Agreed on the KNS adjustable gas piston. I added and adjusted one for my AA Galil and it now throws reusuable brass like 6-10' instead of sometimes mangled brasss 30-40'.
Not sure of the need for the K&N gas piston? I don't recover my brass anymore. And while I have a Dillon 550 press and full reloading setup, and thousands of primers and bullets, I have not needed to reload in years. Let me explain.
From 1998 to 2010 the wife and I lived on and managed the local public shooting range just south of Boise, Idaho. Back then I had access to untold quantities of brass and ammo. I reloaded twice a week on the Dillon to feed my habit. I was a competitive long range shooter and practiced every day at least 50 rounds from unsupported prone position. I am a Palma shooter, and for those of you that don't know what that means, Palma is shot at 800, 900, & 1000 yards, with a .308 or .223 rifle of no more than 6.5kg weight, minimum trigger pull weight of 1.5 kg, iron sights, and a max bullet weight of 155gr for 308 and 80gr for 223. And yes, I shoot both 308 and 223 very successfully out to 1000 yards.
Anyway, the range was on 60 acres and I had my run of it during all hours, especially those hours it was closed to the public. Tons of varmints on 60 acres in southwest Idaho. To feed my varmint AR's I loaded thousands of rounds of 223. Needless to say I never shot it all so still have lots left over to this day... hence I don't worry about brass recovery. As long as it extracts and flies out I am happy. If it does so violently, well so much the better.
This Galil Clone is something to soothe long festering itch. I wanted one since way back in the 80's when they were imported from Israel but back then, and to this day, have long been out of my price range. I could probably (today) afford a Galil ACE but they are not the Galil ARM I have wanted for so long. The JRA Galil is likely as close as I will come to an ARM and with it I am happy.