View Full Version : M1A Sadlak Gas Piston Question

06-18-2010, 12:26 PM
I was looking that the Sadlak NM Gas Piston for my M1A and I noticed that they say that surplus ball ammo will not cycle. I have heard many things that do not work in am M1A such as soft points, but they seem to work just fine for me.

I have the Standard 22" Barreled M1A. FYI

Is there anyone with practical experience with this?

06-18-2010, 2:55 PM
Unless you're going to be shooting heavy handloads and your rifle is built up to NM specs, stick to the non-grooved version.

06-18-2010, 4:30 PM
That's just for the grooved piston. The non-grooved is fine for surplus.

06-18-2010, 5:40 PM
180 grains or above: must use vertical grooved NM piston, or else your gas system will be damaged over time due to higher than spec pressure.

150 grains or below: will not cycle with vertical grooved piston (not enough pressure to drive the piston due to gas leak through vertical groove), hence must use the normal piston.

US Surplus = 145-150 grain ammo, hence must use normal piston.