Micro Groove again

[KCSO]

I downloaded a copy of a post about using an Ideal #3 tool to reload in 1907 and that started me thinking. So I doug out my #3 tool and cast some bullets and loaded some 30-30's just to see how mine compared to those loaded in 1907. Now my tool marked 30-30 W casts a 140 grain bullet and cast from 1/2 and 1/2 ww and lino the bullet runs .309 from the mould , has 4 grease grooves and weighs 140 grains in a rnfp with a very small meplat. The nose of the bullet is well under bore size at .290 and there is no front band, the bullet crimps right over the top of the grease groove when using the #3 tool. After I got a batch loaded with 5.5 grains of Trail Boss in W/W cases I went to get a rifle and found that the only 30-30 I had handy was my old 1/2 magazine 336 with micro groove rifling. Normally I shoot a 311 cast bullet in this gun and shoot only a 170 grain gas check with a 300 nose. I went to the range expecting that i would not hit paper at 25 yards, which is my normal range for these squirrel loads. Low and behold the old Marlin put these bullets into 1" groups at 25 yards. By contrast the tailored loads run from 3/8 to 1/2" at the same range.
I don't think this bullet will hold up to either more velocity or will ever group any better than his but I am no tempted to beagle the mould and see if the same bullet at 311 will shoot any better. I sure don't see where some folks have so much problem with the micro groove barrels, as i have always been able to make them shoot with a properly fitted bullet. It sure is nice to do it all with tools that were made 100 years ago too.