"Hook" on the wall of watch barrel

[Bill3]

I an replacing the mainspring in aBenrus pocket watch.  All went well until I wound the watch, then the hole in the end of the spring that is supposed to catch on the small hook on the wall of the barrel slipped.  It seems that the hook has worn a bit and will not hang onto the end of the spring.  The hook on the spring arbor works well.  Is there a way that I can augment that little projection on the wall of the barrel so that it will hang onto the spring?  

Thanks in advance!

[rodabod]

Mainspring barrels vary in design. Is the hook actually a punched-out section from the barrel wall?

[Bill3]

Instead of an actual hook this barrel has a tiny  V punches into the inside of the barrel.  The spring will initially catch on it, but a soon as pressure developed it slides over the progectin.

[Bill3]

That last word should be "projection".  Apologies for my poor spelling.