Gas-piston or Direct Gas Impingement on Semi-Autos

[Crash]

Do most centerfire semi-auto hunting rifles, e.g, Remington 7600, etc., have gas-piston or direct gas impingement operating systems?

Crash

[Uncle_Alvah]

I don't think they have either.
The gas impingment is like whats on the AR series, the gas piston is AK style.
Some of the early autoloader sporting guns like the Winchester 351 Self Loader were pure blowback(thats why they're so heavy).
Rifles like the 7400, Browning BAR(sporting, not the machine gun) series and such are recoil based.
I may well stand corrected........