AK47 KNS Precision adjustable piston in a PSA-AK GF3

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  • MountieHoo

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    https://www.knsprecisioninc.com/product/ak-adjustable-gas-piston/

    Has anyone installed the KNS adjustable gas piston in a Palmetto State Armory GF3 AK. I've seen varied reports about it working without issue vs. not fitting and needing some gunsmithing.
    The PSA-AK GF3 is technically an AKM variant so for people that have been successful on Facebook it seems they're using the AKM variant of the piston.
     

    IUKalash429

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    If you haven't yet, I'd reach out to PSA customer service and ask them for clear guidance (and if they say "go for it," I'd get that in writing via email in case something goes wrong and you need to send in the AK for warranty work). The Arfcom thread from a few months ago (which PSA, KNS, and others chimed in about with some pretty differing opinions) didn't exactly instill a lot of confidence.

    I have a KNS piston in my Galil ACE and was honestly surprised at just how easy the swap and perfect the fit both were. With all of PSA's AK growing pains (and I'm still rooting for them every day!), any fitting and/or gunsmithing that's required, or gremlins to chase in order to get the piston to work, more than likely means there is something wrong with your gun to begin with. "Precision" is in KNS's name, after all.
     

    SarahG

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    If you haven't yet, I'd reach out to PSA customer service and ask them for clear guidance (and if they say "go for it," I'd get that in writing via email in case something goes wrong and you need to send in the AK for warranty work). The Arfcom thread from a few months ago (which PSA, KNS, and others chimed in about with some pretty differing opinions) didn't exactly instill a lot of confidence.

    I have a KNS piston in my Galil ACE and was honestly surprised at just how easy the swap and perfect the fit both were. With all of PSA's AK growing pains (and I'm still rooting for them every day!), any fitting and/or gunsmithing that's required, or gremlins to chase in order to get the piston to work, more than likely means there is something wrong with your gun to begin with. "Precision" is in KNS's name, after all.
    I was looking at the KNS piston last night and was wondering if it would be worth it. What are your general thoughts? I was hoping for a little recoil reduction as my AK is severely over gassed and chucks brass out into the great beyond.
     

    MountieHoo

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    I was looking at the KNS piston last night and was wondering if it would be worth it. What are your general thoughts? I was hoping for a little recoil reduction as my AK is severely over gassed and chucks brass out into the great beyond.

    What brand is your AK? I’ve seen nothing but glowing reviews from anyone that gets it installed. One reviewer had a mildly tempered positive review because he installed a really good muzzle break on it too right out of the factory and wasn’t sure which one was more responsible for the better recoil impulse


    Sent from my iPad using Tapatalk
     

    SarahG

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    What brand is your AK? I’ve seen nothing but glowing reviews from anyone that gets it installed. One reviewer had a mildly tempered positive review because he installed a really good muzzle break on it too right out of the factory and wasn’t sure which one was more responsible for the better recoil impulse


    Sent from my iPad using Tapatalk
    Arsenal SAM7R - I did a little Google-Fu, but didn't find much about them specifically in that gun. I assume it would function about the same in everything.
     

    MountieHoo

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    Arsenal SAM7R - I did a little Google-Fu, but didn't find much about them specifically in that gun. I assume it would function about the same in everything.
    It looks likes yours would take the Arsenal Large Bore Variant Rifle Variant. Found a thread on AR15 and and a guy said it made a difference especially when running it suppressed
     

    IUKalash429

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    I was looking at the KNS piston last night and was wondering if it would be worth it. What are your general thoughts? I was hoping for a little recoil reduction as my AK is severely over gassed and chucks brass out into the great beyond.

    Sarah, it's a bit pricey but is a solid investment IMO. The ACE might as well be called the spACEx for as far as it spits spent cases. The KNS piston tamed recoil and greatly reduced the distance of said cases. This Galil will serve as a suppressor host, but even if you don't plan to can your SAM I'd still recommend adding the piston. Installation is quite easy!
     

    SarahG

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    Sarah, it's a bit pricey but is a solid investment IMO. The ACE might as well be called the spACEx for as far as it spits spent cases. The KNS piston tamed recoil and greatly reduced the distance of said cases. This Galil will serve as a suppressor host, but even if you don't plan to can your SAM I'd still recommend adding the piston. Installation is quite easy!
    I ordered one this evening. We'll see how it goes!
     

    snorko

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    Appreciate you starting this thread. I will definitely look into this for my Draco and Krink as I hope to shoot both suppressed in the future.
     

    MountieHoo

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    Appreciate you starting this thread. I will definitely look into this for my Draco and Krink as I hope to shoot both suppressed in the future.
    9B256480-90CB-4568-8038-3B0985B99C2E_1_201_a.jpg
    You're welcome. So I finally made the plunge and installed it today on my PSA-GF3 AK (technically AKM pattern). I read in an forum on the AR15 site that a GF3 owner had issues with his install but most did not have issues. This owner stated after installing the KNS piston it would keep hitting the top of gas tube and wouldn't run smooth. PSA took care of it for him after he sent everything in and they shaped it to fit for him. PSA noted that the serialized bolt/piston setup does undergo some fitting in the factory to make it run smooth. Because of that I did not mess with my serialized original, instead I ordered a backup from PSA to mess with (thankfully it was on sale for 1 day last week before going up in price again). In the pic above you'll note I lined up the original on top and the replacement on the bottom. It may be hard to tell but the piston head on the original is at least a good 2mm shorter than the replacement. On closer inspection it looks like the one that came with my rifle had its piston head sanded down somewhat to make it run smooth. I tried putting in the replacement bolt-piston in my AK and it did not run smooth, it felt like it was meeting resistance. I did some searching on the PSA AK owners group and an owner noted when he installed the KNS piston he had to sand down the head to make it fit. So you could imagine I started getting worried when I was meeting resistance with a clean well oiled factory replacement.

    I decided to proceed because when I lined up the replacement piston to the KNS piston the AKM spec KNS piston seemed the appropriate length shorter to make the clearance needed to make the setup run. What I liked was that the threading on the piston was longer proximal to the rivet hole which made it seem to be more stable once I got it in.
    IMG_5230.jpg
    So here's my humble set-up. I don't have a drill press, I don't have a proper stationary shop drill, etc... I did notice in the brownells installation video that the drill bit had a lot of flex when the venerable Mike Papas was drilling out the retaining pin so I had gone to Home Depot and gotten an upgraded drill bit set that was on sale less than 10 bucks. Otherwise I was doing this with a cordless drill, grippy work gloves, and a pistol armorer's block to somewhat hold it in place.
    Unlike the Brownells video my retaining pin was a B*%C# to drill out. In the instructional video it took seconds. It took me the better part of 30 minutes. At first the retaining pin would just laugh at my drill bit. Eventually I got small divots to form on both sides of the pin and I was able to slowly but carefully drill it out. I was not able to tap out the remainder of the pin with a hammer and 1/8" punch until there was a negligible amount of pin left from both sides. I did start with a 1/8" drill bit and down sized the deeper I got on both sides that way I wouldn't enlarge the size of the index holes in the piston-bolt carrier.
    There's a reason specific to the PSA GF3 that that pin was so hard to drill out. When the AKOU did their mostly positive review on the GF3 on their YouTube channel the retaining pin came out somewhere around 3000-4000 rounds and Robski had to use a toothpick to hold the piston to the carrier (successfully) and complete the testing. I believe PSA took it to heart and welded a very thick pin on subsequent productions.
    Anyways, here's the finished product.
    IMG_5232.jpg
    It runs as smooth as the original fitted piston-bolt carrier group in my GF3 during dry fire and racking the bolt several times.
    Will be taking this baby up to Shoot Point Blank this weekend to do the tuning procedure to get it to run on as minimal gas as possible!
    I hope this post will be helpful to someone in the future.
    IMG_5221.jpg
     

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