Looking for something compact, deadly accurate and small in the hand?
Hardened Arms is pleased to bring you our first slim line style SDX
rail. Featuring Keymod attachment points at 3, 6 and 9 with a full
length top rail you will love the new rail style. Matched with our 16"
4150CMV 300blk barrels machined in house this deal won't last long!
Please allow 3-6 week delivery times for this item. Limit 10 per household.
Complete AR15 SDX Upper Receiver Assembly:
Hardened Arms M4 Feed Ramp Flat Top Receiver
Black anodized mil-spec finished upper receiver
Feed ramps for increased feeding reliability on barrel and upper
Laser etched T-Marked upper receiver
4150CMV .300 Blackout High End Barrel
Black Melonited/QPQ Finish
Stress Relieved for superior accuracy
Chambered in .300 Blackout
16" HBAR Profile barrel with M4 Extension
.750" barrel diameter at gas block
5/8x24 threaded muzzle/barrel
Low profile gas block
Barrel dimpled to secure gas block
Pistol length gas system
A2 flash hider
SDX free float rail (no end cap available)
Fits any mil-spec AR15 lower receiver.
Arms uppers are high end, accurate, head spaced, inspected and test
fired prior to shipping. They are built using stringent specs, top
quality parts and procedures to ensure maximum reliability and
You are responsible for knowing your state laws
regarding barrel lengths, pistol, Short barreled rife restrictions. 20%
restocking fees if you can not take delivery due to state restriction.
Dealer programs are available on our website. Two year warranty against
manufacturer defects. Finishes will wear with use, no warranties apply
to finish wear.