Gear Review: Strike Industries Mega Fins Key-Mod Handguard

Free floated Key-Mod handguards seem to be all the rage. A bunch of companies make them. I’ve had the pleasure to try out a few, and over the last few months I’ve started to form an opinion of them as a whole. Mostly, I like them. As a guy with small hands, I can certainly appreciate the slimmer profile provided by not having Picatinny rail sprouting from every surface, and I generally enjoy a lighter gun whenever possible. Strike Industries has a Key-Mod handguard that features a cut out for an A2 sight that claims to be lightweight, durable, and endlessly modular thanks to Key-Mod as part of their Mega Fins line of handguards. I got the opportunity to try it out, and I’m mostly a fan . . .

Fresh out of the box, the Mega Fins rail immediately impressed me with how lightweight it was. My fairly reliable food scale registered it at 7.25 oz by itself, and 9.30 oz with the barrel nut. Strike Industries shows 9.20 oz on their website so I give them props for including their barrel nut in the overall weight, as more dishonest manufacturers might neglect that. My scale showed it a tenth of an oz heavier, but that’s close enough for me, and not something I’d ever dock a company points on in a review. Long story short, this thing is pretty dang light, but seems very sturdy.

The second thing I noticed was the “fin” texturing that covers every surface of the aptly named Mega Fins handguard. SI says this helps aid in heat dissipation from the barrel, a notion I’m not really qualified to argue with using any hard data. In my testing, I ran some pretty quick strings of fire, and I didn’t feel that it cooled my barrel any faster than any other free floated Key-Mod handguard. And while I flunked out of engineering before ever taking heat transfer classes, I have ripped apart a pretty decent amount of computers filled with heatsinks, and I’m pretty certain that for these fins to have an effect on the barrel, they’d need to actually touch the barrel. That said, they provide a nice texture for bare handed manipulation.

The last thing I noticed before I mounted the Mega Fins to my Palmetto State built upper/lower was that the Mega Fins is an octagonal shaped handguard which allows for a Picatinny top and seven (!!!) sides for mounting Key-Mod attachments. That’s a whole lot of rail estate, and does give you the option to run things like lights in a more ergonomically sensible place. I like options and the Mega Fins certainly delivers.

Installation is about as snappy as any other FF handguard out there. Once you have a bare upper, do as the book says, use a bit of moly grease, spin the new barrel nut on, torque it down using the included wrench, and install the handguard. The reality deviates from the book every so slightly as you need to time the barrel nut just so. That process means torquing the barrel nut, removing the upper from your vice, sliding the handguard in place, checking the timing, removing the handguard, placing it back in the vice, unscrewing the barrel nut, adding an included shim, torquing the barrel nut, and you see where this is going right? It is a painstaking process, and one that rarely goes right the first time. This is not isolated to just Strike’s handguard, and I’ve had this problem with every free floated Key-Mod system out there. The best one I’ve used so far is Noveske’s NSR, though it is a bit heart wrenching to wail on your upper with a torque wrench until everything fits properly. The SI system works, and I’ve got not doubts that it is solid, but you should be prepared to set aside a few hours to do this job right.

One hilarious outcome of this was that I found out that SI’s included barrel nut wrench is precisely calibrated to 40 ft. lbs. of torque. I know this because at anything over 40 ft. lbs., the wrench twists into an ugly paperweight. If you’re planning on installing one of these, get yourself a set of crowfoot wrenches that fit your torque wrench. Sears will take $50 and you’ll never worry about this again. Or you can put a big adjustable wrench on it, and Kentucky windage your way to a torqued upper.

Once everything is timed correctly, it is time to take advantage of one of the big selling features of this handguard, the ability to use an A2 style gas black. Since the Mega Fins handguard is specifically designed for an A2 style gas block, I had to go get one, and cheap bastard that I am, I borrowed one from a coworker. I mention this specifically because the aforementioned A2 style gas block didn’t belong to me which presented an issue during installation.

As you can see, the borrowed A2 sight is a.) positioned backwards in this photo, and b.) sporting a riveted sling mount. I wasn’t comfortable removing that rivet strictly for a photo opp, so I was unable to actually install the A2 style gas block. I measured a bunch of things, and I’m 100% confident that if your A2 gas block doesn’t have a sling mount on it, this whole thing fits perfectly. Unfortunately, I didn’t get to test that out. I also tried to make it come up from the bottom, and no dice there either.

I went back to using the factory mounted low profile gas block for the duration of my test, and I’m happy to report that everything works well. One unadvertised usage with the Mega Fins is for those using switchblock or adjustable gas blocks. This handguard should give you the unfettered access you desire to make adjustments to your gas system while still having a long handguard for various accessories. The particular model I tested was their midlength gas system 13.5″ inch handguard, though they also offer a 12.5″ handguard with a cutout for a carbine gas system.

Those who care about details look away now. As you can see from the picture above, depending on your particular upper, and how many shims are required to time this bad boy, you may find yourself with an unsightly gap between upper receiver, and handguard. Functionally, this presents a major problem if you’re using a Picatinny mount that requires a flawless joint between the upper and handguard as the spacing between sections is off. Normally, I use a Burris P.E.P.R. mount to time free floated handguards as it allows me to bridge the gap between upper and handguard by clamping one end on the receiver, and the other on the handguard. With SI’s handguard, I was unable to do that, so I had to go by feel and eyeballs to make sure everything was coplanar. From an aesthetic standpoint, it is a bit unsightly. There are plenty of people who won’t care, but some will consider this a deal breaker. We present, you decide.

Lastly, a note on durability. I’m downright mean to the gear I test. Sure, my Garand is lovingly cared for, and some day, a finely crafted 1911 will sit in my safe free of debris, carbon, and lint with a perfect bit of backlighting. But for my “duty” guns which encompass every AR I own, and any pistol that contains polymer, I beat ’em up a bit. I expect that a lot of our readers do too. As you can in the photo above, I managed to fold over a couple of the fins during the installation process. I’m not exactly sure when that happened as I don’t remember any wrenches falling from the ceiling, but the fact is something unmemorable hit the Mega Fins handguard and dinged it up. Likely, more dings like this are going to show up along the way. All that said, I had zero reliability issues using this handguard whatsoever. But if you expect your gear to get beat up, dusted off, and look factory new, I have my doubts that the Mega Fins will meet your needs.

Specifications: Strike Industries AR Mega Fins / Key-Mod Handguard Rail G2 13.5″ FSP-M

• Weight: 9.3 oz including barrel nut
• Included Parts
  • 1 x Manual
  • 1 x Mega fins handguard rail
  • 1 x Barrel nut
  • 6 x Barrel nut washer
  • 1 x Barrel nut tool
  • 7 x Screws
  • 1 x Allen wrench
• Available Lengths
  • 12”
  • 12.5” FSP-C (carbine)
  • 13”
  • 13.5” FSP-C (mid-length)
  • 15”
• Picatinny Top Rail
• Key Mod from receiver to end in seven positions around circumference
• MSRP: $150 as tested

Ratings (out of five stars):

Overall Quality * * * *
Out of the box, the Mega Fins handguard appears to be made of high quality materials and is sufficiently coated to resist light scuffs and abrasions. After further (ab)use, it showed visible signs of wear especially around the fins which seem to be easily folded and damaged. This never resulted in any structural failures, but does present some cosmetic issues.

Key-Mod Fitment * * * * * 
I used Key-Mod sections from several manufacturers without issue. All of the Key-Mod holes seem to be identical and no matter where I put things, the Key-Mod sections fit

Installation * * * *
Timing things correctly on any free floated handguard takes time and patience. The Mega Fins handguard is no different. Use the correct tools, take your time, and all should be well in your world. The only system that works better in my mind is the Noveske NSR system which just requires you to forget what you read on the internet about torque specs and tighten it until it fits.

Fitment * * *
The unsightly gap between the receiver and handguard is a deal breaker for me. And to be very fair, you might not need to use any shims in your installation, and things will fit together perfectly. All I know is that mine didn’t. Your mileage might vary. Furthermore, it only presents functional issues if you’re using some long section of Picatinny mount that requires you to traverse the area from upper receiver to handguard. That’s a VERY small amount of users myself included, but it is worth consideration. Either way, it doesn’t look “finished” if there’s a gap. I hope that the Gen 3 version of this handguard will resolve that particular issue.

Accuracy Impact * * * * *
This gun was a ~2 MOA shooter before and it is still a 2 MOA shooter now. Changing over to the Mega Fins handguard didn’t seem to affect performance whatsoever. I didn’t imagine it would, but figured it was worth mentioning that I saw neither positive or negative effects.

Overall Rating * * * *
I struggled over knocking a whole star off a four star rating for what are realistically cosmetic issues, and decided against it. My two major gripes, the gap between handguard and receiver and the easy damage done to the fins, never messed with the functional use of my AR. This is still a solid handguard that works very well and possess a great deal of modularity by presenting seven Key Mod sections around the circumference. It also allows you to use the A2 style gas block, or have access to an adjustable gas block which I find to be a great feature advantage. I think if Strike Industries fixes the “gap” problem, they’ve got a very solid, unique product on their hands.