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Posted: 2/22/2013 7:17:05 PM EDT
| the piston rod on my AA kit is binding on the barrel nut and or handguard spring. when i take the piston out of the block, the rod will be on a slight incline towards the end of the barrel. when its on its own like that, it moves freely back and forth. but when the rod is attatched to the piston and in the block, you cant move the pushrod manually. i tried to drill out around the barrel nut and handguard spring to open it up but not sure if that helped out at all. any ideas? |
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You need that rod to move so freely that gravity will slide it with no spring in place. Do all your testing with the spring and bushing removed.
I had to have a machinist mill a shallow groove right in to my OEM barrel nut. It was not so much that anything was weakened or compromised. At the same time, he had to WIDEN the space between the barrel nut teeth/lugs where the piston rod passed. Then grease this area with a high moly content grease or WA25t grease. The BEST bet would be to coat the area and rod with a permanent dry film coating like cerakote Micro Slick and then add your grease. I am doing exactly that to my AA kit. You need to fuss with the ALIGNMENT of the gas block and actual position of the barrel nut too. You may need to SLIGHTLY tighten or loosen your barrel nut. To CHECK to see if your barrel nut is in the perfect spot, swing your piston rod from side to side when it is removed from the gas block. it should swing both ways exactly the same amount. All these liitle fine adjustments are absolutely critical for the successful operation of your AA system over thousands and thousands of cycles. Any questions? Final check: remove BCG. Remove piston spring and bushing. connect piston to gas block. The piston should travel its full stroke with ZERO binding. TWIRL your PISTON ROD WHILE CHECKING SINCE they are often not 100% perfectly straight. No problem. a tiny tiny bend is OK as long as there is NO binding when you swirl your piston rod 360 degrees.while checking its STROKE. Capishe? I had to have a nice sized groove machined in my barrel nut until I was completely bind free!!! I can see and my machinist assured me that the barrel nut in NO way was weakened to the point that it would ever think of failing in any way. the groove is still only a tiny fraction of of the over all thickness of the nut. I am a worry wart. But not about this item. Especially now that the rod moves so freely! |
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It's possible the piston is bent.
Mine was and I read on here that a couple others were as well. I emailed Jacob @ Adams Arms and he said he would send out a replacement but I haven't received it yet. (10 days ago) Since it's "staged" sometimes it's hard to do the roll test. But let the "cup" part hang off an edge and roll the piston on the thicker part. If it is bent you should see the skinnier end wobble up and down a little bit. That's how mine rolled. It could get stuck on the barrel nut in certain positions. |
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my first rod was pretty bent. I ended up getting TWO spare rods sent over a period of time when my set up was on a Carbine length barrel (now its mid). Even the brand new replacement short carbine rods I found were not 100% spot on perfectly straight. Two of mine CAME with SLIGHT bends which you can feel when you twirl the rod. I had my barrel nut metal relieved to accommodate the almost un noticeable bend. The gun functions flawlessly and the bend stays exactly the same which is "barely there".
I really would be hesitant to order a replacement unless you see or feel a significant bend. its just so easy to deal with a slightly out of spec rod and have the gun function perfectly for years after. My kit is two years old. I got one of the very first LITE carbine kits. Depending on your barrel nut manufacturer I think that SOME will just need slight mods to prevent binding no matter how straight your rod is. You can always try a different brand barrel nut. They are not expensive. I could have tried that. instead I just had the nut clearance modified so it would not bind on the rod. problem solved. No guarantees that the nut you buy will work. But it may be a better option for you personally. I didnt care. I just wanted mine to work, guaranteed. The method I chose met that. |
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Quoted:
my first rod was pretty bent. I ended up getting TWO spare rods sent over a period of time when my set up was on a Carbine length barrel (now its mid). Even the brand new replacement short carbine rods I found were not 100% spot on perfectly straight. Two of mine CAME with SLIGHT bends which you can feel when you twirl the rod. I had my barrel nut metal relieved to accommodate the almost un noticeable bend. The gun functions flawlessly and the bend stays exactly the same which is "barely there". I really would be hesitant to order a replacement unless you see or feel a significant bend. its just so easy to deal with a slightly out of spec rod and have the gun function perfectly for years after. My kit is two years old. I got one of the very first LITE carbine kits. Depending on your barrel nut manufacturer I think that SOME will just need slight mods to prevent binding no matter how straight your rod is. You can always try a different brand barrel nut. They are not expensive. I could have tried that. instead I just had the nut clearance modified so it would not bind on the rod. problem solved. No guarantees that the nut you buy will work. But it may be a better option for you personally. I didnt care. I just wanted mine to work, guaranteed. The method I chose met that. Well I'm going to have to agree with you. I just got the replacement rod and it has a slight bend in it causing some minor binding also. Oh well, I guess I'll give it a try. At least I have a spare now. 
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So... You got the retro kit with a bent rod?
It's always good to have a spare, you never know when it might break http://i604.photobucket.com/albums/tt122/Jnv255/c7efe4e5.jpg http://i604.photobucket.com/albums/tt122/Jnv255/087c5067.jpg Had nothing but problems with the retro kit. Adams ended up giving me a complete upper free of charge after getting the run around. The upper has been fine, but that retro kit is for the birds.. |
Don't just focus on the problems also look at the customer service. This guy got a bad deal on a retro kit and got a full upper. In my book thats what makes me deal with companys like this. Adams Arms is good with me, I'm looking into getting anothe 625. lite kit when they become available. 
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Quoted:
So... You got the retro kit with a bent rod? It's always good to have a spare, you never know when it might break http://i604.photobucket.com/albums/tt122/Jnv255/c7efe4e5.jpg http://i604.photobucket.com/albums/tt122/Jnv255/087c5067.jpg Had nothing but problems with the retro kit. Adams ended up giving me a complete upper free of charge after getting the run around. The upper has been fine, but that retro kit is for the birds.. Doesnt the AA upper use the same piston parts as the retro kit ? The only difference being : 1. Your barrel and upper 2. Their barrel and upper 3. They installed their piston parts on their barrel and upper. 4. You installed their piston parts on your barrel and upper. Maybe you screwed up the installation ? Maybe your parts had problems ? Maybe the retro kit you got was bad ? What were the problems with your retro kit build ? |
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I have 4 Adams arms kits, all but one is installed. I had two problems....one was my fault. When installing the cup into the upper reciever, I went a little too far, and the cup deformed just a bit. A small dill bit, and it was fixed. The other problem was a bent op rod. I posted here, and was immediately contacted by Adams Arms before I even sent an email for an RMA. As soon as an op rod come into their facility, they shipped it right out. That's good customer service.
My three AA kits run great, not an issue with any of them. Would recommend them to anyone, very easy install. I just received an OPS 416 kit to try out in carbine length. When I get some time I'll work on installing it, and we'll see how that works out. Both systems have gotten high ratings from their owners. (.625 ultra light, .750 mid length, .750 rifle length, .750 carbine length) I guess my only AA complaint isn't he quality...it's the unavailability of a .936 kit...something the other manufacturers are starting to catch up with. PG |
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