be up to 1.5 times greater than its original diameter.
The SST round, on the other hand, is designed to retain its weight and shape upon impact, which can make it less effective at taking down game. It’s still a solid choice for hunting medium sized game though, and the ballistic tip and lead core are adequate for penetrating to achieve a clean harvest.
Range
If effective range is sought after, the SST round is the superior choice. The flatter trajectory of the SST round makes it easier to hit targets at longer ranges, whereas the GMX round is typically better suited for closer ranges.
Both bullets contain cannelures for improved accuracy and better mating to the shell casing, but GMX bullets go one step above with 2 cannelures over SST’s 1. Both have boat tails for improved aerodynamics, so accuracy at effective ranges is relatively the same.
Hunting
So, when should hunters use the Hornady GMX and SST rounds? The GMX round is a great choice for hunting medium to large game at closer ranges. It excels for elk, moose, caribou, and bear. Hornady developed the GMX bullet to penetrate adequately, even when the animal isn’t broadside. If you hunt large game, GMX is the right choice.
The SST round is better suited for hunting smaller game at longer ranges. The perfect scenarios where SST should be used are plains antelope and long shots down senderos for whitetails. The SST is designed to penetrate light skinned animals, which is perfect for most deer hunting.
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Bottom Line: Hornady GMX vs SST
The Hornady GMX and SST rounds are both excellent choices for hunting ammunition, but they have several key differences that hunters should be aware of. The GMX round offers a higher level of terminal performance and is better suited for taking down larger, tougher game at closer ranges, while the SST round is designed for flatter trajectory and better for taking down smaller game at longer ranges.
It’s important to consider the type of game you’ll be hunting, the range at which you’ll be shooting, and your own personal preferences before making a decision between GMX vs SST. To keep it simple, choose SST for deer hunting and GMX for anything larger.
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