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AR-15/M16 Enhanced Carbine Length Flat Wire Recoil Spring - Gen 2

Bexar Arms

MSRP: $26.99
Our Price: $23.99
(You save $3.00 )
(23 reviews) Write a Review
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Good enough wasn't good enough, so we're proud to introduce the Gen 2 AR-15/M16 Flat Wire Recoil Spring! Most notably, if you're familiar with the original FWS, the Gen 2 FWS now fits over all buffer styles with no interference.

Round wire springs have been the standard since the inception of the AR-15 in the 1950's. Compared to round wire springs made of music wire, stainless steel, or even chrome silicon, our Enhanced Flat Wire Spring does numerous things better than its round wire counterparts. Our Flat Wire Spring places more load on the bolt when it is in battery which causes bolt lock time time to increase slightly which drops chamber pressures before extraction. It also helps to push the bolt back into battery through adverse conditions and fouling, helps to strip stubborn rounds out of magazines, and can even help reduce bolt bounce. When the bolt is locked open, our Gen 2 Enhanced Flat Wire Spring places the same amount of force on the bolt as traditional round wire springs.

Spring Load in a Carbine Length Buffer Tube:

Bolt Forward in Battery:

Bexar FWS ~ 7.5 lbs
Mil-Spec     ~ 6 - 6.5 lbs

Bolt Locked to Rear:

Bexar FWS ~ 12 lbs
Mil-Spec     ~ 12 - 12.5 lbs

Bring your AR into the 21st century with a Bexar Arms Enhanced Flat Wire Recoil Spring!

The Gen 2 AR-15 Flat Wire Spring is designed and optimized for use in Carbine Length buffer tubes. If you're running an A5 or Rifle Length buffer system, please use our A5/Rifle Spring Spacer in conjunction with our Gen 2 FWS.

100% Made in the USA

A note from Phillip: If your spring still has some rattle or twang once installed, try using some of your favorite automotive grease on the buffer and spring. I personally prefer the full synthetic Lucas X-TRA Heavy Duty "green" type of grease. You'll know if you've used enough when you drop the bolt on an empty chamber and the twang is gone!


  • Gen 2 AR-15/M6 Enhanced Flat Wire Buffer Spring
  • Optimized for Carbine Length Buffer Tubes
  • 17-7 PH Stainless Steel Construction
  • Improved Spring Load Characteristics
  • Reduces Bolt Bounce
  • Reduces Spring Rattle
  • Lifetime Warranty
  • Weighs 2 oz
  • 100% Made in the USA

Recommended Uses:

Use our AR-15 Enhanced Flat Wire Buffer Spring on any gas operated small frame AR calibers such as:

  • .223 Rem/5.56 NATO
  • 6mm ARC
  • 22 Nosler
  • .224 Valkyrie
  • Supersonic 300 Blackout
  • 6.5 Grendel
  • 6.8 SPC
  • 7.62x39
  • 9mm PCC straight blowbacks
  • etc.

DO NOT use with the following:

  • Receiver Extensions shorter than Carbine Length
  • Subsonic 300 Blackout
  • AR-10/SR25 or any Large Frame AR's
  • .308 Win/7.62x51 NATO
  • 6.5 Creedmoor
  • .260 Remington
  • .243 Winchester
  • etc.
While buffer springs are normally a wear item that are replaced in regular service intervals, we are so confident that our Enhanced Flat Wire Springs will never be shot out or damaged from normal shooting that we guarantee it for life! Should you somehow manage to make our Enhanced Flat Wire Buffer Spring fail to do its job, contact us and we will send you a replacement free of charge. Should you try our Flat Wire Spring and decide it's not for you, please contact us for a full refund. We will refund you the cost of the spring, the original shipping charge, AND send you a free return label. Warranty does not apply to any springs that have been permanently modified in any way.

23 Reviews Hide Reviews Show Reviews

  • 5
    Gen 2 Spring

    Posted by Eric D on Jan 28th 2024

    This is a great carbine length spring. Works very well in my AR-9 setup, and it keeps spring noise to a minimum when shooting suppressed.

  • 5
    AR-15/M16 Enhanced Carbine Length Flat Wi

    Posted by Patrick G on Jan 21st 2024

    Fit and works perfectly.

  • 5
    Great Spring For Any Build

    Posted by Sam on Jun 9th 2023

    I have Bexar flat wire springs on most of my AR-15 builds and love them. They function incredibly well on my suppressed SBRs and standard length rifles alike.

  • 5
    Love Bexar Arms

    Posted by Justin Oden on Mar 10th 2023

    Great product, showed up faster then expected, install was a breeze. Even came with some cute stickers!

  • 5
    Enhanced Recoil Spring

    Posted by Eric Laird on Aug 5th 2022

    Outstanding performance..highly recommend this spring!

  • 5
    Great Value

    Posted by Alvin on Jul 24th 2022

    This spring is arguably one of the best bang for you buck upgrades you can do for a traditional carbine length buffer assembly

  • 5
    Gen 2 Flatwire

    Posted by Hamp Willis on May 5th 2022

    Outstanding product at a great price

  • 5
    Flatwire buffer springs (gen2)

    Posted by Nick on Apr 30th 2022

    The best thing about these things for me is the increased load at full extension - even if I'm riding the charging handle the whole way, these things have enough oomph that I've noticed my habit of thumbing the BCG scallop has become entirely pointless. That extra little push at the end seems to help with chambering steel cased rounds after lacquer starts building up too. Only real "disadvantage" these have over cylindrical coil springs is that they squeak noticeably more because of the flat outsides of the springs - but that goes away with a smudge of grease down the length of the spring.

  • 5
    Great Buffer Spring

    Posted by Jonathan H on Apr 7th 2022

    You definitely can feel the difference with this buffer spring, It has more pressure on the bolt but operates the same as a mill spec on recoil, definitely recommend it.

  • 5
    Flat Wire Recoil Springs gen 2

    Posted by Christopher Stratton on Apr 6th 2022

    Flat is Justice UwU

  • 5
    Nice upgrade

    Posted by Zach Dillon on Mar 26th 2022

    This recoil spring will last longer than a round wire spring due to not getting as fully compressed when the bolt travels rearward. For the price, it makes your rifle feel way smoother and nicer.

  • 5
    Buffer spring

    Posted by James Collins on Dec 25th 2021

    Excellent product and service. Repeat customer that will be coming back many more times!