TFB Review: Original SIG Sauer MCX vs Spear LT

Welcome back to another review from The Firearm Blog. Over the past few weeks, I have put up a review of my SIG Sauer Spear LT. If you happened to miss my review on the Spear LT, be sure to click the link here to check it out. With the latest version of the MCX line of rifles, I wanted to look at the original model to see what changes have happened and why the original MCX line of rifles was so popular and continues to be desirable. Let’s take a closer look at the original SIG Sauer MCX vs Spear LT

The Original MCX

Back in 2015, the SIG Sauer MCX was released at SHOT Show and it was one of the most popular AR-15 alternative rifles on the market. It was sold for around $1899.99 which was fairly high priced for mainstream consumers but it really did offer a shorter and lighter platform than most traditional AR-15s at the time. The original variants of the MCX offered a lightweight pencil profile barrel and a KeyMod handguard that was easily interchangeable and swapped out for aftermarket options. Even the full 16” models were incredibly lightweight compared to SIGs ARs at the time or competitors options.

Handguards 

I remember working at a Gander Mountain at the time behind the gun counter wanting one more than anything. The price was the part I struggled with most and at the time I just couldn’t afford one. Fast forward to 2024 and I recently picked up an original 11” MCX and compared to the new Spear LT, there are a number of changes SIG made over time. There are some obvious changes like the switch from the old-school KeyMod style to M-LOK and less known changes like the heavier barrel profile and handguard lockup.

One of the great things about the original MCX as well as the smaller Rattler designs was the ability to quickly switch out the handguards without much effort or disassembling at all. This was really useful when you wanted to use a longer rail that sleeved a suppressor on the shorter Rattler-style firearms but also made it possible to have different setups either for night shooting or regular daytime use for quickly changing over in a hurry. It’s certainly not a necessity but it was a really cool feature that isn’t common on most modern firearms.

Why Are Original MCXs So Desirable?

When looking at just the surface of original MCXs selling for more than they were new, many people in the community start to scratch their heads. The later Virtus rifles had barrels that held up better to hard use and were built to be more robust. For most, the Virtus rifles were a better pick because they were tougher and could be abused with no problem. The main issue with the Virtus was all the durability and beefing up of internals added a fairly noticeable amount of extra weight. The Original MCXs are incredibly desirable because of their lightweight balanced feel in the hands. People would often take some of the barrels from the Virtus while leaving the lightweight handguard making it one of the rare MCX 1.5 Gen rifles which was the greatest hits of both the original MCX and Virtus Rifle.

When the Spear LT came out, they lightened the weight up, especially in the handguard making it feel very similar to the original MCX with the extra durable parts. SIG certainly listened to its customer base as well as its military contracts making a durable yet lightweight option in the MCX platform which is where the Spear LT came from. The handguard design for the Spear LT is more robust compared to the original with physically being screwed into the receiver but the days of quickly swapping out rails for various needs are gone sadly. It’s certainly a loss of modularity but an improvement when it comes to overall reliability when you want a hard-use rifle.

Performance Comparison

When it comes to actually shooting the original MCX and comparing it to the new Spear LT, there are a few differences between the two. The original MCX is slightly lighter than the Spear LT still because of its lightweight barrel and minimalist handguard. One of the benefits of a lightweight option is how fast you can transition between targets with minimal effort since the rifle weighs almost nothing upfront. It can snap between targets extremely fast. The negative aspect is my original 11.5” has the original factory springs still which aren’t as good as the current generation springs. This shows in both felt recoil and overall firing impulses.

The original has a snappier and direct recoil impulse that makes fast succession shots tricky to land on target whereas the Spear LT is a flatter shooting rifle even without a muzzle brake or any other assistance. Both rifles use factory muzzles and springs which makes comparing them an even playing field. The trigger on the Spear LT is lighter with a crisp reset and just feels like a match trigger whereas the original MCX feels like a mil-spec style trigger that has been polished. The Spear LT has a better trigger in my opinion but both are usable, to say the least. If I had to pick between the Virtus line of files or an original MCX, I would choose the original MCX 100% of the time since it’s drastically lighter than the second generation and so far the original has proven to be a reliable accurate firearm.

Suppressor Options

When it comes to suppressor options for the Spear LT, I went with the HUXWRX FLOW556K suppressor and the SIG SLX line of cans to keep the rifle lightweight and have the added bonus of less gas. The original MCX would certainly benefit from a muzzle brake to kill any of the excess movement due to the older spring design. For those I would probably recommend one of the companies with fantastic muzzle brake options and there are a few favorites of mine personally so let’s check it out.

SilencerCo Velos LBP 556K

The SilencerCo Velos LBP 556K is an updated version of the Saker K suppressor and takes the same ASR muzzle devices as other SilencerCo models. The SilencerCo ASR lockup is a solid lockup and one of the most popular on the market in terms of muzzles and design. Several companies make aftermarket muzzles for the ASR platform which only helps people change out muzzles like the one for the MCX. The Velos 556K is a compact device that is perfect for the shorter 11.5” package while offering a decrease in overall decibels making it safe to fire without ear protection. With a shorter SBR having a shorter overall package suppressed is a huge plus and the Velos offers a compact package while having an impressive amount of noise reduction.

Silencer Shop makes getting suppressors easy and you can buy the SilencerCo Velos LBP 556K suppressor from the link below.

SureFire Socom 556 RC3

When it comes to reliability and a fantastic lockup, it’s hard not to talk about the SureFire line of suppressors. The SureFire RC3 is the newest variant of the ultra-reliable RC line of suppressors. I have an RC2 that I have used for years with absolutely no issues. If I had to say what my favorite lock-up system was on any suppressor, it would probably be what Surefire does on their suppressors. The RC3 is also one of the shorter options as well making it perfect for shorter compact rifles like the 11.5” MCX. Another positive of the RC3 is the fact it runs on the Socom line of muzzles and the Socom muzzle brake is one of my favorite muzzles out there for its simplicity and overall look on a rifle. Silencer Shop also carries this can which you can buy here:

Overall Thoughts 

Now if I had to pick between the Spear LT and the original, that’s a much harder decision. I think with the new handguard shape as well as the robust lockup, I would end up picking the Spear LT for its upgraded barrel and overall balance of weight and performance. The original is a fantastic option and if you like them as a collecting piece or AR alternative, it’s a great option no doubt. If you’re starting out and looking for an MCX in general though, I would probably start with the Spear LT over everything because it’s the successor to the overbuilt Virtus but has similar lightweight properties to the original making it the best of both worlds.

What do you guys think about the MCX line of rifles? Do you prefer the older models, Virtus rifles, or the newer Spear LT line? Let me know what your thoughts are down in the comments below. If you happen to have questions bout the MCX or Firearms in general, feel free to shoot me a message on Instagram @fridgeopeartor. Stay safe out there and we will see you in the next review.