The Magpul STR (Storage/Type Restricted) is a drop-in replacement buttstock for AR15/M4 carbines using commercial-spec sized receiver extension tubes.

A storage-capable version of the CTR®, the STR has improved cheek weld and two water resistant battery tubes on a compact, reinforced polymer A-frame design. A shielded operation lever and supplemental friction locking system prevent accidental operation and minimize excessive stock movement for enhanced weapon stability and accuracy.* The STR incorporates two integral sling loops, a reversible push-button QD sling mount, and a replaceable 0.30" rubber butt-pad which provides positive shoulder purchase to prevent slippage even with body armor or modular gear.

Features:

• Mounts on commercial-spec sized carbine receiver extension tube (not included) from manufacturers such as Bushmaster, DPMS, Olympic, and others (please see the note below)
• Two water-resistant battery storage tubes located on the left and right sides of the stock
  • Each tube will store up to two (2) CR123A lithium or AA batteries
  • Tubes are accessible from the rear in any stock position via a hand-removable rubber plug
• Supplemental friction lock minimizes accuracy robbing wobble*
• Premium chrome-silicon lock spring provides positive locking and long service life
• Sloping cheek weld provides a wide contact surface for user comfort
• Shielded release latch prevents snagging and accidental operation
• Replaceable 0.30" Rubber Butt-Pad offers an anti-slip surface and increases impact protection
• Compatible with Magpul ASAP® and other receiver-mount sling attachments
• Sling Mounts
  • Rear – Reversible Type 1 Sling Mount fits up to 1.5" push-button QD swivels (swivel not included)
  • Rear/Bottom – 1.25" sling loops

Specifications**

• STR, Commercial-Spec (stock configuration)
• Weight: 0.77 lb.
• Weight, w/ Rec. Extension: 1.10 lb.
• Length, Maximum: 7.30 in.
• Width, Maximum: 2.58 in.
• LOP Adjustment Range: 3.80 in.
• LOP, M4 Collapsed: 11.10 in.
• LOP, M4 Extended: 14.90 in.

NOTE: There are two basic sizes of M4 Carbine receiver extensions (buffer tubes): mil-spec and commercial-spec. If you have a mil-spec extension on your rifle, make sure to order the Mag-470 Mil-Spec STR.
 
* Friction lock performance may vary depending on the host receiver extension's dimensional tolerances.
 
** Specifications based on extended-length (slant-back) commercial-spec carbine receiver extension and may vary depending on tube manufacturer. Standard Rubber Butt-Pad, 0.30" or the optional Extended Rubber Butt-Pad, 0.55" and Enhanced Butt-Pad, 0.70" may be used with either Mil-Spec or Commercial-Spec STR stocks.

WARNING: Observe safe firearm handling practices at all times. Failure to do so may result in serious bodily injury or death.
  
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