I'm trying to restore a FH70 that has stood for several years. The breech has been lightly welded shut and even though I think all the welds have now been ground off, the breech is well and truely stuck in the closed position. Does anyone know if the breech has any locking mechanism that may be holding it shut? Also, is there any tricks to get the gun to raise and lower - the wheeled handle by the firing lever is jammed! Thanks.