If there is an empty spot in your collection for a very quiet gun with rifle-level knock-down power, this Suppressed 300 Blackout Sig Sauer Spear LT SBR setup is the recipe for you.
Purpose
Can you think of a time when you might want to shoot a rifle without having to wear hearing protection? The reason for building a 300 blackout rifle is to make it quiet without sacrificing knock-down power. Many .223/5.56 rifles are great for a number of reasons, but you cant realistically make a .223/5.56 bullet travel slow enough to make it subsonic. Subsonic ammunition is designed so that it never travels fast enough to create the audible "crack" that happens when a supersonic bullet leaves the barrel at speeds that break the sound barrier.
So our recipe criteria for this one is as follows:
- Compact
- Very quiet
- Rifle caliber knock-down power
- Reliability when suppressed
Why this one?
The Sig Sauer Spear LT checks a lot of checkboxes for a build like this. It comes with a 9" barrel, and provisions to add a folding stock. So the "Compact" criteria is easily met. It is chambered in 300 Blackout, which is available in subsonic variations that allow it to be quiet through a suppressor without sacrificing knock-down power. It comes with an adjustable gas block that lets you dial the gas back for reliable cycling while shooting subsonic ammo while suppressed. The ambidextrous bolt slide catch and release, and ambidextrous mag release are nice features that you'll miss if you pick up another gun without them after getting used to having them on this one.
Suppressor
The Sig Sauer SLH300TI-QD suppressor was designed for this specific application to be as quiet as possible without sacrificing reliability or durability. Physically it is the longest of the SLH suppressors from Sig, but is surprisingly lightweight for its size because it is made out of Titanium.
It comes with a clutch locking quick disconnect collar that mates to the muzzle device that comes on the Spear LT from Sig.
Sig did a really good job of alinging the muzzle device with the hand guard so there is a minimal gap between the hand guard and the suppressor when installed. It looks great, and it wastes almost no space.
Sig does make shorter "30 cal" suppressors that will work on this gun if the guns overall length needs to be shorter for some constraint. But when the conditions allow for it, we prefer this suppressor for 300 Blackout.
Optics
300 Blackout (especially subsonic) is a round that is not designed to travel long distances. For example, a 220gr subsonic 300 backout round could drop more than 100 inches by the time it travels 300 yards. But subsonic sound reduction through a suppressor is the primary reason for building a 300 blackout setup. Because we wont be focused on long distance shots with this round, we typically rule out most magnified optics combos for 300 blackout build recipes unless needed for some other specific requirement.
The EOTECH EXPS3-0 is a staple in the 1x rifle optic line up. It's robust body allows it to take a beating without breaking, and the glass allows for a generous sight picture.
But it's also easy to use. The 68 moa circle dot reticle allows for the shooter to correct for up close hold-over distances by using the bottom of the circle as thair point of impact for very close shots within 7-10 yards, the center dot for shots between 50-100 yards, and the space between them for everything in between.
We prefer the Unity Tactical optic riser for these guns to get the optic raised to a comfortable level that doesnt make us rotate our neck forward and our head down to where we are looking through the top of our eye protection, or have to move the stock way up above our collar bone to line up the reticle on target.
Stock
The 9" .300 Blackout Spear LT is compact enough to easily be concealed or stowed in compact packaging. For this reason we prefer to use a slim, minimlistic, stock like the JMAC Skeletonized Folding Stock. It hugs the gun close when folded, adding minimal thickness to the space it takes up in a bag or compartment.
The rubberized pad on the back is comfortable enough that you won't be thinking about the way the gun feels in your shoulder.
It comes in 2 different lengths, 8" or 9", so you can get the most comfortable length of pull for your specific body type. For reference I am 6'1" tall and the 8" stock feels too short, and the 9" feels perfect to me.
I also like that it comes with QD sling sockets at the back and front of the stock.
It also comes in black if you are looking to do a different color scheme.
Light & Rail
A weapon light is something you wont truely appreciate until you find yourself holding a gun in the dark and not being able to see. That feeling will make you put a light on every gun you own. The M340C is a compact single battery light from Surefire that outputs 500 lumens.
These models come with an M-LOK swivel mount that allows you to rotate the light against the hand guard, where it takes up the least outward space on the gun making it easier to point the gun through openings in cover and reducing snag opportunities.
We also use a dual function pressure switch from Surefire that allows for constant on/off as well as momentary on while pressed and held. This allows for momentary use of the light only when needed, by pressing with your thumb on top of the rail in a natural c-clamp position.
The Arisaka finger indexer helps improve consistency of form by acting as a reference point for c-clamp shooters to grab the gun the same way every time.
Controls
The factory charging handle that comes on the 9" 300 Blackout spear has fairly small tabs on the side. They work, but if you are used to larger tabs, they will feel too small. We prefer the Radian Raptor LT charging handle designed for the MCX because it's impossible to miss, even after fumbling a reload under pressure.
The Radian Talon safety selector switch feels better in the hand than the factory one, and it comes in Tan! It also has the ability to be installed with a 45 degree throw instead of the traditional full 90 degree throw, requiring less input from your finger. This adds up and becomes noticeable when you are clicking to safe every time you move.
Lastly, if you are looking for a lighter trigger, we prefer the Timney DH3 trigger that comes in the Sig M400 DH3. It has a light break out of the box, but it is also adjustable so you can fine tune it to your preference. We love this trigger for fast shooting of multiple shots on target at the same time. Warning, this is a very light trigger, and very light triggers are not right for everyone.
JMAC Customs
SKU: SS-9RP-T+FM-SM-1913
JMAC Customs
SKU: SS-8RP-T+FM-SM-1913
