Determining ideal loading maximizes ammunition effectiveness.
by Joe Carlos
Using a machine rest, I am able to find the bullet seating sweet spot for every gun I build. It takes me about a half day of range time if I have ammo already loaded and nearly a full day if I am forced to load while I proceed. If you don’t have a machine rest or are much more skilled at bench rest shooting than me (almost anybody is) just provide guidance for the owner to perform their own range testing.
Talking about “sweet spots” can become very esoteric with terms like nodes, null spots, barrel harmonics, etc. Even though I have a general understanding of this, these essays can be difficult to follow. Regardless, the goal remains to discover whatever it takes to get groups to be the tightest.
Group shrinking is often done by varying bullets, propellants and the amount charged, actually changing the harmonics of the firearm (such as Browning’s Ballistic Optimizing Shooting System), or changing bullet seating depth while observing group sizes to find the a “sweet spot.” We’re looking at the last one now. Combining techniques can help but various restrictions may prevent using them. I’ll also cover long seated ammo with 80 and 90 grain boat tail bullets used for single-fed slow fire events, though the techniques can be adapted for magazine-fed ammunition.
Read more in the June 2016 issue.