That makes for interesting reading, about using basic handtools for a precision project. Who knows? The rifle might shoot straighter with an angled muzzle. From my own experience, it is very tedious to get a straight cut with a hacksaw. I'm not saying it can't be done, I'm saying you have to be very attentive as to what's happening on every stroke. When I see my machinist friend turn out precisely cut and centered shafts, then bore out the center and put threads in the bore, I marvel at how mankind has progressed. He does this all the time, and I am awed.
I am equally awed when I get a good results with hammer, drill, saw, and file. More tired, but awed.