Lower Parts Kit for AR-15

From complete kits to individual pieces, AT3 has the lower parts you need to build your ultimate AR-15.

We provide high-quality lower receiver parts kit, safety selector, and mag release.

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(532)

AT3™ FU-BAG™ AR-15 Lost Parts Kit – Springs, Detents, Replacement Components
2 Options
from $8.49
from $7.22
Out of Stock
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AT3 Tactical Castle Nut for AR15
(102)

AT3™ Castle Nut for AR-15 Buffer Tubes – 9 Colors Available
9 Options
from $4.49
from $3.82
Out of Stock
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Sale!
(41)

AT3™ MOTHERFU-BAG™ – The BIG AR-15 Lost Parts Kit – Springs, Detents, Wear Parts, and More
$21.49
Only
$18.27
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Pivot Pin/Takedown Pin Detent Springs - 2 Pcs
(42)

AT3™ Mil-Spec AR-15 Pivot Pin/Takedown Pin Detent Springs – Set of 2
$1.39
Only
$1.18
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Buffer Retainer Spring
(16)

AT3™ Mil-Spec AR-15 Buffer Retainer Spring
$1.19
Only
$1.01
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Selector Detent
(5)

AT3™ Mil-Spec AR-15 Selector Detent
$1.19
Only
$1.01
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Selector Detent Spring
(3)

AT3™ Mil-Spec AR-15 Replacement Safety Selector Detent/Ejector Spring
$1.19
Only
$1.01
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Bolt Catch Plunger
(10)

AT3™ Mil-Spec AR-15 Bolt Catch Plunger
$1.69
Only
$1.44
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Bolt Catch Spring
(5)

AT3™ Mil-Spec AR-15 Bolt Catch Spring
$1.19
Only
$1.01
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Buffer Retainer
(9)

AT3™ Mil-Spec AR-15 Buffer Retainer
$2.49
Only
$2.12
Out of Stock
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Sale!
AT3 Tactical Pistol Grip Screw for AR-15
(9)

AT3™ Mil-Spec AR-15 Pistol Grip Screw
$1.19
Only
$1.01
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Pistol Grip Lock Washer
(7)

AT3™ Mil-Spec AR-15 Pistol Grip Lock Washer
$1.19
Only
$1.01
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Magazine Catch Spring
(5)

AT3™ Mil-Spec AR-15 Magazine Catch Spring
$1.19
Only
$1.01
Out of Stock
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Sale!
AT3 Bolt Catch Roll Pin
(2)

AT3™ Mil-Spec AR-15 Bolt Catch Pin
$1.19
Only
$1.01
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Disconnector Spring
(8)

AT3™ Mil-Spec AR-15 Disconnector Spring
$1.19
Only
$1.01
Out of Stock
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DAILY DEAL
CMMG ZEROED Ambi Mag Catch and Button Kit for AR-15

CMMG ZEROED Ambi Mag Catch and Button Kit for AR-15

Save 5%

$46.99
Only
$44.64
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Trigger Guard Roll Pin
(2)

AT3™ Mil-Spec AR-15 Trigger Guard Roll Pin
$1.19
Only
$1.01
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Hammer/Trigger Pins – 2 Pcs
(8)

AT3™ Mil-Spec AR-15 Hammer/Trigger Pins – 2 Pcs
$3.99
Only
$3.39
Out of Stock
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Sale!
AT3™ Enhanced Mil-Spec AR-15 Hammer
(8)

AT3™ Enhanced Mil-Spec AR-15 Hammer
$24.99
Only
$21.24
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Disconnector
(7)

AT3™ Mil-Spec AR-15 Disconnector
$5.49
Only
$4.67
Out of Stock
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Sale!
AT3™ Enhanced Mil-Spec AR-15 Trigger
(2)

AT3™ Enhanced Mil-Spec AR-15 Trigger
$24.99
Only
$21.24
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Hammer Spring
(2)

AT3™ Mil-Spec AR-15 Hammer Spring
$3.49
Only
$2.97
Out of Stock
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Sale!
AT3™ Mil-Spec AR-15 Trigger Spring
(3)

AT3™ Mil-Spec AR-15 Trigger Spring
$2.99
Only
$2.54
Out of Stock
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RECOMMENDED
(121)

AT3™ Pro-Builder™ AR-15 Lower Parts Kit – No Grip or Trigger Assembly
9 Options
from $29.99
from $25.49
Out of Stock
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