422......why picky on ammo?

[pumpedTSI]

I have a 622 and a 422......both exactly the same pistol except for finish (alum on 622 and blue on 422) The 622 eats anything ammo wise including all the bulk ammo the 422 has feeding issues with the bulk Winchester Dynapoint and I cant figure why. I have dismantled both and compared under a magnifying glass the 422 to the 622 in regards to firing pin, spring length, bolt face, extractor hook, feed ramp, etc and they both look EXACTLY the same in all respects......NO differences other than the 422 recoil spring was approx "1/4 longer than the 622 spring. So why the feed issues with the 422? I changed mags from each and no difference, the 422 wont extract the cases always and causes a stovepipe or FTE.....maybe I can swap slides and see if it still occurs?
BTW, both are SPOTLESS clean....no gunk or carbon buildup...