WK 180 piston issue.

SA85M1 said:
Thinking the way the system is supposed to work,the set screws go in from the squared end...with the second one behind the first to hold it in place..
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Great, thanks for the info, I found it strange that you had to screw the set screws in so far and leave such an opening on the square end, I thought too much gas would escape and not cycle the action. I’ll be trying it out this weekend, hopefully it works out. Thanks again!
 
Ustauk said:
Ontario Plinking and Outdoors has some info on the TNA gas block, including to not overtighten it, as it can break,https://youtu.be/o2QR0EhxSnI .
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I’m glad I watched this video before I installed mine, I was a lot more careful than I normally would be when screwing something together. On another note I heard from TNA and spoke with Dave who confirmed the set screws go in the square end, cover the gas hole and then back it off to about half and secure with the second screw. Really appreciated the call back! Unfortunately any rumours of a stronger or different piston is just a rumour.
 
Crap,I was interested in a piston swap as well...I'm not 100% certain as to what causes the piston failure/breakages,.but it's small and I suspect the metal in them kinda sucks...maybe...
 
Most of the breakages are due to the gas block loosening and moving, and the gas piston going out of alignment. That forces the piston to flex as it cycles the bolt. The pistons always seem to break at the sharp shoulder where it necks down, which I'm guessing is a poor design that creates a weak point in the piston. These rifles are also over-gassed, which puts more stress on everything than is necessary.
That's why keeping the gas block tight, TNA's brass bushing and TNA's adjustable gas system are recommended by alot of people. Those three things go a long way to keeping these rifles reliable.
 
Got out to shoot this rifle,and put 100 rounds through with no problems,but a few issues did show up..the adjustable gas valve from TNA backed itself out a few turns,and both set screws inside it moved out of place.,put them back in and used a dab of blue loctite...The gas block itself was fine,but I removed the set screws beforehand and dimpled the bbl with a titanium drill bit and put both back in with red loctite...I also picked up some low temp grease and gave the inside of the upper and the bolt carrier a coating.
CLP on the bolt itself...
For a gen 1 I got better then expected accuracy with 55gr Hornady fmj reloads...she loves them...no problem making one hole at 50m with 5 round groups once I zeroed the scope...
 
100%, accurate rifle - it's that long heavy barrel. basically loctite everything then ... tighten it, grease it, shoot it. if it stops running then ... curse it, tighten it, grease it, shoot it. carry on.
 
Not positive grease is the right thing inside the receiver. Grease will hold dirt in place and get hard with temperature and time. I suspect CLP or the like in the receiver and BCG would be a better choice. ARs seemed to run fine with a thin lubricant.
 
Seeing some reports of wear on the inside of the reciever,made me decide to try a light coat of grease..I used a low temperature (to -45°).type,available at any CT store...considering the shooting I'll be doing,it shouldn't be a problem...
 
tenringbound said:
Got my adjustable gas valve, little confused with where to put the set screws. I put the set screws in from the square muzzle facing end until half the gas hole was visible and then tightened it with the second screw as per TNAs instructions online. Is this the right way to put these in or do they go from the threaded side that faces the piston? Checked on YouTube, Reddit, here, but I haven’t found any that say which side the screws go in. Any help is appreciated!
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Put the first set screw in from the muzzle end until it covers the gas hole completely. Screw the second screw against it (again from the muzzle end) to lock it in place.

If you need to adjust, remove the second screw then back the first out to slowly uncover the gas hole, putting second screw back in to lock the first again....

Mine needed 0 adjustment. Rifle cycled just fine and spent cases were ejected at about 4 o'clock in a circle about 2 feet across.

I didn't use loctite.
 
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I Dont Care About You said:
Not positive grease is the right thing inside the receiver. Grease will hold dirt in place and get hard with temperature and time. I suspect CLP or the like in the receiver and BCG would be a better choice. ARs seemed to run fine with a thin lubricant.
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Have to agree with this. Maybe a very fine layer of grease on some key points but I would keep it to a minimum as it does collect dirt (whereby it effectively becomes a cutting paste / lapping compound).

Something finer like a CLP would be my choice.
 
Paul_T said:
Put the first set screw in from the muzzle end until it covers the gas hole completely. Screw the second screw against it (again from the muzzle end) to lock it in place.

If you need to adjust, remove the second screw then back the first out to slowly uncover the gas hole, putting second screw back in to lock the first again....

Mine needed 0 adjustment. Rifle cycled just fine and spent cases were ejected at about 4 o'clock in a circle about 2 feet across.

I didn't use loctite.
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Thanks for the reply, much appreciated! Surprised that the hole is completely covered and still runs the action. That’s how I plan to run mine, one round at a time and adjust as needed. Sounds like the ideal setting is the 4 o’clock ejection in a 2 foot circle. Reminds me of when I had an over gassed CSA VZ58 in 5.56 which was shattering bolts and bolt parts on people. Sent it off for warranty work where the replace the piston with a smaller diameter one and the gun ran perfectly after that, threw empties about 6 feet away instead of about 20 feet lol.
 
Hmmm..I set the first hex screw in covering 50% of the hole on the first trip...ran fine,even with the entire assembly working itself loose...I'll adjust it,and see what happens..
 
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