You might find the Iannamicos' joint over at MachineGunBoards.com a big help--when my TSMG geekout was more active rather than "dormant and waiting to rise again" I learned a lot over there. PK, the master TSMG tuner and Merle Bitikofer, the "Drum Doctor" were both active when I was there...
Be warned, there is a bit of snobbery about West Hurley and Kahr-AO Thompsons, but at least in my time there they were generally a pretty helpful crew.
you might look into making something like a t-handle with a hook- nothing permanent, just hooks over the cocking handle and allows you to pull more from the rear-you remove it before firing- or put a sleeve over the cocking handle to give you more purchase - again, remove before firing
what haveu got- 1927, 21, 28 or m1a1?