|
Performance update time...
Within the last month my m4 has thrown 2 pistons (the last lasting less than 500 rounds)
"hmm" i think to myself, that can't be right...
Received a new area 1000 piston (the previous two were the stock piston and a guarder blue) and since i already had the mechbox open I also installed a guarder sp100 just to get off the PDI wagon.
Before installation i completely stripped and degreased the upper mechbox - and i noticed something i hadn't before when the rail guides had grease in them - bumps and a few small voids. A few raised nodules on the centre rail guides - perhaps the cause of my problems?
I regreased and installed the components first without doing anything about the rail guide problem, and everything worked alright, good but not great ROF on auto.
Then I proceeded to disassemble and degreased again, this time though I sanded the rail guides and the casing where the piston travels with 250 thru 1600 grit sandpaper. This left a mirror finish on the inside and completely smoothed out the areas I was concerned about.
After regreasing and reassembly another testfire revealed a HUGE increase in ROF and a decrease in the amount of noise coming from the motor.. So it looks like problem solved!
So just a heads up everyone, next time you crack your upper perhaps degrease and take a good hard look at the bare metal.
|