Flint River Armory Introdues Their New Gen2 CSA45 Gas-Piston .45 ACP Carbine

Flint River Armory: Gen2 CSA45 Gas-Piston .45 ACP Carbine

The CSA45 isn’t new to Flint River Armory, but their Gen2 version brings a couple of very welcome changes. Gone are the proprietary magazine and the unique receiver extension with matching stock. Replacing them are, as you’d hope, GLOCK mags and AR buffer tube compatibility. Plus KeyMod has been rightly ditched in favor of M-LOK.

Flint River Armory Gen2 CSA45 Gas-Piston .45 ACP Carbine

While dumping the proprietary components makes the CSA45 less unique, in this case that’s a good thing. Plus, the gun is still unique in the market with its rotating, locking bolt and gas-piston operating system. It’s similar to how the SIG MPX operates, but the CSA45 is chambered in the venerable .45 ACP.

Rumor has it that Flint River Armory will be releasing more calibers soon, too. Including 10mm Auto, which is sure to be popular.

In the following video, Flint River’s Founder and CEO walked us through the features of the Gen2 CSA45 at the NASGW show:

Flint River Armory: Gen2 CSA45 Gas-Piston .45 ACP Carbine

Flint River Armory Gen2 CSA45 Gas-Piston .45 ACP Carbine


  1. avatar little horn says:

    :eye roll:

  2. avatar DrewR says:

    U G L Y, this ain’t got no alibi, it’s ugly!

    1. avatar Eric in Oregon says:

      Good grief, no kidding. That thing hit ALL the branches when it fell out of the ugly tree.

      I bet it shoots great though.

  3. avatar PROUD chicano says:


  4. avatar BLoving says:

    When I hear “.45 carbine”, my mind thinks of nothing but the Marlin Camp Carbine.
    If those accountants who’ve never squeezed a trigger in their lives that run Remington today want to save the Marlin brand, I recommend they bring that rifle back. Both in original wood stock and a tacticool flavored version to keep these new kids happy. 🤠

    1. avatar Rokurota says:

      Yes! Can Ruger bring back the PC, too?

  5. avatar Joe R. says:

    Heard “Piston” thought – I like your story, continue. . .

    Saw pic : /

    Were they shooting for trying to look like a Hi-Point carbine in FDE???

    Is that the way to make $$$ on a concept? Put out the performance people are looking for in a package that they’re bound to modify (a lot)?

  6. avatar FedUp says:

    Laser beams will shoot out of them in the next Star Wars movie.

  7. avatar astigmatizm says:

    Put M-Lok on a pig and it’s still a pig. And why they hate’n on Keymod? My MPX has Keymod and I love it.

    1. avatar Remmi300blk says:

      KeyMod is Zoon. M-LOK is the iPod.

      1. avatar Stereodude says:


        1. avatar astigmatizm says:

          You either have to watch “Big Bang Theory” or be over the age of 40 to know Zune? Zune is as old as the I-pod shuffle.
          I still love my Keymod.

    2. avatar sound awake says:

      my local ace hardware sells the same set up as keymod except its for putting up shelving in your garage

    3. avatar sound awake says:

      “MLOK is better. We can say it with conviction now that NSWC-Crane has released a slideshow that details the processes they used to conduct the testing and the results of said testing.

      With no appreciable difference in cost to the consumer and MLOK being theoretically cheaper to produce, there is literally no reason for KeyMod to continue to be offered by top-tier manufacturers. Sure the open source nature of KeyMod is attractive, but getting the OK to build MLOK parts isn’t tough, and the benefits to the consumer appear to be well worth it.”


        1. avatar Eric in Oregon says:

          Just register, there’s no infringement there.

  8. avatar Philthegardner says:

    Come out with a 9″ bbl pistol and you have my attention. The 16″ with a .45 doesn’t rock my jollies. 10mm though…

    1. avatar Jeremy S. says:

      They’ve been making a pistol version of the Gen1, so I’m confident they’ll be releasing one in the Gen2 as well. They also do a factory SBR, which is nice.

  9. avatar sound awake says:

    i wouldnt ever buy a 16″ rifle chambered in .45 acp for the same reason i wouldnt ever buy a 5″ pistol chambered in 5.56…

    plus it’s $1500+

    i could buy a decent 1911 and build a nice ar-15 for that much $

    no thanks…not interested

  10. avatar Joe R. says:

    Front of the fwd handguard seems ~ fragile?

    Range report imminent?

  11. avatar ai338 says:

    Rmw still has the best .45 ar on the market.

  12. avatar Cucamonga Jeff says:

    To complex for a .45ACP. A simple blow back design would get the job done. No need for all the extra parts. Good grief is it ugly….

  13. avatar Aaron says:

    $1500 for a .45 carbine….why? just why? You can get a S&W M&P Sport II AR in 5.56 AND a Colt 1991 version of the 1911 for about $1500.

    I have a MechTec .45 carbine hooked up with the lower from an old Norinco 1911, and I thought that was expensive at about $700.

  14. avatar Lhstr says:

    Man what a beauty, I would look good with it being mine. What are the shooting specs.

  15. avatar Desert Dave says:

    Looks like a perfect Boat Gun! It doesn’t float does it?

  16. avatar adverse5 says:

    Is there a carbine under all that junk?

  17. avatar Greg says:

    OuchUgly! Mechanically intriguing to be sure. Make magwell smaller to fit magazines…wait…just make it look like the LWRC smg45 unicorn…and I and I’m sure a lot of other people would gladly give up their money for the 45, 9, 10mm versions. We want to shoot something reliable, good looking and, did I say reliable? Do this and we”ll be your customers!!!


    Customers who just told you how to get us to be your customers

  18. avatar ELIAS VARAS says:


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