Type 81SA's are hard to beat. The only reliability crutch ive observed is some and by some I mean like 1 in 8 proprietary mags sometimes fails to lock the bolt back on the last round. Its probably just the same faulty mag in the collection i have.
SKS is up there too. However on multiple occasions with different rifles ive observed them FTF with lead tip soft points.
My MR-1 was acceptably reliable. But nowhere near the extent of the above mentioned. My MR1 was ever so slightly picky with magazines and had FTF's with bullet gr higher then 62.
Buddy has a SU 16 Tactical. Surprisingly it has NEVER had a malfunction. But then again its only ever been fed brass cased 55gr FMJ...
I can also toss out there the MOST UNRELIABLE GUNS ive witnessed or owned...
Gen 1 TNW ASR in 9mm... occasional FTF, FREQUENT FTE ! even after a decent amount of tinkering, limited tech support, experimenting and over 1000rnd of factory ammo.
SVT 40... I dont care what the so called experts say. ive owned 3 of them over the years and have more tinkering and trigger time with them than most! They are finicky as heck to get running reasonably well. The most common failure I and many others experience is FTE. This is caused by either horribly corroded chambers, gas pistons cups and nozzles or a improperly tuned gas setting. But even then if you think uv corrected those issues other factors will sometimes come up that throws it all off again, weather and ammo. Light primer strikes is another lovely attribute to the SVT 40s lol its a highly novel and beautiful gun, but also over hyped with a heavy fanboi base lol
80% of Turkish made shotguns... With a few Western client collaborations like SXP's, PA-08s etc etc. and possibly some Turkish models like the Derya MK series and some Hatsuns as an exception... Most Turkish shotguns are in most aspects utter crap. Sticking to only the reliability side of things, most suffer from FTF and FTE enough so to drive a owner mad and then toss in the occasional light prime strike and the whole situation becomes borderline meme material.