TFB Review: MP5 Heckfire Trigger by ShootingSight

Nicholas C
by Nicholas C

When it comes to roller delayed blowback guns like the MP5 or G3, your options for triggers are rather limited. You can either buy another German trigger or have someone polish a factory trigger hoping for better results. Well, ShootingSight came out with their Heckfire drop-in trigger for MP5s and G3 clones. Let’s take a look at it.

MP5s @TFB:

ShootingSight Heckfire Trigger

ShootingSight’s Heckfire trigger is a drop-in trigger. It is housed in an aluminum cassette that is anodized red with ShootingSight’s name and Heckfire laser engraved into the sides.

The Heckfire trigger is almost ready to go out of the box. You need to install the ejector lever, ejector lever spring and ejector lever axle pin. I opted to transplant these parts from my HK SP5.

Removing those parts and reinstalling them into the Heckfire was effortless.

The Heckfire trigger has ambidextrous selectors that are bolted to the safety axle.You need to remove the right side in order to remove the safety axle so you can install the trigger cassette into your H&K trigger housing.

Then it is a simple matter of dropping the trigger into the trigger housing.

One minor issue is a cosmetic one, the selector levers do not cover up the holes in the factory H&K German trigger housing. You can see some of the red anodizing of the Heckfire cassette.

If you have an SEF lower then the gap is less noticeable.

Using the Heckfire Trigger

ShootingSight claims the Heckfire is a 5lbs trigger but I was getting closer to 4 lbs on average.

I removed the 9mm ejector and swapped in the ejector from my SAR8 HK91 clone. The Heckfire trigger is fantastic. I was able to make shots out to 600 yards with little effort. I put the trigger in my Magpul trigger housing so I could keep the factory trigger in the factory trigger housing. Now I can simply pull the two stock pushpins, remove the stock and then swap lowers.

I did experience one strange issue with the Heckfire and my SAR8. It does not seem to hit the firing pin on my HK91 .22LR conversion kit. I have to resort to using my factory trigger for the .22LR conversion kit.

Final Thoughts On The ShootingSight MP5 trigger

The Heckfire is exactly what I want in an MP5/G3 trigger. It has a short take up, light break and a short reset. There is a bit more reset though and you have some slack that you have to take back up after you go to reset. I would have preferred a single stage trigger but it is not a priority just merely a personal preference.

At the time of this review, ShootingSight no longer offers their trigger with the safety selectors you see in my photos above. They have made a new design that is more aesthetically pleasing.

HECKFIRE trigger for MP-5, HK 91/93/94, G3, Clones.

2-stage trigger with around 5lb total pull. Drop-in to all lowers.

The updated selector levers work for all lowers (you no longer need to tell us if it is an SEF or an AMBI lower) and they cover the selector lever hole in the lower so you cannot see the red through the hole (which is an improvement over the original selector levers). Our kit includes three selector levers: Left, Right, and Delete. This allows you to make your gun into: AMBI, or Left-hand only, or Right-hand only.

If you have the older selectors, you can email ShootingSight and they will send you the updated selectors. ShootingSight also offers their trigger bow in silver or black.

I reached out to ShootingSight and got a set of replacement selectors.

Replacement selector next to the original aluminum selector.
The new selectors are injection molded.
Selector delete, original aluminum selector and right side selector.
You can see the difference in selector lengths here.

The Heckfire retails for $399. It is not cheap but it is a solid option for upgrading your roller delayed blowback firearm with a better trigger. For more information, go to their website.

Nicholas C
Nicholas C

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6 of 11 comments
  • Aono Aono on May 26, 2022

    What other fancy triggers have you tried Nick? I managed to snag an SP5 and I'm not eager to make major changes to it, but am also a trigger snob and the standard one leaves a lot to be desired. I've wondered about how things like the Franklin binary trigger. Is this Heckfire the best one you know of?

    • See 3 previous
    • Cal.Bar Cal.Bar on May 27, 2022

      @Nicholas C I (sadly) have to concur. I've sent MULTIPLE HK's to him. Some turned out well. One turned out intermittently FULL AUTO! (sent back to him to be fixed) and my MPX has a nice crisp 3 lb trigger pull with NASTY trigger slap (and is far too easy to bump fire now).

  • Tonka Tonka on May 26, 2022

    I’m sure it’s a great trigger, but the name is so ridiculous. I literally heard an elderly checkout lady say “Heckfire” today just a few minutes after reading this article/name.