[Milsurplus] 3 BC-611 questions

[Marty R's GI-stuff haunt]

 o chassis 'stretch'  Have a BC-611B that has had it's 
   top-connect eyelet pulll toward top preventing tight top-fit.  

   Any cure?

   Cud 'B model' be packing later, longer chassis??

 o was there a o-ring under the top case-screw?

 o Open sec'y on mic xfrmr.  Interchangeable with fone?  Mic xfrmr 
   marked 274 while fone xfrmr says 275.  Anyone have a spare mic?

   Will try to sparc-weld open w. 800v @ 2 uA.  Then comes a ceramic
   change-out as in BC-611A

Again, a noon Sat. mil-spec round-up this year?

Tnx!

  Marty