Strike Industries AR Carbine Flat Wire Spring

Manufactured by Strike Industries
Manufactured by Strike Industries
10 Reviews

In Stock

Standard orders will ship out the same business day if ordered by 3:30 pm CST. FFL orders will ship within 5 business days or less as long as we have the information for the transfer destination.



Strike Industries products are designed by shooting experts for the shooting sportsman.

The Strike Industries Flat Wire Carbine Spring is an inexpensive and easy upgrade for your AR-15. Designed to smooth recoil, this spring produces an increased bolt load yet requires less compression force improving reliability in cycling.

SI Flat Wire Springs are made from cryogenically stress relieved 17-7 PH steel to provide greater consistency, longer spring life, and increased resilience to high cyclic rates.


  • Cryo-cycled 17-7 PH steel
  • Decreased harmonics lessens system vibration for faster follow up shots.
  • Increased bolt load
  • Reduces distracting AR twang
  • Outside diameter: 0.94"
  • Inside diameter: 0.75"
  • Length: 13 7/8"
  • Gauge (Flat Wire Profile): 0.045" x 0.0935"
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BrandStrike Industries
MaterialSteel - 17-4 PH Stainless
TypeAction Spring - Carbine Length

WARNING: This Product can expose you to chemicals which is known to state of California to cause Cancer and Reproductive Harm. For more information, see

Too Much Noise And Drag From Flat Wire Extra Surface Contact


I'll give this item 2 Stars for being pretty but I wouldn't give you 2 bucks for it.<br><br>There was nothing wrong with my stock spring but I thought this might be better. Nope.<br><br>My stock carbine spring was smooth and went "ssshhhhhh" when charging. This one goes "SWOOOSSHHHH" and has noticeable drag.Here's why. The stock round spring only contacts the tube with a small surface on the edge of a circle. The flat wire spring contacts the tube with the entire thickness of the flat wire.That's a lot more surface area.<br><br>I replaced this with a JP Polished Extra Power spring and there is a world of difference. Now there is a subdued "shhh" when being charged and the cycle is glass smooth and lighter even with a stronger spring. Very noticeable.<br><br>5 Stars to JP and, as usual, 5 Stars to Primary Arms.

Flawless after 1 year and thousands of rounds.

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I've had this spring in a 11.5 build for about a year now and it has been flawless. I'm not sure why the other review says its louder and has more drag than a round spring because it definitely doesnt. In fact it's about the same with the added benefits of a flat wire spring. Look them up. The loudness has a lot to do with the inside surface of cheapert buffer tubes. If your looking for quite, look for the JP silent captured spring!! It makes the AR action feel very high quality!

Flat spring in Carbine - short stroke.

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I put this flat style spring into a carbine length gas system build on a 16in barrel. Notice that this carbine flat style spring length is 13.5in. (Typical carbine length springs are 11.5 max and rifle length are 13.5in.) This flat spring in my carbine system caused the rifle to short cycle. The rifle would load and fire the first round, but wouldnt travel far enough back to cycle the next round in. I've gone back to the 11.5in standard spring and no issues. Possibly could have gone to a heaver buffer but didnt want to mess with this any further. In my opinion, this spring is too long and also too strong for carbine gas system stroke and travel.

This spring will reduce felt recoil by at least 15 percent.

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I only buy this spring now for all my builds. So to me the magic of this spring is the reduction in felt recoil over a standard mil spec buffer spring. There is no real difference in noise or anything like that but you will without a doubt notice the recoil being positively affected. It is slightly longer than a standard spring but it compresses differently and more easily than a standard spring does. The buffer fits very snugly into the wire as well. Sometimes these are hard to find in stock but are worth every penny as a upgrade for you rifle.

Great upgrade

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Have one in every AR i have

didn't work for me

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Using a 10.3" HBAR with a MK18 spec gas port and a Noveske KX5 with an M16 cut bolt. This spring caused short strokes with anything but full power 5.56, and caused occasional failures to lock back on an empty magazine with 5.56. Compared to a regular spring, this one is a few inches longer, more like rifle length. It's just too powerful for the system I'm running.

Best spring available


Most all my AR platform rifles have one of these flatwire springs and at this price I'll be ordering a bunch more just to have around. These springs are great and most times the need for a heavier buffer isn't needed. These do really well in suppressed rifles and pistols. If you tend to use junk (Russian) or weak (.223) ammo then stick with a standard spring. Using LCA or Federal 5.56 amm I have never had a single issue with these springs and I have a lot of them in every cartridge available in an AR platform. These are a must with guys running ultralite BCG's or full auto LE guns.

No *TWANG* anymore!


I bought this at a local, big store retailer, I love it. I haven’t put any rounds through it yet, but I know it’s truly great. No TWANGGGGG noise AT ALL when closing the bolt now!!! A slight bit more drag noise when charging it, but that doesn’t matter at all to me. The inside of the buffer tube is anodized, it will be fine. One issue though, it is VERY difficult to get around the weighted buffer. I put it on a normal, brand new buffer, it was quite difficult to put on. So make sure you have some GOOD, needle nose pliers, and get the flat of the top of the spring, good and flush against the surface. Excited to take it to the range! I bought mine for $17.99 I believe.

Works Nice


Using this and a standard carbine buffer on a 10.5 my shells eject around 5 o’clock. Doesn’t make too much noise when charging the bolt. Will probably upgrade all my springs to this one.

Very powerful spring


I've purchased this spring from a different retailer but after reading the reviews I feel inclined to add my quick 2 cents. This spring may not work in your setup. I'm running this on my 12.5" 308 with a 3.8 oz buffer and it reduced felt recoil while still cycling fine. I wouldn't recommend for 5.56 builds unless you're experiencing quite a bit of recoil and parts wear. AND LASTLY. Stop complaining about the buffer noise. Nowhere does it state this spring will change the sound. Grease your parts like a normal person or buy a silent capture!