Did you eliminate most of the body taper, or, simply alter the shoulder angle? If you reduced the body taper, it's essentially a PPCx40*, which should be good.
In Y2K, I acquired a .220RUSSIANx30* shoulder reamer from PTG, and, based upon the reamer print and fired cases, had Neil Jones make one of his FL/Shoulder/Nk bushing dies. The goal was to have capacity equal to the .22 Waldog (222 &1/2 Rem.) - without the case forming. Except for case growth, the Jones die eliminates the, "dreaded click" (primary extraction).
My sole gripe is that, I did not order the reamer with reduced body taper ( I wanted to keep the capacity at a minimum without setting shoulder back) , thus, re-sizing results in constant case length growth and need to trim. I believe that Gene Beggs messed with the Neck : shoulder radius, and his last iterations greatly reduced the case growth issue.
Especially with a properly sized re-size reamer, your concept should prove quite useful. If you retained the body taper, I'd expect the case lengthening to slow, but not, "go away". Capacity wise, you''re right in the .22 Cal. wheelhouse, and your choice of twist should prove excellent with typical 51-53 Gr. BR quality bullets which are based upon the .705" long jacket. RG
