Ron... I did a little research,
http://samuraiantiqueworld.proboards...=1&scrollTo=27
I'd say the pistol probably shot a 1 monme round. A 6 monme would be .62 caliber, and around 360 grains (a typical .45 acp is only 250 grains!). However, note in the chart that due to rounding to the nearest whole number (as the Japanese did), you could have up to the equivalence of a .38 caliber round still classified as a 1 monme, which would still work for that pistol. At .38 caliber and a grain weight of almost 150, this is almost a good .357 mag round size. Now you ARE talking about a bullet that could pack enough punch to do a good bit of damage. A glancing shot off a rib, major skin rippage, broken or cracked rib (survivable) and a good shock factor, both physical force and from a trauma shock standpoint.
And this is considering only a 1 monme size. The reference above says most pistols were 3-4 monme. So you can factually justify about any amount of damage you want with these bullet weights. (note that a 3 monme is equivalent to a .50 caliber round with a grain weight of right at 200..... strong stopping power)