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“The soundless death coming from the ‘nowhere’ always shattered the guerrilla morale. The initial shock and the ensuing panic usually prevented the enemy from executing necessary defensive measures. By the time their leaders decided what to do, it was too late for them to do anything but flee or perish. So whenever given a chance we killed in silence.”

I can trace my interest in shooting suppressed all the way back to those 4 sentences. It’s a quote from a WWII SS officer in Devil’s Guard, a book about the First Indochina War. I first came across the quote as a reference in another book, Silencers In the 1980’s —which I read when I was young and impressionable—it has stuck with me the 30+ years since then.  

If you are shooting suppressed and reloading your own ammo, its helpful to understand if your subsonic projectile is flying with any stability - if it is not flying with stability you'll find problems with accuracy and you may even get bullets that tumble in flight.  

The formula I have adopted for calculating subsonic bullet stability is included below, written in Microsoft Excel format:  

Stability Factor =((WT*(20.62*(DIA^2.25))^2)/ ((TWIST*(BL^2.25))^2))/1-(V/5705))

We've translated this formula to HTML code and included the calculator above for my own (and your own) ease of use.

-JSharps