Redhill: I used to be a "big" collector of Winchester 22 rimfire Rifles.
I had a bunch of them but decided to trade them off for money and or pre-64 Model 70's. I did pretty well trading them off but could NOT bring myself to trade away all my Model 72's, 75's and 69's. I kept 3 of the Model 72's including a "Target Model" 72 (with peep/receiver sights).
The 72's indeed had (have) long barrels IIRC they are 25" long and meaty - not quite heavy barrels but meaty.
I have shot more Model 69's than Model 72's but have done quite a bit with each.
I never had any feeding problems with my various Model 72's - but I do not recall shooting any shorts or longs in any of them just the long rifles.
I hope you can remember what happeend to that Model 72 of yours and you retrieve it - or you find another Model 72 to replace it.
They are nifty and good shooting little Rifles.
Hold into the wind
VarmintGuy