How important is the actual length of the case?

My 303 cases have not grown for some years and several of them are shorter than nominal. Should I discard the shorter ones or just trim them all to the shortest length? Would shortening them affect the accuracy at all?

These cases were all originally trimmed to 56.4mm. Some are now only 56.05mm long. They have been shrinking !

The case being that small amount shorter won't hurt...I would trim them all to the same length and that is so the crimp...IF you use one....will be even and neck tension will be easier to keep even....many/most chambers in factory guns are longer in the neck than printed "trim" lengths and your chamber is letting the case swell and that pulls the length back and makes the case slightly shorter...IF your pressure signs are OK then the cases are fine to keep using...just watch for splitting after several loadings and a strech ring at the case head end...hth.good luck and good shooting-loading!!

Thanks for that Bigdaddytacp. This rifle has a tight chamber and I only used to neck size. I have lost one or two cases to neck splits and none to head separation (well, not in 20 years anyway). I have no idea how many times these cases have been reloaded - maybe twenty, maybe only ten. I have now started reloading with no neck sizing. Instead, I use a paper hand towel patch to seat the bullet, followed by a dip of molten bullet lube/wax mixture to hold the bullet firm. (Initial tests show promising results - better groups than with neck sizing!)

PS. This technique is more work and much slower and requires some custom bits and pieces of loading stuff - which I make for myself. But it's fun for me.