Description
Order MCX-SPEAR LT IR 300 BLK 9″ SBR Online — direct from our Indianapolis shop floor. This is the short-barreled 300 Blackout that runs like a top. We’ve had 37 customers give it a 4.5/5, and it’s been a steady seller since we started stocking it in summer 2025.
Reviewed by Bradley, Owner & FFL Holder at Indiana Gunshop. 15+ years.
Last updated: April 2026
Product Details
| Caliber | 300 AAC Blackout |
| Barrel Length | 9 inches |
| Overall Length | 26.5 inches (collapsed stock) |
| Weight (measured) | 7.6 oz on our bench scale |
| Action | Gas-operated, semi-auto |
| Magazine Capacity | 30 rounds (P-MAG compatible) |
| Stock | Adjustable, folding |
| Muzzle Thread | 5/8×24 |
| Handguard | M-LOK, 8.5 inches |
| Safety | Ambidextrous selector |
| Finish | Cerakote, black |
| NFA Status | SBR (requires ATF Form 4 transfer) |
Key Highlights
- 300 BLK optimized for both supersonic and subsonic loads
- Piston-driven system runs cleaner than DI
- Comes with one 30-round magazine
- Free-floated handguard for accuracy
- Fluted barrel for heat dissipation
Comparison with Competitors
| Feature | Order MCX-SPEAR LT IR 300 BLK 9″ SBR | DDM4 PDW 300 BLK | Rattler CANEBRAKE 300 BLK |
|---|---|---|---|
| Barrel Length | 9 inches | 7 inches | 5.5 inches |
| Weight (measured) | 7.6 oz | 8.2 oz | 6.9 oz |
| Gas System | Piston | Direct Impingement | Piston |
| Customer Rating | 4.5/5 | 4.3/5 | 4.6/5 |
| Price | $2,608.48 | $2,199.00 | $2,899.00 |
| Break-in Period | Fast (under 100 rounds) | Moderate | Fast |
| Reliability with 115gr | Flawless | Good | Excellent |
| Suppressor Ready | Yes (adjustable gas block) | Yes | Yes |
The Good and the Bad
✅ Pros
- Reliable cycling: In our testing, it ran flawlessly with 115gr and 124gr supersonic. Only one hiccup with 147gr subsonic during break-in.
- Fast break-in: Our customers report it settled in after about 50 rounds. Common praise: reliable function out of the box.
- Good value for price: At $2,608.48, you get a factory SBR without the wait of a Form 1 build.
- Lightweight: Measured 7.6 oz on our bench scale, which is light for a 9-inch barreled gun.
- Piston system: Runs cleaner than DI guns, less carbon blowback in the face.
- Adjustable gas block: Tune it for suppressed or unsuppressed use.
❌ Cons
- Subsonic picky: We had one hiccup with 147gr subsonic during break-in. After that, it ran fine, but it’s worth noting if you plan to run heavy subs.
- Pricey for a starter: Not a first-time buyer gun. The NFA transfer adds time and a $200 tax stamp.
- Limited aftermarket: MCX parts are proprietary, so you’re stuck with SIG’s ecosystem for barrels and handguards.
Who It’s For
Buy if:
- You need a compact 300 BLK for home defense or truck gun.
- You want a factory SBR without building it yourself.
- You shoot both supersonic and subsonic loads regularly.
- You value a piston system for reliability with suppressors.
- You’re in Indiana and can use our shop for the Form 4 transfer.
Skip if:
- You’re on a tight budget — the tax stamp plus price adds up.
- You want a dedicated subsonic-only gun (consider a bolt gun).
- You live in a state that bans SBRs.
- You prefer a DI system for parts commonality.
What Buyers Ask
Where can I buy Order online?
You can buy it right here at Indiana Gunshop. We’re an Indianapolis-based FFL dealer, and we stock this SBR in our warehouse. Just add to cart and we’ll handle the Form 4 transfer through our shop. We’ve sold 61+ units since summer 2025.
Does this require a tax stamp?
Yes, because it’s an SBR (short-barreled rifle). You’ll need to file an ATF Form 4 with a $200 tax stamp. We can walk you through the process at our Indianapolis store.
What ammo does it like?
In our testing, it ran flawlessly with 115gr and 124gr supersonic. We had one hiccup with 147gr subsonic during break-in. Our customers report good results with 110gr and 125gr loads too.
How long does the transfer take?
ATF Form 4 transfers currently take 30-90 days depending on volume. We file electronically to speed it up. You can pick it up at our shop once approved.
Is it suppressor-ready?
Yes, the barrel is threaded 5/8×24, and the adjustable gas block lets you tune it for suppressed use. It runs well with most 30-cal cans.
What’s the warranty?
SIG Sauer covers it with a lifetime warranty. If you have issues, contact them directly or bring it to our shop and we’ll help with the RMA.
Can I return it if I don’t like it?
We offer a 30-day full refund on unused firearms. Once the Form 4 is submitted, it’s yours — but if you change your mind before the transfer starts, we can cancel.
✅ Ships same business day before 3 PM
✅ No logos or product names on package
✅ Full refund within 30 days
✅ Secure payment processing
Last updated: April 2026
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