Strike Industries AR Mega Fins Key-Mod Handguard Rail

Strike Industries have done it again with another ridiculously low priced accessory. The new AR Mega Fins handguard costs $99 for 7″ / 9″ / 10″ lengths and $130 for the 11″ / 12″ / 12.5″ / 15″ lengths. It has a slim design and is described by the company as feather weight (7”: 5 oz 9”:5.8 oz 10”6.4 oz 11”: 7 oz 12”: 7.6 oz 12.5”: 8oz 15”: 9oz).



The name “Mega Fins” is derived from its design which has internal fins to draw heat away from the barrel/chamber and into the handguard. This has the significant advantage of keeping the action cooler and reducing the chance of cook-offs or other thermal failures, but the tradeoff is that the handguard will heat up quicker. Like with other lightweight slim metal handguard, sustained fire will require the use of gloves. We still have not figured out how to circumvent the first law of thermodynamics 😉



The Mega Fin has a top picatinny rail and seven keymod rails at 45-degree angles. Ridges run the length of the rail for better grip. A barrel nut tool is included with each rail.


Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • Doop

    Does it free-float? The fins look like they may contact the barrel if the handguard flexes.

    • Chris Hale

      Would that internal fin system even help with cooling if it didn’t contact?

      • Clint Notestine

        i guess if the barrel nut acts as a heat sink that leads to the handguard the fins would help

      • Mystick

        Being air-cooled, it increases surface area and hence conduction.

    • cmorrow

      It’s really hard to tell, but it looks like it still floats, but those fins are probably very close and likely touch with any flex like you mention. Their heat-sinking properties are probably most effective closer to the action as the fins likely touch the barrel nut, so the heat would transfer from upper receiver to barrel nut to near end of rail to far end of rail. That’s just my guess.

    • Ian

      The barrel is going to move a lot more than the handguard but even a one inch diameter barrel probably will never contact it. So yes, it’s free floating.

      And @cmorrow, heat doesn’t really transfer from the upper through the barrel nut to the handguard unless the barrel nut is aluminum which is unlikely in this scenario.

      • cmorrow

        Gotcha, that makes sense too. Do you think the fins just act to dissipate radiant heat from the barrel then?

        • JackNco

          Aluminum transfers heat 27 times faster than air and arguably is mor eeffective than copper in some respects…

          • steve

            …what respects would those be?

          • RocketScientist

            Copper (k =~ 400 W/mK) is flat out better than aluminum (k =~ 200 W/mK) for heat transfer, no ifs/ands/buts. Aluminum has the edge in many OTHER mechanical properties though (strength, weight, etc). In automotive applications aluminum radiators cool better not because the aluminum transfers heat better (it does not) but because the higher tensile strength allows for thinner-walled tubes of more efficient shape to be used, overcoming the defect in thermal conductivity.

    • Paul Epstein

      Having looked at the site, it’s incompatible with barrels over a certain outer diameter so they’re very close if not touching.

    • Cymond

      Arguably, the fins will make the handguard more rigid. Maybe that’s part of it’s light weight, just as a fluted barrel is more rigid than a round barrel of the same weight (or lighter weight than an equally rigid barrel).

  • cmorrow

    Pricing for 7-10″ starts at $99, the 9″ is $119, the 10″ is $125. There are similar price increases for the 11-15″ rails. A 15″ is $155. Still good prices though.

  • Zius Patagus

    Geez, everybody knows that fins are always better. Fish-no fins, sink, fins=more better. Old cars-no fins ok, fins=more better. Handguards no fins-ok, fins=more better. Simple law of finsics.

  • Nadnerbus

    I don’t get it. The whole point of a hand guard is to guard your hand. This is a heat sink. An AR isn’t a high volume of fire weapon, at least not to the point of cook offs. I don’t want my hand guard pulling heat out of the barrel and into my hand.

    I have a a scout rail on my mini 14 that lies directly on the barrel. Just a string of ten or 15 rounds in under a minute will heat it up pretty good. It is not a good thing to have on a combat rifle, in my opinion.

    • Mystick

      They are if they are capable of full-auto fire. In fact, cook-offs are a big problem for AR’s in that respect, as is accelerated barrel wear and gas-tube fouling with bad ammo. There’s a video around demonstrating that(as a secondary purpose)…. after several mags FA, they start to cook here and there, and there are also cycling issues from fouling. I’ll post it if I can find it.

      • Anonymous

        It’s outright impossible to get a cook-off…if the weapon is getting too hot to be handled by the shooter halfway before chamber temperatures reach the auto-ignition point. If you can’t hold it, you can’t shoot it.

  • mikecl

    I will know soon enough about the heat transfer, bought 1 today.Can’t beat the price….don’t feel like spending 300 + on a rail.

    • Gary Patterson

      Ordered one also, bought upper from and wanting to get out to range soon as i finish build.