Don Leverty

HI guys! I know that this discussion about chamber pressure originated with a question I had about hold open, so I'd to interject that issue again. Last night I removed the cannons from the 2 guns in question and inserted various different magazines. I was amazed by the variation in how high the hold open would rise with the different mags. In one gun, an FXO mag pushed the h.o up almost a half an inch, but a seemingly identical Schmeisser mag would only raise it by 1/16th or 1/32". (Sorry for the English measurments, Hakan). The spring strength seemed the same in both mags. The mag that worked best was a Mec Gar that I had worked on and added a stronger spring from Wolff's. I also switched out the h.o. devices between the two guns, and found the 1915 seems to work better than the 1916. Found what might be a minute burr on the surface of the 1916 frame -- the cavity in which the h.o. rests. (The notch of both breehblocks seems adequate, as do the magazine cathes.)


In other words, I still find an overwhelming number of variables to cope with. What do you guys think? Thanks.