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BOLT M4 B-4 Knights Armament SR-16 URX 3.1 Full Metal Recoil EBB Airsoft AEG Rifle (Color: Tan)

ID: 51531 (AEG-B4SR16URX3-R-120T)
5.0 stars, based on 2 reviews
BOLT M4 B-4 Knights Armament SR-16 URX 3.1 Full Metal Recoil EBB Airsoft AEG Rifle (Color: Tan)
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Optic shown in images not included.


This item is currently Out of Stock Usually restocked within 1-3 weeks.
Add to your wishlist to stay posted!

MAP ProtectedExempt From Coupons
The manufacturer of this product enforces a strict minimum advertised price (MAP) policy which excludes this product from any additional discount coupon codes. This item, however, may qualify for free shipping.
CanadaExport Compliant
This gun has a muzzle velocity rating (FPS) between 366 and 500, and is compliant for export to Canada.

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Color Options:
Optic shown in images not included.BOLT Airsoft brings the realism of recoil feedback to the AEG market through their patent pending Bolt Recoil Shock System (BRSS for short). The BRSS design provides an extremely authentic kick providing the user with extremely realistic feedback. The BRSS design rivals many Gas Blowback rifles currently available.


  • Realistic recoil feedback from the patent pending BRSS system
  • Modular URX 3.1 front end for tactical accessories
  • Golf ball textured handguard panels included
  • Full metal receiver and barrel assembly
  • Licensed Knights Armament laser engraved trademarks
  • Flat top Picatinny rail for optics
  • Ambidextrous magazine release
  • Detachable front and rear flip up sights
  • Retractable crane stock
  • Mock bolt with realistic blowback
  • Compatible with standard Ver.2 parts
  • Reinforced gearbox with heavy duty internal parts
  • CNC stainless steel spur gear
  • CNC aluminum piston set (w/ full steel tooth)
  • High torque motor
  • Aluminum alloy 6.01mm tightbore inner barrel
Length: 805mm-890mm, Adjustable
Weight: 2780g
Inner Barrel: 363mm
Magazine Capacity: 300rd Hi-Capacity. Works with Matrix, G&G, Tokyo Marui and other compatible M4 / M16 Series Airsoft AEG Magazines
Muzzle Velocity: 380~400 FPS (Measured with 0.20g BBs)
Thread Direction: 14mm Negative
Gearbox: Ver 2 Full Metal, Fully Upgradeable
Motor: Long Type
Fire Modes: Semi/Full-Auto, Safety
Battery: 9.6v Small Butterfly Type or similar sized LiPoly recommended (Battery not included. Wired to the rear with a Small Tamiya Connector)
Hopup: Yes, Adjustable
Package Includes: Gun, Magazine, Manual

Manufacturer: BOLT

Things you may need to get started:
    Battery and Charger – Required to power your AEG; use a high quality battery and charger for best results.

    Spare Magazines – Stay in the fight longer by bringing more ammo with you.

    BBs – High quality precision 6mm BBs recommended; Use 0.20g – 0.25g BBs for best results.

    Silicone Oil – Basic cleaning and lubrication maintenance help keep your Airsoft AEG in top working order.

FPS Range: 380-400

California residents click here for Proposition 65 warning

2 Customer Reviews

(Write a review)

by Ryan M. on 12/29/2017
"Iíve had this gun for about a few months now and absolutely love it. Currently Iím doing some upgrades to make it that much better such as a new tightbore barrell cnc hop up new bucking spring all the good stuff. Only 1 thing the battery is kinda tight to fit a 9.6v butterfly would defiantly recommend a 7.4v lipo only because of the space and wire could get cut. But overall great product!
by Peter T. on 05/05/2015
"I have had this for a couple of months now and am quite pleased with it,
There are a couple of items that could be better, battery life is only a few hundred rounds so carry a spare if you are going war gaming with this, better make it two spares.
Also the battery is a tight fit, getting all the wires tucked away can be a bit of a challenge, doable but not easy.
The trigger on mine is a bit touchy in the semi position and locks up if you are not precise in your follow through, seems fine in auto.
All in all though I am quite happy, it recoils harder than a .22 version of an AR and I feel that it makes an even better trainer for this reason.

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This item is currently Out of Stock. Most out of stock items are restocked within 1-3 weeks. Some items may take longer. Please add this item to your wishlist to keep posted on its availability.

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