Gary, Please excuse the sloppy art work (was still on my first cup of JOE when I threw this together)
. So as not to pull the hammer loose measurements were take with a stiff piece of wire probed down the bore and carefully marked,drawing is NOT to scale!,should be close enough for Government work?
Also noted the spring in full compression, is shorter than the depth of its pocket,something you'll want to keep in mind when you cut your spring so as not to have "coil bind" when the hammer falls.
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"Double guns are a sport and a pastime built into a beautiful package to which I attach myself when entering the great theater of autumn, those days now grow more precious because we are given so few".. Robin Lacy