HK USP 45 Tactical VS FNX 45 Tactical – Full Comparison

If you're looking to buy a rock solid polymer frame 45 ACP handgun. The HK USP 45 Tactical VS FNX 45 Tactical are two most popular options on the market. One is a tried and true classic handgun and the other is a modernized 45 ACP.

This guide presents a comparison between the HK USP 45 Tactical and the FNX 45 Tactical side by side to highlight their differences and similarities, aiding you in making an informed buying decision.

Regardless if you're collecting firearms or buying one for defensive use. Check out these two firearms below:

HK USP 45 Tactical VS FNX 45 Tactical - Side By Side Comparison

Physical Dimensions

HK USP 45 Tactical

  • Length: 8.6 in
  • Height: 5.9"
  • Width: 1.26"
  • Weight: 32.8 oz with mag
  • Capacity: 12 (+1)

FNX 45 Tactical

  • Length: 8.6 in
  • Height: 6.5"
  • Width: 1.58"
  • Weight: 33.3 oz with mag
  • Capacity: 15 (+1)

Factory Barrel Specs

HK USP 45 Tactical

  • Length: 5.09 in
  • Thread: 16x1LH.

FNX 45 Tactical

  • Length: 5.3 in
  • Thread: .578" X 28 RH TPI thread

Magazine Capacity

The winner goes to FNX 45 Tactical for having the most amount of 45 ACP packed in a double stack magazine. Both magazines are readily available to purchase at around $50 each.

So if you need more, they are out there.

Optic Footprint

HK USP 45 Tactical

  • None

FNX 45 Tactical

  • RMR, Docter

When it comes to optic mounts, the FNX 45 Tactical is the winner here. The HK USP 45 requires special milling service to mount an optic. And yet there hasn't been any information that suggest the USP product line will be getting optic cuts.

However, the FNX 45 Tactical's mounting interface isn't as perfect when compared with what's on the market. One thing that stands out is that the optic plate doesn't lock onto the slide well, and it creates shear force on the optic screws.

Remember, the FNX 45 Tactical is released in late 2012. Back then, handgun optics were still in its infant stage.

Fast forward to 2023, most optic ready handguns feature very sophisticated mounting interface to ensure the best optic locking system to retain zero. 

Grip Comparison

Both handguns are large 45 ACP grip frame. Both are double stack, and the FNX 45 Tactical's grip is more modern and more comfortable in the hand than the USP 45 Tactical.

The USP 45 Tactical grip frame is slightly larger than the USP 9mm. It's serration pattern dates back to when it was first introduced in 1993. The grip texture gets the job done, but the ones featured on the FNX 45 Tactical has a lot more grip friction to prevent grip slip when shooting the gun.

The FNX 45 Tactical's grip flexes a lot more than the USP however, which can completely fail if ran over by a car. On the other hand, the USP 45 Tactical's grip is very rigid and hard to flex.

While the USP 45 Tactical's 1911 angle style grip is great for its generation, but the winner has to go to the FNX 45 Tactical. The definitive grip texture makes good contact, and the additional grip panels allow the shooters to custom fit their hand.

Each grip panel has different thickness, which can slightly change the grip angle for shooters who are looking to adjust their natural point of aim.

These grip panels are also serrated to reduce grip slipping.

Factory Trigger Performance

Both FNX 45 Tactical and HK USP Tactical are double action and single action handguns. These guns are designed for the military, which some contracts require these features.

For civilian use, both handguns provide adequate amount of safety with the heavy double action trigger pull, and the decocker to put a cocked hammer back down to double action.

For the most part, shooters will be using the single stage. Single stage trigger is easier to pull without adding finger strain to break the shot. Both guns have fantastic single stage trigger pull without any noticeable dislike. However, both guns have long trigger reset, and long pretravel to get the trigger back to the wall.

To reference what's a better trigger that doesn't do that, please check out the Beretta M9A4.

FNX 45 Tactical Single Action

FNX 45 Tactical Double Action

USP 45 Tactical Double Action

USP 45 Tactical Single Action

Both handguns feature trigger safety, and they are easy to disengage regardless the finger placement angle on the trigger shoe.


Both handguns feature high quality factory internal components such as the firing pin, trigger sear, magazine release button, trigger spring and others.

Take down is slightly easier on the FNX 45 Tactical because the user can lock the slide and just turn the take down lever without gripping the slide in awkward positions. The HK USP 45 Tactical requires the user to pull the slide almost half way where the take down pin can slide through the cut out.

Slide Release

The USP 45 Tactical has the better slide release lever than the FNX 45 Tactical. It's large and most users with various hand sizes can find that thing and hit it with no problem. For shooters who prefer to hit the slide after reloads, the USP 45 Tactical is much easier

However, it's NOT ambidextrous, and the large slide release can get in the way with the support shooting hand, which can cause the last round not locking the slide back.

The FNX 45 Tactical's slide release are ambidextrous and it's recessed, so nothing can accidently lock the slide when shooting. However, it's much smaller, and it can be a struggle for new shooters to manipulate the slide.

Shooters who prefer the FNX 45 Tactical should use the power stroke method to send the slide back into battery after each reload.

Magazine Release

The FNX 45 Tactical has the best magazine release ergonomics than the European style paddle magazine release lever.

Both are ambidextrous, but still, the FNX 45 Tactical is a push and release mechanism that most users can operate easily (either with thumb press or trigger finger press). The USP 45 Tactical is a bit tricky to get used to, and it's too small to operate when wearing thick gloves. (Support hand thumb press is the best without breaking the grip with the firing hand)

External Safety

Both guns feature external safety lever to safe the trigger or to decock the hammer. Both are very easy to operate, but the USP 45 Tactical only feature the lever on the left side, so it's not ambi.

Slide Serration

The FNX 45 Tactical has front and rear serration cuts on the slide, and the USP Tactical only feature rear serration cuts.

Users can easily charge the slide just by using the rear serrations, but doing press check is much easier with the FNX 45 Tactical. 

Missing front serration cuts on the USP 45 isn't a deal breaker. Users can add serrated tape to add more gripping friction to fix the issue.

Something about the HK USP 45's slide design regardless of its missing feature compared to modern day standard, it's still a eye catching classic design that tactical handgun enthusiasts keep coming back for.

Iron Sights

Both sights are suppressor height sights. The FNX 45 Tactical comes with factory night sights right out of the box. The tapered rear sight opens up the field of view a little bit more than the blocky rear sight on the USP.

USP 45 users can swap out the iron sights to something better.

Aftermarket Parts Support

At the time of writing this comparison guide, both guns have very niche aftermarket parts support, but they are definitely as readily available compared to popular guns like Glock.

The biggest accessory upgrade for the HK USP 45 is the M1913 rail adapter, and other OEM parts can be found on

As far as for the FNX 45 Tactical, there are only a few upgrades like optic plates and muzzle compensator. Nothing too crazy.

Here are the top 5 upgrades you can find for Glock 43X

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