So I tried the tilt test just now. The op rod and bolt are moving just fine but the piston is slow. Like 4 Mississippi to drop slow. Its clean and dry and moves freely with the gas plug out but with it in it drops quickly as the hole in the piston clears the gas tube to the barrel then slows until it clears the hole in the bottom of the gas block.
Failed the tilt test
- Thread starter RSK
- Start date
Sounds darn near perfect to me 
The "Tilt Test" applies to your OPROD
The "piston drop test" is a different thing.
Put a empty mag in
Lock back the oprod
Point muzzle up
Push piston in with your finger
Remove finger quickly
If it drops like a stone... You may find that your rifle is having issues cycling 100%..... Or you will have these issues very soon.
If it drops with some apparent vacuum , this is a good thing.
Explanation??
Vacuum means good gas pressure behind and subsequently inside of the gas piston
Lack of vacuum means piston is not able to take full advantage of gasses and actually allows gas blowby at the piston... Which will eventually cause cycling issues.
There ya go
Yer rifle has not failed
The "Tilt Test" applies to your OPROD
The "piston drop test" is a different thing.
Put a empty mag in
Lock back the oprod
Point muzzle up
Push piston in with your finger
Remove finger quickly
If it drops like a stone... You may find that your rifle is having issues cycling 100%..... Or you will have these issues very soon.
If it drops with some apparent vacuum , this is a good thing.
Explanation??
Vacuum means good gas pressure behind and subsequently inside of the gas piston
Lack of vacuum means piston is not able to take full advantage of gasses and actually allows gas blowby at the piston... Which will eventually cause cycling issues.
There ya go
Yer rifle has not failed
Last edited:
ipscgraz
CGN Ultra frequent flyer
Free falling as you mention indicates that the piston and gas cyl are good. Don't forget that the piston sliding down will create a "vaccum" and the air has to come in behind it through the the small hole in the barrel. Take a drill bit and confirm alignment of the hole in the gas assy and the hole in the barrel, and maybe use an appropriate size drill bit to clean any carbon out of the gas path.
